Raccoon creek WMA POTA with the sBitx V3 SDR transceiver

Today saw me head over to Alabama to activate a nearby park that I have never been to before. Us-9875 Raccoon Creek Wildlife Management Area is a beautiful place right on the Tennessee river between Stevenson Alabama and Flat Rock Alabama.

I drive over to the WMA and find no one there at all, this is awesome as I like it when I have the place to myself. It gives me the freedom to setup the radio anywhere or in any manner I choose without having to worry about people walking into the radials or anything like that. Well, I get there and promptly decide to setup on 20 meters as I wanted to not spend a lot of time today activating as I wanted to also record a YouTube video for our brand new channel about amateur radio as well as have time to enter and upload the log from today and edit the video once I got back home.

If you want to see the video I made when I did this activation, the link is here. I didn’t film the whole activation, but rather pulled segments in and just did some of it, so you might be in it and you might not…lol. If people want the whole activation recorded in all it’s lengthy glory, I am not opposed to doing that, but I will need to hear that from the people…

When I want to do FT8 in the field I always grab this radio. The sBitx V3 is an SDR that is built around a Raspberry Pi SBC and uses a touchscreen for most functions. It only has two input devices on the radio, the VFO knob which never changes and the multi-function knob which literally can be used to adjust everything else…literally. It does have ports for a CW key, headphones, and a microphone on the side right above the power switch too. Since it uses a RPi4, it can be driven with a mouse and keyboard and during this activation I use the mouse to select FT8 stations to call. It is really handy for that. I find that if I am simply entering a call sign to chase on FT* I can use the built in keyboard instead of taking a separate keyboard. Another thing it has is Bluetooth, so Bluetooth devices will work on it too…such as a keyboard… I really like this radio if you have not figured that out yet.

Propagation was all over the place today as you can see on the beacon report above that I was weak at -19dB into “3” land but just a half hour earlier I was able to work JI3MJK in Japan! That is almost 7000 miles away!!! So if your activating and it seems like no one can hear you and you are about to give up, I would recommend that you give it another half hour, if possible, as the system might flip in your favor! That is what happened today.

I grabbed this photo below of the screen during boot up, it shows the OS version which is JJ’s 64 bit version 3.025 and that it knows who I am and where I have set the GRID to. This is important if you are doing POTA as you need to communicate that when you work FT8 at some distant location. The FT8 community is really into grids and want to collect them all…so pay attention to your grid. It is also showing the FT8 stations as they come in as well below that in green letters. Fortunately, it is really easy to change the grid on the sBitx so you dont have to worry too much about it.

So I setup in the truck and to be honest about it, I am really starting to like this concept. I am in the shade for the most part, if I am running FT8 only, I can run the engine and have AIR CONDITIONING at my POTA operation!!! Can we say WINNING!!! Ha Ha… I have done that once so far when I was in Florida if memory serves me but I would have to check. Using CW is a little tougher though. The diesel engine is loud enough to make copy of weak stations really hard so I don’t run it if I am working CW.

I normally try to work some CW though as I really love the mode so I normally will roll down all the windows in the summer and put my windshield sun protector in the window and work a bunch of those CW ops if the bands permit it.

A neat little addendum to the sBitx radio is that since it is driven by a Raspberry Pi 4, it can use a mouse and keyboard if you prefer it. Supposedly it has keyboard CW character generation too, but I have not attempted to do that yet. So if you are not able to send very well, this might be a solution for you. The mouse makes it much easier to choose stations that are calling CQ so you can pick them out on your end and you are not obligated to just call and answer CQ calls yourself. Farhan put a lot of thought into this radio and it shows.

Here is a little discussed subject…extra gear. I know we all take it with us but what do you normally carry with you when you go into the field? I have done POTA long enough now that I have sorted it out to just what I need and some redundant spares of failure prone items. Things like extra coax and another antenna are always in the spare tote.

The location that I setup at did have a really nice view of the river. This location is right next to the John Snodgrass bridge. This is the bridge over the river for Alabama Highway 117 to Stevenson.

As you can see from the logbook, there was a great run on 20 meters CW then another great run on FT8 as well! I even netted a J call on FT8! What a great day to do radio and the weather was great to boot.

Dual POTA activations US-0716

This park is the second nearest park to me past US-2169. Since it is a further drive, I tend to not activate it as much. This weekend I was able to actually activate it in both states in two consecutive days.

As you can see above, the band was really active on CW as well as FT8 on this day at Eagle’s Nest and I made quite a few contacts in the mid afternoon here. When I setup here, I am right on the edge of the road so I have a lot of road noise to contend with here. I ended up going to earphones when I operated CW just so I could hear when cars would go by. That was OK though as I could hear plenty well enough to get a bunch of QSOs in the log before switching over to FT8 for a while.

Yours truly next to the sign for this location and the below picture shows where the truck is located in comparison to the road as viewed from the sign. There is an upper parking area too but the spot where I parked today is fully inside the park so I simply setup here if I don’t have a lot of time.

I quickly ran the radials out into the weeds and checked the antenna system on the nanoVNA and it was close enough to use (I think it was 1.5:1 SWR or something near that). I really thought I would simply get 12 QSOs in the log and move on today as the bands have not really been the best lately, but that was not what happened at all!

Getting on FT8 after a strong run on the CW portion of the band was fun as well! I am really starting to enjoy this whole concept of multiple modes in a single activation.

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The next day saw me wanting to activate the Georgia side of the park as I again had some free time in the afternoon. Well, let’s do it then. I strike out to the battlefield and when I get there, my usual spot is completely clear! I am stoked! I back into the tiny parking lot (it only has two spaces for some reason) and get the radio setup in short order. Well, this is where the problems start. I power up the radio and there is this broadband noise that is wiping out the band now! I investigate it for a minute and realize they have one of those huge temporary LED road signs setup across the road. This has to be the problem because there is literally nothing in any direction for over a mile easily. Well drat. I decide to expediently break down the radio to the point that the radials are rolled up and laid in the truck bed and the antenna is just stuck in the bed with the radials and I left the antenna mount on the truck hitch.

This is the culprit as best as I can tell. It is the only thing that was in the area for probably a mile in any direction that was not there the last time I activated this spot. Have any of you ever had this sort of problem with these signs?

So I move down the road about a mile or so and then take a side road out to a pull off next to a field with a bunch of monuments in it and as a bonus, it was also in the shade! These bicycles were about the loudest thing to go by while I was there too. A couple of cars did go by, but they go MUCH slower on this little one lane road since it also has the bicyclers to watch out for.

Getting to operate in the shade is kind of a special thing for me as I dont usually have a setup that allows for that.

And this is what the band scope looked like with me in a new location. Nice and quiet. There was a disturbance in the bands today though as I had a K index of 3 and it was not near as easy to get enough contacts today as it was the day before on the ham radio… In the photo I am working AF4DN on FT8 on the sBitx V3 and it was about to dry up for FT8 contacts.

Once I finished the FT8 portion of the activation, I wanted to use the Ten Tec Argonaut V radio so I switched them out and got it on the air. In the photo you can see that I was on 14.050 mhz, but the logbook shows 14.051 mhz. This because I was calling CQ and after a couple of minutes I heard someone tune up on my frequency and then they started calling CQ… Rather than get upset, I simply spun the dial a little, called QRL (Is the Frequency in use?), and then started calling CQ again. It took a while but I finally worked a half a dozen contacts on CW and at that point I had cleared all the callers I could hear and decided to go QRT and get something to eat.

This is one thing about the Argonaut V that I really like. This radio has a good ole S meter! I love to have a real meter movement if it is feasible to do so. Several of my radios do not have this features and I miss it. My old Ten Tec Omni 6+ and my Ten Tec Omni 7 both have S meters, although the Omni 7 has a digital bar-graph style on the digital display and not a physical meter, it is still there and does give you some sort of indication of the signal strength.

The operating position is starting to get very comfortable to be quite honest about it. I am starting to like operating from the truck more and more. The first year I worked many of my activations from a picnic table in the park and I had to carry all my stuff across the park to the table and back every time. This was not too bad, but it sure is convenient when you can simply setup in the truck cab in just minutes and I can even operate in the rain in this position without much problem, so rainy day activations are a thing for me now.

Two things of note about these last two photos that are of interest to me and maybe you too. The first one is that I have worked W7RF (#14 in the logbook) and this might not mean anything to you, but he is the inventor of the keyer I was using in this activation! He owns Hamgadgets.com and I love his Picokeyer CW memory keyers! I thought I recognized his call and when I ran it through QRZ, I knew I have to email him and send him a photo. he wrote me back and we had a great little exchange over it, turns out he is an avid POTA hunter as well as many other things. I count it as special to have him in my log. The bottom photo shows the parking lot I was at when I started this blog post today. It is also where I apparently left my storage case for my radials with half of the radials and ground weights still in it! I went to breakdown the system at the other location and could not find the storage case. So I packed it up and drove back over to the original spot and there it was, still sitting in the grass right where I left it… What a day.

Testing the DROK 5 volt regulator for the sbitx V2/V3 Amateur Transceiver

Tests were done today and the results are in… the DROK adjustable voltage regulator is a clear winner in my sBitx V3 radio. This is a simple multi-choice voltage regulator circuit that can be used on a whole host of applications. That row of SMD resistors across the top is for fixed voltage applications and then there is a small potentiometer in the upper corner for the variable voltage applications. I just dialed the potentiometer down to 5VDC and called it good… Let’s take a look at what I found today when I compared the results of the old voltage regulator to the new DROK regulator on the oscilloscope.

When you buy these little power supply circuits, they come attached to each other and you simple pop one off to get it out to use it. So I broke one off the set and soldered a set of header pins into it and then connected it to my homebrew variable bench power supply, then also to my HP 8840A/AF bench multi-meter and my Siglent Technologies SDS1202X Oscilloscope. This allowed me to vary the voltage applied to the input and to measure the output voltage as well as see what the quality of the output voltage looked like. Now, to be fair, I didn’t load either the original unit or the new one, this is simply static voltage output being viewed for cleanliness.

The below photo shows how it looks on the workbench when you have a power supply, a scope and a multi-meter all connected at once to a tiny little circuit board…haha.

I first connected the old one to see what it looked like on the scope and to be honest, it didnt look too bad at 13.8VDC. It has some noise on it, but it was not too bad. But then I thought, “You know, my truck power port is more like 12.4VDC so lets lower the input voltage and see what the waveform and output voltages look like. This is where things got real interesting. I found that the noise was akin to a sort of high frequency ringing and the scope could not get a clean trigger on it. So instead I turned on the persistence mode and then set it to a 1 second decay rate so it would build up on the screen and this gave me the visual that I could share that is relatable.

All of the input (13.8 to 12VDC) voltage adjustments that I did only changed the output a few milli-volts, it was so little change that I didn’t even bother recording it. I adjusted the output till I was at 5.0872 volts, this is only a 1.7% variation from 5 volts so I figured I would be good to go here. The original was off by more and it worked too, so there is also that.

The first photo of the oscilloscope screen is from the new DROK voltage regulator showing the output from the new board. The variation is less than 80mV as you can see the cursors are not right down on the waveform, so I figured it was close enough for what I was doing. Might have been 75mV if I had gotten really close… Adding the persistence to the waveform allowed it to fill the screen and gave me a bar I could more easily measure.

Below is the original voltage regulator with the supply voltage at 13.8VDC. I was intrigued by the fact that a higher supply voltage made the device work better. So my Astron RS-35M power supply was making it work better in the shack where I was trying to recreate the problem from when it was in the truck…lol. You can see how the wave form has grown with all the signals below the main area of concentrated garbage. With a 1 second decay rate the old wave forms would fade out after 1 second so it would not simply fill the screen with a yellow bar. I really like these new oscilloscope features. These are all in the megahertz frequency range too…

Below is what the old regulator looked like with the voltage reduced to 12VDC. Look at all that RF hash! What a terrible DC waveform… It has completely filled in the 1 second decay rate with trash. This measures about 137mV so if you do the simple math of 75mV and 137Mv you come up with about 50% reduction in RF hash on the 5VDC bus. That is a solid 3dB of noise that I removed or in ham speak a full S unit…(At least that is how I understand it). That is a pretty significant amount in my book and I for one am glad the email group found these devices and shared it with the rest of us.

I call this a win. If you have an sBitx V2 or V3, this is a worthy upgrade and it really is quite simple to install. You have to solder in some header pins (you can recover the ones in the old voltage regulator if you don’t have new ones like I had today) and simply plug it into the header on the main board and your done. Remove a few screws, unplug a few connectors, solder in four pins, unplug the old and plug in the new, reconnect the plugs (they are all different so you can’t put them back wrong) and put back the 6 or so screws and your done. Literally 20 minutes start to finish. I wished I had done it sooner knowing what I know now, I have had my DROK boards for a couple of weeks at this point…so sad… You can get them from Amazon for real reasonable money too. here is the link to Amazon if you want to get some for yourself.

Link to DROK mini regulators

POTA on the 4th of July…hold for second operator.

Today I went for a morning POTA activation at US-2169 and on my way over to the park, I gave KG4WBI (Roger) a call and invited him to join me. He agreed and after a little while of my working some CW on 15 meters, he arrived with a thermos of coffee and an eagerness to make some contacts!

Since I was ahead of him, I went ahead and setup the station complete with a full compliment of radials so I could use any band I wanted (of the 5 I have hamsticks for at this time...) and got it tuned up on 15 meters by making a slight adjustment to one of the radials. As you can see, I chose the usual spot for today’s activation. This was on purpose as I knew the lower area (which is actually where I kind of wanted to go, to be honest) was really busy with holiday traffic. This also meant that there would be more RF noise down there from inverters in the campground and such too.

This upper parking lot doesn’t see near as much traffic so I knew that it would be a much quieter RF environment. Sometimes you just have to choose between comfort (the lower area is in the shade under a bunch of old growth trees) and a quieter location so I could hear better. I chose to hear better since I knew Roger was coming. It wasn’t too bad, but it did get fairly hot towards the end of the activation to be honest about it.

With the antenna strung up and adjusted, I need to choose a radio. The radio turned out to be the Ten Tec Scout 555 because of the power output on SSB(50 watts). I knew we would be using SSB today and wanted to be able to make a bunch of contacts with it since Roger was going to be there as I am secretly addicting him to POTA a little at a time…hehehe. It worked as we operated together while he was there and I made sure he got enough contacts to get his first activation from US-2169. Now to get him an account and to upload his first log so all the hunters will get credit for his contacts too.

The Scout is a really great POTA rig as it has minimal controls on the front to the point that it has what you need and nothing else to be honest about it. It needs a couple more in my opinion and I may just get another one to build into something fun with some more front panel controls on it. But for now, this one works perfectly and I don’t want to risk killing it as I use it as my SSB POTA machine now. Before this one I had only made a handful of SSB contacts at parks and now I have dozens in the time since purchasing this radio. I really love the compact nature of the radio to be honest, I compare it to my Argonaut 5 in usability with more RF output…

Here is another insider tip…You can connect the CW key and the microphone at the same time, this doesn’t seem unusual till you find out there is no mode switch to go between these two modes. You simply start keying CW on the key and it will transmit CW, and then you can key the microphone and transmit SSB in the next moment with no other interaction with the radio other than picking up the microphone. This is really awesome, but it comes with a caveat. The radio is transmitting CW on the SSB mode. This means that you have to adjust the frequency off from the desired frequency by the amount of the side tone, which is about 700 hertz. On top of that, you also have to shift the radio opposite of the sideband direction you are using. So if your on 40 meters, then you have to be 700hz above the desired frequency and if your on 15 meters, then you have to be 700hz below the frequency. This took me a little bit to figure out too as I am used to being able to simply dial the frequency and call it good. So in the photo below, I am actually on 21.042mhz… As the radio warmed up, it shifted in frequency a little. This is why it is important to do two things, let the radio warm up before getting on the air and look at the display from time to time to confirm things have not changed.

What is nice about taking a pile of pelican style cases (none of them are actually pelican cases) is that you can have a ton of extra gear with you so if something goes awry, you have spares. Another thing that happens is you will have access to your favorite hardware like my N3ZN cw key! So I get it out of the case for the Argonaut 5, which is where I store it normally and use it for this activation. The Scout has two key inputs on the back, one if for a straight key and the other is for a paddle. Well, if I use my Picokeyer, then it goes into the straight key input. The paddle input is fed to a Curtis keyer chip and that is built into the radio. The only downside to this keyer, which works beautifully BTW, is that it does’t have memories. I like having memories for POTA as you end up sending some information A LOT and it takes some of the sending burden off of me so I can log and check the radio and such. Turning the page on the log book seems to be a good reason to use memories on the keyer too… lol. If you have the need for a dead simple CW memory keyer, I can recommend the Hamgadgets Picokeyer VERY HIGHLY, it works flawlessly and runs what seems like forever on a single coin cell battery. I am closing in on a year for this one and it is showing no signs of needing a battery yet…

No matter how many radios you take though, if you forget your log book, you will end up logging in your journal…like I did today. I luckily took my journal with me as I like to make notes about all sorts of stuff while I am out and this is another good reason to have it. This is not the first time I have defaulted to this notebook either, it has bailed me out more than once…lol. I did have plenty of pens though so that wasn’t a problem.

Since I got there before Roger, I built the radio out and hopped on 15 meters CW and started calling CW POTA and got some really interesting answers to that call! I worked a station in the UK as well as Germany! The Hamstick is not the worst antenna out there is what I have some to understand. If conditions are not too bad, I can easily work Europe and South America on 15 meters above. Today was no different. I was able to get a couple of DX stations as well as K2E special event station!

Once Roger arrived we switched over to SSB and attempted to make some contacts first on 15 meters, and then 17 meters with literally zero answers on SSB. You see, Roger is still working on his code so he prefers SSB at this time for things like this. So rather than frustrate him with having to listen to code he is struggling with, I opted to set the hook deep and get on SSB.

I think my idea worked, he was really stoked to work so many ops in such a short time. We had a blast and everyone was super nice while we bumbled around handing the mic back and fourth. It was hilarious at times, but we had fun so I am happy. It happened so fast that I had to come up with some really fast shorthand to know which calls we had given “Two Op status” to and which ones I worked by myself. Plus the notebook was also the wrong one and the calls were happening so much faster on SSB, the notebook is a mess.

I can honestly say that taking a second op along to do multi-op POTA is really fun and if you have not done it yet, consider giving it a shot sometime.

The below photo shows you what it looks like to make sure you are hydrated on these hot summer days in Georgia. I have a Nalgene bottle which I am using first since it is not insulated and then a Hydra-flask which is insulated and makes for cool water even when it is burning hot outside of the bottle. On top of that we were drinking coffee while there too, that is just silly if you think about it…

This is the messiest logbook I think I have ever created. Notes just scribbled here and there, edits run roughshod through out the 5 pages, and you can see that it means we had a great 4th of July activation. Thank you to all the hunters that came out to support us on the air and I look forward to recreating something like this again in the near future.

73

David - WK4DS

Dual radio POTA activation? Sure!

Today I setup both the Ten Tec Argonaut V as well as the sBitx V3. This was because i was not sure if the sBitx V3 would hold up the entire time. You see, it has had an ailing 5 volt regulator for a while and I was planning on replacing it later today, but first… POTA!

So I go to US-2169 and setup in my usual spot and get out both radios so that I can work CW on the Ten Tec if the sBitx flakes out on me. It didn’t, but since I had already gotten it out, I used the Ten Tec Argonaut V anyway and worked what CW I could with it. You see, today was another day that I stayed above 20 meters the entire time. That was the plan from the outset and it was quite successful too. I love using 15 meters in particular since it goes over seas easily for me. I will usually work several DX stations if the band is open and today is no exception. I worked 5 DX stations over an 18 minute span of time, not bad for a 15 watt radio… I worked so much FT8 is short order that I almost didn’t need to setup the CW station at all, but I wanted to work some CW anyway so I just got on the air with it and this is how it went.

The operating position was a little crowded today but not too bad, I used the hard case for the Ten Tec Argonaut V as a table of sorts to sit the radios on so I was able to move them back and out of the way of my writing surface. This left plenty of room for the nanoVNA and my other small items I use when activating a park. I have gotten really comfortable with setting up like this, I can set this up in just minutes and it requires zero use of the park infrastructure (such as trees or picnic tables) over the parking space I would consume either way and some space for my radials.

So in a previous blog post I had mentioned that I was going to use the smith chart on the next outing to show how you get way more information about the antenna under test with it instead of the simple SWR graph and here it is. Contained below is the 15 meter plot from 20.5mhz to 21.5mhz and the marker is resting at the upper limit in the photo. The center line across the chart is purely resistive measurements, anything above this line is inductive and anything below this line is capacitive in nature. As you can see on the display, the line representing the span I am looking at, 20.5 to 21.5mhz, is all above the line showing that my antenna system is inductive in nature so it will have some inductive reactance to the signal. The very center of the chart where the smaller circle intersects the line is 50 ohms - resistive (right below the flag from my measurement). As you can seem the further you move away from this point, the further from 50 ohms you get.if it were to be something like 100 ohms, you would need a 4:1 transformer to correct the impedance mismatch, this is why antennas need transformers. The characteristic impedance of the antenna is not usually 50 ohms which is what the transmitter is designed to see.

In the second photo I have switched the chart over to a simple SWR plot versus frequency and you can see how it is easier to read for the lay-person. It does give you the data you need in the firld really quickly and make it easy to know if your antenna is short or long and if your radials are good to go and such. This is what i use most of the time in the field to just make sure the antenna is presenting a good load to the transmitter.

In the above photo I learned something strange about the sBitx today. The two clocks don’t have to be synchronized to work. FT8 is not time forgiving, your radio time marker has to be fairly accurate (within so many milliseconds or maybe a second or two max) or it wont make connection at all with the other stations. As you can see in the lower photo, FT8 worked perfectly and I made several contacts with this mode so the computer clock must not matter at all… I don’t know what is going on here but it works so I dont question it.

Today saw a bunch of DX early on which always makes my day. But all in all it was a great day for POTA and I was stoked to get 21 calls in the log. Until next time, dust off that key or microphone and see if you can get a park or two into the log.

David

Scout…ing for contacts POTA style

Today saw me field a “new-to-me” radio, a Ten Tec Scout 555.

If you have never seen one of these radios, you are not alone. This is a radio that was produced for only about 15 years, towards the end of the company’s life before it changed hands around 10 years ago. It is unique in that it doesn’t contain every band but rather only one at a time. These little modules each contain the special bits to make it work on each band they are designed for and the goal back in the day way to just get the bands that you use. Turned out that these radios quickly formed a cult following and they all wanted the “whole set” of bands for them. I have the whole set of bands thanks to KG4WBI rounding up an 80 meter module and presenting it to me as an early birthday present. Once I had the whole set, I felt this iconic antique needed a better way to travel around when in my truck so I went to Harbor Freight and grabbed an Apache 4800 hard shell case for it. The Ten Tec Scout fits perfectly alongside the set of band modules. I even created a pocket under the radio to store the power cord so I have the whole rig in the case. (The 20 meter module is currently installed in the radio in the below photo)

Today saw me back in the “truck-shack” (I think this is what I am going to start calling this in the future) and setting the radio up on the hard shell case in the passenger seat. Today’s setup was not for power access though as my internal power cord it only fused to 10 amps and the Scout draws that much on transmit normally since it is not user adjustable on the front panel…yet.

I have found a website about the Scout that is a literal treasure trove of information about this radio, mainly in the CW mode, but a wealth of information none the less. I found the website by watching Coastal Waves and Wires video here. The website is by NA5N and is linked here for quick access… His mods for the Scout are pretty extensive an he does a great job of documenting the mods as well as explaining the process the radio uses to transmit and receive and he even has these hand drawn graphics that are amazing.

Back to the activation after chasing a rabbit for a minute…

So today I started on 40 meters as I figured I could make a good many contacts there on SSB, problem is that I have tuned my ham sticks for the CW portion of the band and the 40 meter ham stick is not very broad banded so it really wasn’t going to allow this. What did I do then? Well, I got on CW and made a few contacts before moving up to 20 meters where the antenna is broad banded enough to cover the entire amateur band space.

A couple of noteworthy items here. The 36Ah battery weighs almost nothing but packs a ton of energy. I use it from time to time to power my POTA ops but most of the time it is backup power in my shack for use during power outages and emergency nets and such.

The key I am using today is the Gemini and is a great little collapsible travel key. I had one little problem with it right after buying it due to the center post working loose but other than that it has been flawless. Great portable CW key if your wondering.

The antenna setup is as follows, hamstick riser, hamstick in QD socket, then several radials to form a counterpoise. I have taken to running one or two LONG radial now to play with how they interact with the hamstick antennas and so far it has been interesting to say the least.I found that on 40 meters, if the long radials were pulled taught, (I “anchor” them with a simple weight so I dont need tent stakes) that the resonant point would be well under 7.000mhz, but if I pulled just enough slack in them that they laid on the ground all the way except the first 8 feet from the antenna. Imagine gently curving down to the ground about 7’ from the yellow antenna riser then laying on the grass the rest of the way out. This moved the resonant center value up into the CW portion of the 40 meter band.

The point here is that the length and position of your radial field is absoloutly critical to your antenna system as a whole. The more I play with these radials, the more I learn about how they interact with the system and how important it is to measure your antenna prior to starting your activation if you build it on site.

In the photo below you can see how the radials were setup for the 20 meter band.

Remember at the beginning of this story where I mentioned “ominous” clouds? Well, here is a photo of them to show you what I meant. That looks like rain to me, I did get by without getting rained on before finishing, but that looks EXACTLY like the kind of clouds that bring rain to my area of operation.

Some thoughts on the logbook from today. I have gotten very comfortable with paper logging in the field and then transcribing at home. I did it today actually and it was fine…for the most part. But there was a couple of times when I needed a helper to log for me when I was working SSB. SSB happens so much faster than CW does for me that I was struggling to keep up with the log.

If you will notice in my other posts, I will number the QSOs and even write out the time on the FT8 QSOs as they are pretty slow to complete for me. But once I moved to 20 meters today and jumped on the air with more than 17 watts, things got sporty! I literally stopped writing line numbers, abbreviated most of the time stamps and even left out some of the states just to keep up! It was madness! I could not believe how much more your signal gets out with that minimal amount of power increase. It was a blessing and a curse at the same time, I now see why people will computer log in the field and have a helper to log for them so they can keep up. I could have easily worked 100 QSOs without trying hard if I had just stayed longer at the park. The SSB portion was on fire! The CW portion was doing fine too, but there were SO many more ops on SSB on this day…so many more… In the end, I had a great time and even worked my buddy Roger KG4WBI, this has to be my closest 20 meter contact for POTA ever. If I measured it right we were 2.9 miles apart. LOL What a great day to be on the air!

73

WK4DS

Classic CW Activation!!! Ten Tec Argonaut V for the win!

I don’t know if you have a favorite radio or not, but I do. The Ten Tec Argonaut V is one of my all time favorite portable CW rigs and for good reason! This radio brings all that is CW and Ten Tec together in the perfect combination of fun and ease of use.

Of course, this radio also has several other modes (although I could not tell you all of them as I have never switched it off of CW) but it will do other modes as well. All that said, it is a wonderful little CW machine and the ergonomics for use with CW show through in the design of the radio. From the minimalist layout to the proper location of critical operating controls, this radio is just about perfect. The only other thing that would make this radio even better would be the inclusion of Collins mechanical filters in the IF..but I digress… (Giving a quick nod to my Omni 7).

You see, when you’re activating a park with a small CW radio, you only need a few controls to be able to work the contacts coming in. The main two being the RIT for stations that are off your beat frequency by more than is comfortable (I had one of these today) and the filter bandwidth adjustment. These are the same knob on the Argonaut 5 and it is a simple button press to switch between these two functions. Another point to consider is these buttons are grouped near each other too so you are not searching all over the radio for the controls you need to work your activation. Along with these two controls the only other one I use while activating is the volume to bring down strong signals and it is also right next to the other controls, keeping the process really clean for me. Honestly the radio seems to be laid out with the “set-n-forget” stuff on the left side and the “active-use-while-operating” controls on the right now that I look at it.

Enough of me gushing on about the radio, we all know that I love this little machine…So onto the key and keyer. The key is my N3ZN travel key and it is fed into a HamGadgets Picokeyer both which are wonderful devices and work exceedingly well with the Ten Tec Argonaut V amateur radio. It has been a while since I have used the Hamgadgets Picokeyer so I had to get out the owners manual to see how to change one of the settings. Taking copies of the manuals is something I am a huge proponent of as it just makes sense. Without this book I would have been searching online, and sometimes that is not available at a park. The paper book never has a “dead battery” and is always ready to serve you. Take copies of the books with you…

A good cup of coffee is crucial to a good activation!

I went to my old haunt today US-2169 to get on the air and work some CW contacts as the space weather showed that the sun was still being friendly. I get to the park and find that it is starting to rain so I hurriedly setup my hamstick for 20 meters (I didn’t want to change bands alot with it raining…) and threw some electrical tape on the coax connector for a temporary rain jacket and got back in the truck. Pro-tip about electrical tape, turn it around backwards with the sticky side out and twist the end of the tape so it is easy to grab and unwind later if you don’t want the adhesive sticking to your parts. Things like the putting it on the coax connector as a temporarily rain shield is the perfect application for this idea. When you are done just unwind the tape and put it in the trash.

I had setup a new radial field design today as an experiment to see if adding a really long radial would work (or even help) and was pleasantly surprised to find it did! I really love using the nanoVNA to measure my antenna instead of a simple SWR meter, even though today I used the SWR function instead of the smith chart.

The power of the smith chart can not be overstated either. What you get to see on the smith chart is the data that the SWR plot shows (well, it shows the impedance and you have to know a little math to turn it into SWR) and is also shows you if your system is capacitive, inductive or purely resistive (the best option if you get to pick). Now this doesn’t mean your signal is going to get out to some distant DX station super well just because the SWR is 1:1, but your transceiver wont have to deal with reflected signals coming back down the line out of phase with the transmitted signal. I was a ham for way to long before I learned the power of the smith chart…and I have just scratched the surface of what can be done with it. All that to say that 1.061:1 is a great SWR for a field deployed antenna…lol

Just for fun I decided to look and see what the SSB segment would be since I tuned this antenna to center frequency on the CW portion and it is still good in this configuration. Dont let any SWR reading below 2:1 scare you, all radios are designed to be able to work into at least that much SWR as EEs (Electrical Engineers - the guys who actually design radios) know that these devices are going to end up in not-so-perfect applications and want them to work anyway.

The measurements, roughly, for these radials are 14’6” and 26’ respectively and they are laid out with the shorter one being 90 degrees to the truck. This is the position that I tuned the antenna at, with this radial as well as it’s mate running out the other side 180 degrees out from this one.

The 26’ radial is run pretty much away from the truck to the rear and it gets the benefit of running down the slope too. This angle adjusts the impedance of the antenna by changing the reactance. This is why discone antennas have the ground plane at 45 degrees sloping down, it presents a near perfect impedance to the transceiver. I will repeat this setup on my next trip and put the smith chart on it to see what it says about the system, I am curious to know now…

I keep this Ultra Picokeyer from Hamgadgets and the N3ZN portable CW key with the Argonaut V so every time I use this radio, I will have a memory keyer and nice paddle to operate it with. It had been a hot minute since I had used the Ultra Picokeyer so I needed to get the manual out for it. Seems for some reason last time I used it, I had enabled the internal tone (for use as a practice oscillator) and wanted to silence it for the activation. I knew how to get into the menu, but I didn’t remember the item name specifically, so out comes the book…

I can not stress how important it is to me to have the manuals to the devices I am using, stored with the kit. The only exception is when the device is so simple and intuitive that you don’t need one anyway (like with the Penntek TR-35 transceiver). So I keep home-made copies of manuals to both the Ultra Picokeyer and the Ten Tec Argonaut V transceiver in the hard shell case with them. They have saved me a couple of times already. Me and my friend KG4WBI (Roger) have this obsession with printing the manuals and then building them into these term paper booklets so we will have them later, I have so many manuals at this point, I have manuals for radios I no longer own…lol.

The 20 meter band was actually really good today. There is supposed to be significant solar problems right now as a problematic sunspot is pointing our way but I was graced with a little time to get on the air and was greeted with quite a few hunters to my surprise! As you can see in the beacon report below I was getting into New Hampshire quite well!

Some observations from today that I noticed were that I was getting states that I shouldn’t have been hearing… States like Alabama, North Carolina and even GEORGIA! I don’t ever get this kind of NVIS operation on 20 meters, I usually have to go to 40 meters to see this sort of thing happen.

Another thing was I was getting some pretty heavy QSB (fading of the signal) at times as well. The QSB even seemed to come and go which was normal to be honest for this sort of thing, but what made it unusual for me today was how deep it was. 599 signals would just disappear for 2 seconds the fade back in. Deep…

Fortunately I was able to get all the information for my log. There was a significant amount of US ops only on this day too. I figured there would be a few more Canadians as well but I only worked one on this day . It is always great to get some of our friends to the North in the log.

The diversity in the log spread today can not be understated. I was blown away with all those southern states coming back to me. Strange conditions for sure, maybe the new radial idea improved NVIS, maybe they have always been able to hear me and when I would activate there just wasn’t anyone hunting… I don’t know, but today they were there and I was stoked! Thanks for coming along and I hope to see you in the comments below.

WK4DS

Digital only POTA Activation using FT8 on the sBitx V3

So today was a good day for radio. I had a block of time and wanted to see how hard it would be to get the activation only on FT8. I know it is possible to do this, but I also wanted to do it on 15 meters too and that is where the problems come in. You see the last couple of weeks have been tough for 15 meters operations what with the solar flares and CMEs and all. So to secure the activation on the higher bands will be… interesting…

I get to the park and in the spirit of time savings I chose to go to Sitton’s Gulch which is significantly closer and saved me almost and hour of driving (well, 40 minutes as it is 20 minutes on to the operating position at the top of the mountain and another 20 back to the point at the bottom). I also was happy to see the parking lot was almost empty too. This gave me to opportunity to setup in the corner next to the changing sheds which is a good corner for my antenna radials. This gets them out of the way so that people dont trip over them going to and fro…

I set up in short order for the 15 meter band and get started calling CQ. I call for several minutes and then switch over to answering CQ calls that I see in the waterfall for a few more minutes with zilch to show for it. Literally nothing. I am starting to wonder if there was some sort of flare that I was not aware of or some such as that as I was getting stations into the radio but no one could hear me. I chalked it up to that they must have been running a kilowatt and my paltry little 12 watts into a compromise antenna just wasnt getting it done today.

One of the things that I like most about this radio is the clean layout of the FT8 mode. It is not cluttered with an endless array of different information and on screen settings. The other programs, while very versatile and powerful, are rife with buttons and information that really is not needed for simple QSO contacts. The sBitx could be a little easier though so it is not perfect either. One thing that has come up a couple of times is that it needs the ability to be able to sort the information display to just stations calling CQ so you can pick one easier. I agree with this as it can be tough to grab a calling station in that 2.5 second window of time. So being able to sort by CQ would be a big help there. One other thing that is mildly frustrating is that there is no way to scroll the display so if there is a lot of stations on the band then you will not be able to see them all. It pushes them off the top of the screen and then they are just gone.

Today though, there was plenty of room to see both even and odd stations so it was not a problem. I was glad to see there was a good amount of activity on the 17 meter band.

The truck cab sure it a convenient operation center for POTA!!! I find it almost perfect to be honest. It is so close that I have used it all winter without modifications but at some point I do think I want to modify it. I have been considering the Kenwood TS480 as a permanent installation in the truck just for POTA, but then I would still need either a computer or the sBitx to operate FT8 in thr fireld. This just circles back to using this radio like you see in the photo below till something better comes along.

Here is the antenna setup for today along with the nanoVNA I used to measure it while I “tuned” the system. Tuning literally involves just moving the radials around till the SWR reads as low as possible. Sometimes it involves adding another radial to the system to get the SWR below 2:1 (which is my personal high limit) and I have even done odd things like run one REALLY long radial way out to give the lower bands a chance at working. This has worked really well too when I want to use 40 meters with a hamstick.

To answer some obvious questions that will show up, yes, there are two nanoVNAs in the box…long story but I have two now. Haha. The case came from GigaParts as they had a bunch of them at the Huntsville hamfest one year for super good prices and I got a couple of them. This one houses the nanoVNA and multimeter and the other holds all my POTA radials. You can see it above on the truck bed cover. I plan to get more of these at some point as they are super useful containers for small equipment like you see here. That is why I wrote on the lid of the yellow one, plus it identifies it as mine as that is my handwriting too.

As you can see though, I had a pretty good run on 17 meters FT8, securing the successful activation just in this mode alone. I never like to stop at just ten so once I had worked everyone I could hear I moved down to 20 meters and worked two more there before calling QRT and packing up. 20 meters is the campground of POTA these day and if you want to simply claim a quick activation then go there, it should not take long to get your ten if you are pressed for time. I know some people do activations on their lunch break and 20 meters is great for that. If you want a bigger challenge though, move up to the higher bands. Seems here lately that when 15 meters is open I will work a ton of dx stations and the lower I go in the bands to closer to home the stations. So if you have not ventured higher in the bands, I recommend you give it a shot sometime, you will most likely be pleasantly surprised

WK4DS

Getting a quick activation in…

Today I wanted to get the whole activation on just bands above 20 meters. This means a lower QSO count than normal (most likely) and I am good with that. For me it is not about a high QSO count but rather time at the park (so long as I get my ten minimum of course…lol). So let’s get it setup and going. I only had two hours from the time I left the house till I had to be back at the house, so this pointed me straight to US-2169 since it was only a 20 minute drive for me. 40 minutes gone in driving only left me with 80 minutes to setup, activate and breakdown the rig, so I was in a bit of a hurry. I was really hoping that my usual spot would not be taken and fortunately it wasn’t.

Today also saw this little guy, pictured below, die on me. I went to check the SWR on my nanoVNA and it was really bad. It was so bad that it didn’t show the antenna to be connected at all, that is the worst kind of bad… So I start troubleshooting as this is eating my time and I was not wanting to lose anymore time than needed to setup. Well, I got lucky and as soon as I removed this from the circuit, the antenna showed up on the nanoVNA!.I just had to run without my usual common mode current choke in place, it could be worse, I could have a bad radio… Luckily I can easily get these from the internet without much issue. I also have a coax from ABR that has the ferrites on it but forgot about it at that moment or I would have simply ran it instead…

As of late, I seem to be operating from the truck cab more and more. Today was no exception either as it has a power cable hardwired, is in the shade (technically) and is easy to setup. I don’t want to just operate from here though so I am going to make a conscious effort to do things more diversified going forward… But for today, it was inside the truck so I could save time. Good thing I did too, the higher bands were…thin…to say it plainly.

So I start by hopping on 15 meters as the “weather report” looked good for the band today. Trouble is no one else was there from what I could hear. I looked and looked for a CW signal and saw nothing anywhere, I then called CQ for a few minutes to no avail as well. At this point I decided I would switch over to FT8 and get a few DX contacts in the log since this is where I usually do that… didn’t happen. I worked one person in Arizona and that was it! 15 meters was not doing anything today! Wow… what a reality check. I normally get a few, but just one is a new record for me here.

Well, once accepting defeat on 15 meters I begrudgingly moved down to 17 meters and found the band to be alive! So the MUF must have been 18.200mhz as I made a bunch of contacts on 17 meters in pretty short order on CW before switching over to FT8 to finish up the activation.

The park today saw a lot of activity and I actually had to share the parking lot with other people…I felt really odd having to do this. LOL… But really this location in particular is really good as it is in the middle of the lot which happens to be the least traveled location in the whole lot. There really isn’t anything that anyone would need that would require them to walk where I deploy the antenna. This is something that I look for now when activating a park. It is real important that you don’t leave a bad experience behind when you go to a park to activate it. This is one of those simple ways to accomplish this goal without having to spend any money or time on it.

The sBitx has quickly become one of my favorite radios to do this kind of operating with, Ashar has really done some out of the box thinking with this radio and it shows. I can simply make all the memory keyer memories I want, I can even make them for FT8 as well as CW and it is easy to edit, has no character limit, and is easy to find in the computer too. I just love how smart this radio is designed. I love the native FT8 mode, the ease of use in CW and how it is even a simple touch screen on top of all that…for 400$. That is hard to beat in my book.

Today also had a new thing happen to me. Look at the log and notice how I worked KC7AC on 15 meters with FT8 then when I moved to 17 meters I worked KL7AC on CW. At first I thought it was a typo in the log but the CW is unmistakable and the FT8 showed that call, which is almost like getting a jinx when talking to a friend or something. HaHa, I just thought it was kind of neat to see that and figured I would mention it at the end. I hope you get out and make some contacts today!

WK4DS

POTA Park Redemption

Today started out like any other day, but with better weather. I had recently had an activation that took almost 3 hours to net 11 QSOs and today I wanted a rematch!

Here is the post where I tell you how I was able to go out and in a more reasonable time frame, about an hour, I was able to get a little over 30 contacts in the log in two different modes.

This time I setup at the disc golf parking area and also had the place to myself, except for one park ranger who came up and mowed some of the grass on the far side of the parking lot and a couple of people that wandered through while I was there. This spot is a great location as it is at a high point as well as plenty of room to deploy radials and antennas. There are even a couple of trees nearby for a wire if you dont have a free standing antenna to use.

I forgot my regular logbook so I dug into the Penntek TR-35 go kit and got out the little notebook I keep in it to log with, this is the second time I have had to do this, so I really need a better system for my logbook…At least I had this to work with… I also love running FT8 too as it allows me to munch on some snacks while it is working for me in the background, here you can see my favorite snacks and I try to always have some of these in the truck anytime I am out.

The sBitx is a wonderful little radio running a Raspberry Pi for the brain so it is also a Linux radio and it is also open source, you can literally download the source code this radio runs on and edit it if you want. If you add a feature or fix a bug you find, you can also go on GitHub and submit these changes for a merge to the main code for everyone. There is a lot of features that I don’t even know how to use that other people are using to great effect with this little radio. It is really impressive. The biggest selling point for me was the fact that you can work FT8 on it without the need for an external computer or even supporting software like WSJTX or anything like that, just switch to FT8 and dial up the frequency and off you go, just like that.

Below you can see where I just finished working and auto-logging the contact with XE3BGM down on the Yucatan peninsula in Mexico. You can also see the spot page note where he respotted me and threw in his rig info too! Today saw a lot of DX stations in the log on 15 meters as this band works extremely well for me to reach Europe and the Americas and occasionally even Japan! This is native inside the radio on a touch screen. I just cant believe you get all this for what it costs! (Hint: it doesnt cost near as much as you would think it would, just go here and see for yourself).

Another thing I have figured out with the sBitx is that since it is a Raspberry Pi computer…essentially…that you can use computer peripherals with it. I know this is rather obvious but it is a novel concept for a ham radio. I have gotten to where I will bring a mouse with me to the parks now to make navigating the touch screen a little easier when operating from the truck seat.

This little luxury makes using the sBitx a wonderful little radio and I have really grown to enjoy it even with it’s quirks.

Since I was only going to work 15 meters only (at least that was the plan to start with), I only deployed the 20 meter radials as they also work on 15 meters better than they do on 20... This worked great on 15 meters with a near perfect SWR so I was off to the races! I hopped on FT8 to start with as the band was really active in that mode but CW operators were few and far between. This turned out to be a really good call and a lot of fun as I worked a ton of DX stations as you can see in the log below. Another thing I wanted to do was get this activation in before the solar storms hit on May 11th. This turned out to be a good idea too as the main storm was so strong that the Aurora Borealis was visible as far south as Georgia (I saw the orange/pink glow on the horizon that night myself). The space weather report below tells you everything you need to know about it from the screen capture below.

I love FT8 on 15 meters for the reason you see above. 8 DX stations (2 are Puerto Rico which POTA considers DX) but the band had some fading going on so I would get several then it would fade out for a minute then I would get one or two again, I then tried 15 meter CW but there wasn’t anyone around, after 10 minutes with no answers I moved to good ole 20 meters where I was able to work some CW contacts.

Once down on 20 meters a couple of CQ calls and it began! I was able to hear into most of the continental US and even worked Hawaii! Things were rolling good here too! I finally cleared all the callers at 29 QSOs and we all know one simply doesn’t stop on a number ending in 9 so I hopped on 20 meters FT8 and worked a couple of people there to get me to 31 for the day. All in all it was a great day for radio and I had a blast. I hope this inspires you to do something with radio soon, even the lowly hamstick is a capable antenna when it comes to POTA, I can easily get an activation in and be able to work many more stations in short order with them, so get out there and have some fun!

I hope you enjoyed following along today and hope to see you here again soon! 73!

SBitx V3 Radio goes to the park

Here we are again, my old friend the sBitx V2 (V3 now but more on that later) and a hamstick with about an hour to get an activation. Plot twist, the bands are terrible as there is a solar storm or something as you can see from the space weather report I captured from the time of the activation.

Just from looking at the above report, you would think that it would be anything but fun to activate a park… and you would be wrong as these reports, while handy for chasing rare dx in distant lands, mean very little for the POTA op, at least that is how it has been for me as a ham in the southeast United States. I have heard that in other places like out west, it is tougher as the density of operators is much lower, but if you live in the South, it seems that getting an activation in 2024 is pretty easy.

Today also saw me back inside the truck due to impending inclement weather conditions as you can see in the photo above. I wound up taping up the antenna connector to reduce water entry and was fortunate in that it didn’t actually rain so all was well anyway. It worked out anyway as I had not charged the battery from my previous outings so I wasn’t sure of the level of charge and this radio demands more energy than my other QRP rigs anyway.

Today also saw the use of the “ratty radials” as I think I am going to start calling them. As they seem to work SO well like this for some reason… haha. I did only deploy the 20 meter radials this time as I was in a hurry and didn’t want to mess with bands that didn’t “produce fruit” readily like 20 meters does. It seems that the bulk of the CW ops are almost always on 20 meters. I have also noticed that the FT8 activity is also much higher on 20 meters as well so that was also a perk for me.

I really like how the sBitx gives me the flexibility to use FT8 native in the radio and with the “push” of a touchscreen button, I can switch to CW and work that mode as well. It also allows me to use a regular mouse (if I remember to bring it) as well as just using the touch screen. Lol

As mentioned earlier my V2 has been modded to the V3 specs by changing the transmitter finals and updating the support circuits to bias them properly. The changes are pretty simple and it works great. I have mine biased just a little on the hot side and currently I am getting 50 watts of 80 meters(it actually produces more but I don’t want to push my luck here with over heating the transistors so I back the drive off to 50 watts as seen from my shack wattmeter in the photo above…) and 30 watts on 40 meters which is incredible for such a small radio. It has lower outputs the higher you go in the band due to the circuits being optimized for the lower bands, but it is still enough energy to make contacts with ease.

I also wanted to make sure that FT8 wasn’t going to cook the IRF520s like it did the old transistors so I setup in the shack and proceeded to work FT8 at this power level for many hours and on several days all with perfect operation so I am confident to take it to the field.

Today saw my SWR running about 1.5 : 1 so the radio was outputting about 15 watts on the display (this is actually about 13 or 14 as the meter on the radio needs recalibrating since the update). If the SWR is lower it will run as much as 22 watts on 20 meters under the current conditions.

I got on FT8 while I started getting all my paperwork ready and such, this is a benefit to me of FT8 in that I can be working QSOs while I am also doing administrative tasks at the same time. It basically allows me more air time instead of having to do the admin stuff then go live with the activation. Well FT8 was going so good that I just kept going with it! The QSO rate on this mode is a little slower for me as I am not really proficient with the mode like others are, but I can pretty consistently make a QSO every two minutes or so and this is fine for me as I am not one who wants tons of contacts anyway.

Also, check out the cool DX station from Mexico as well as the special event station I was able to work once I switched over to CW! it is always fun to work stations like these two awesome contacts above and beyond all the cool cats I worked otherwise as well! With less than 20 calls in the log, this is still one of my more favorite activations. Terrible band conditions due to a solar storm, worked two different modes and made a bunch of contacts…what more could you ask for?

Thanks for following along on my antics and I hope you come back next time.

WK4DS

Vintage gear is sus…

When you buy older radio equipment, it is a good idea to check inside before getting on the air with it as this article details about my Ten Tec 277 Antenna Tuner. Sometimes things are lurking inside that neither you nor the person you got it from know about.

I have had this tuner for over a year and have done park activations with it. The 277 also sees extensive shack lately with radios like the sBitx and Penntek TR-35 and such. I had noticed the other day that the sBitx was exhibiting some odd behavior on transmit and when connected directly to a dummy load, it acted normal. So I pulled the cover off of the tuner to have a quick look inside and this is what I found.

These two photos show both problems I found inside when the cover was removed. The first thing I saw was this burnt resistor, which goes to the SWR meter circuit and the wires were broken on the balanced line transformer.

Fortunately for me, neither of these actually impeded performance in how I used the tuner except maybe from arcing on that transformer where the leads were broken if it was still close enough to enable an arc... Probably not though so I am not sure there. The resistor is the 68 ohm resistor on the print that I found online. It looks like it is a simple load resistor to allow the diodes to sample from and was probably overheated by pushing a little too much RF through the tuner at some point in the past. With 86mA of current flow through this resistor, you are at the power limit of 1/2 watt. Doing some simple ohms law, that turns into 5.848 volts across the resistor. I should count the turns on the transformer to see what the primary voltage would have to be to make that happen… lol. That is a whole different rabbit hole though so let’s continue.

When I found these things I decided to go to the internet and see if I could find a schematic of this tuner. Well, the internet did not disappoint. Below is the schematic for this exact tuner.

The bottom half of the page is the schematic for my tuner as it has the SWR meter circuit in it. I printed out the schematic so I could have it on the bench with me during the repair process.

Something I have noted about Ten Tec prints, they lack critical information about things like the transformer ratio or the turns count on the tapped inductor on the matching network or even the turns count on the balanced line transformer, or even the rating of the little meter movement, none of these are present on the print.

To replace the resistor properly involved having to remove the circuit board from the tuner. This involved having to remove all the knobs as well as desoldering several wires to all the board to lift out of the chassis. I will take photos of the areas where I remove wires like this so it is easy to see how to reconnect them later. This is a bonus of the iPhone for me, it allows visual records to be kept in real time of things like this.

Once dismantled, I set out to replacing the resistor first. Sometimes the power rating of the component is just as big of a factor as the value, and I didn’t have a 68 ohm 1/2 watt resistor in my parts bin. What is a guy to do? Well, it turns out that if you put two 330 ohm resistors and two 220 ohm resistors all in parallel that you get 66 ohms mathematically. Mine measured out to about 65.7 ohms or something like that and so I added a 2.2 ohm resistor in series with the other four and BAM! 67.86 ohms! .002% accuracy is good enough if I had to guess, and I upped the wattage rating to 1 watt as well since the four higher value resistors are all 1/4 watt each and they will bear most of the burden of the power dissipation work anyway. (Probably a little less actually since more current will obviously flow through the 220 ohm resistors than the 330s but it will still be way over 1/2 watt total capacity now…) I put it together like you see so it would more easily fit the hole spacing on the circuit board as well as stand up the four parallel resistors to allow better heat dissipation.

Once I had the new resistor installed, I remounted the circuit boar5d and proceeded to reconnect every thing that I disconnected. This is also when I decided to rewire the transformer to the balanced like connections on the backplane as well. With all that done, I reinstalled all the knobs and was ready to test it out.

One last thing I did was tuck the print inside the chassis so that next time who ever is in here will have the information I didn’t and will be able to solve their problems that much easier. Kind of a gift to the next generation as this thing is really robust to be honest about it.

All buttoned up and ready to go back into service in the shack. Thanks for following along on this little adventure.

73

WK4DS

Tire station…

Today saw me wanting to go activate a park as the weather was wonderful and I had a little time to go so I headed over to my usual location at US-2169 (Cloudland Canyon State Park) and went to the frisbee golf course parking lot. But then as you see in the sign below, it says Ascalon Trailhead… Well, read on to see why.

Meet N4ARV (Anthony) who was setup with his FX-4CR portable station. He had already strung a nice long wire up into a nearby tree to work some POTA SSB in my usual spot! We chatted for a few minutes and we agreed that since I also wanted to work 20 meters (he was already on 20 at this point) that I would head over to the Ascalon Road Trailhead to prevent our radios from overloading each others receivers. I could have probably just went down to the canyon rim lot, but I knew Ascalon would be quieter so I hopped in the truck and was on my way.

Anthony had a really tidy little kit that he was operating out of today, the battery was really small too. It was right up my alley… haha. Just what I need, another radio…The FX-4CR is a powerhouse of a machine too. It is loaded with features that would make a full size radio blush! He was working SSB and it looked like he was not struggling at all either. Hope to meet him again at some point.

Once you get to the Ascalon Road trailhead, you are greeted with a little reminder to pay for your parking. I am exempt from all this mess though as I buy the annual pass, which for a POTA op, is worth it’s weight in gold since you will be in parks all the time.

I think I have activated 42 or 44 Georgia parks so far on this pass. If I had used the kiosk each time that would have been over 200 dollars in parking fees. Instead I have my annual pass which is only 50$ and my renewal isn’t till July. Last year I got over 100 activations on that pass making average parking costs only 50 cents per visit…not bad for what you get access to.

As you can see below, I pretty much had the place to myself. There were a few people that are behind my truck and are out of camera frame, but midday on a weekday is when I like to activate as you get the run of the place for the most part. I found a shady spot and parked there so I could setup on the bedcover, but as it turns out, the truck was on a slope that made the shady side about 5 feet off the ground. I knew at this point that I had to get creative with the radio location. I have setup like this once before already and I think it was with the same radio too, but today I setup with the whole little mini-station and it still fit!

Meet the “Tire Station” location of my POTA setups. I only have about 4 locations that I use. The truck cab, the bed cover, a random picnic table (basically I will use any available picnic table) and the “tire” station. I don’t think I have setup anywhere else in over a year other than these four positions. It works well with a folding camp chair, which I keep in the truck. It is also at the perfect height for my CW listening operations so I don’t need headphones as long as the rest of the area is still quiet.

Today also saw the introduction of a new piece of kit for me. The aviator knee clipboard… This widget is the perfect tool to hold my notebook and I could even stand up and get stuff out the pack or what ever and it would stay put. That was awesome to say the least, and is a great addition if you paper log like me. I don’t know how I got by so long with out it now that I have it.

As you can see, the clipboard make a little table of sorts that I can sit my stuff on and still work with the radio and such. I highly recommend this device for POTA ops. I got mine for Christmas, but if I had to guess, it probably came from Amazon… Just don’t forget that this “table” is attached to your leg and if you stand up, all the stuff on the table will go for flying lessons immediately.

I have memorized what the four knobs control, this frees me from having to look at them to control what they do. First knob is keyer speed, I use it to slow down for slower ops mostly, but I usually set it by ear anyway so I dont have to see it. Second knob is RF Power and it is set and forget, I dont change it during the activation at all. Thrid knob is RF gain and I use it to control the noise floor, I will usually turn it down a little to lower the band noise, but will turn it up to work a weak station. The last one is AF Gain (AKA Volume) and I use it a good bit, mainly when I get a really strong station coming in, I will back it down a little then, and then bring it back afterwards. But I use three of the four enough to memorize what they do so I don’t have to look at them. That is a huge benefit to such a simple radio, you simply memorize what each button, switch and knob do and you can operate the radio in the dark. I could run this radio blindfolded. I don’t think it will transmit out of band so I am pretty sure I could literally operate it blindfolded…only problem with that is then I couldn’t log…lol.

Another little addition to the radio that I really like is the S meter I built for it. I am thinking about changing the way it connects currently though as it needs the 3.5mm socket on the same side as the 4 pin plug. This would help tremendously with the arrangement of the little station at times and I really need to do it soon…lol. I also need to rework the power cable on the power box/speaker unit to be a little longer too, I dont know why I made that cable only 6 inches long.

Today saw a great run on 20 meters in the time I had allotted for the activation. As you can see below, I made 29 contacts in about 45 minutes at QRP power. Not bad for me. I enjoy the challenge of using small radios at these parks to make contacts like this. I will occasionally use larger radios too, but this is my jam…

I hope you enjoyed coming along for an activation with me and hope that I will work you on the air at some point.

40 meters QRP is FUN!

Today saw the introduction of my newly acquired 40 meter QRP CW radio that I picked up at the Orlando Hamcation. Read on to see what I think of this radio and how the activation went.

A quick over view of the radio. The transceiver is built by a silent key (W9SR) and I purchased it from the estate. The first thing you will notice is that it has no obvious numerical display except the ten turn potentiometer in the center. This is in fact the VFO or most likely the VCO if I had to guess. I am guessing as I have not dismantled the radio and really dont want to risk breaking it since it is a working machine currently. I can guess this though as it is a resistor and a resistor will allow you to vary the voltage easily on a varactor diode creating a Voltage Controlled Oscillator.

The next thing you will notice about it is that it doesn’t have any labels for the controls. At first I was worried about this, but then the fellow who sold me the radio showed me that there was a legend card included with the radio which has two critical pieces of information on it. The first is the chart that shares the value correlation of the potentiometer with the frequency of the radio output. The next thing it shows is what all the knobs and switches are used for on this little radio.

I decided to use this radio as I had a chance to activate a park earlier than usual today so I grabbed it and headed over to US-2169 (no longer K-2169 since the POTA people had to update all the parks due to the increase in activity and such with the program.) Heading over to the park I also took the Argonaut 5 kit as it has some keying gear in it I wanted to use. This turned out to be a good call as I could not get the SWR to pull down on the antenna today and I ended up adding the tuner that is also in this kit. This allowed me to add some inductance and get the antenna system to a nominal 50 ohm impedance match to the transceiver output as well as pull it to the center of the smith chart for an almost purely resistive load as well. The nanoVNA is invaluable for seeing things like this and it is why I like having it in the field.

Once at the park, I went to my usual spot at the frisbee golf course parking lot and proceeded to set up the system.

As you can see from the photo, it was really crowded today and I had trouble getting around all the people to setup my antenna system… lol. Only one park ranger and one truck passed through the lot during my whole activation, I was a little surprised by this as the weather was nice and there was a bunch of people down at the canyon, so I figured there would be a bunch playing frisbee golf too, but there wasn’t.

I have had trouble with my 40 meter hamstick the whole time I have owned it. This problem comes in the form of high SWR and I can only surmise it to be because there is not enough counter poise. I put out what I though to be enough radials and checked it and found the SWR to be 2.5:1 which is outside my personal limit of 2:1 so I added another radial from my kit that is usually for another band and checked it and it was a little better, but not great…maybe 2.1:1 or something like that.

So then I thought I would do something out of the ordinary and took my 17 meter radial set (it is one wire but it has a tap in the center with a STA-KON connector to attach it to my antenna mount). This in itself is not unusual, but the way I deployed it was. I figured I would make a single LONG radial out of it instead and see what would happen. Wouldn’t you know it, it helped ALOT!

You are seeing that right, it has a clove hitch tying it to the tree branch. Maybe that helped a little, I don’t know at this point. But I decided at this point to do some experimenting where I remembered in the past something about curtain dipoles and how you could drop a line down from the horizontal and it would change the antenna. I had some little gator clip leads in my nanoVNA kit so I grabbed one of these and clipped it to the STA-KON in the middle of the line and it made a difference too! Nothing extraordinary, but it did help so I left it. Checking the nanoVNA on the smith chart showed I had a good 50 ohm impedance to the antenna but the system was capacitive so I added the tuner so I could balance this out and get a clean load presented to the radio as I don’t want to burn this little guy up on the first outing. I ended up with a total of 5 radials put out to get the antenna and radio happy today and it looked ODD to say the least. I normally will run one or two at the most, so this looked like a spider web… lol.

I had intended to setup on the bed cover today as the weather rwas pretty nice to start with, but by the time I got to the park the wind had picked up to the point it was out of the question to try to hear CW with the radio fighting wind noise too. Because of this I setup inside the truck again and this made it easier too as I could just plug into the truck and go. So the station look like what you see below today. The N3ZN key and the Hamgadgets keyer into the W9SR 40 meter monoband CW transceiver and out of it into my little MFJ antenna tuner I keep with my Ten Tec Argonaut 5 transceiver kit.

Now, something about this little radio that is cool and most new comers to the CW corner of ham radio wont know about. This radio has relay keying. And the relay is kinda loud. It is almost comical with today’s diode switched radios that are silent and FAST. This little radio is far from a full QSK machine, but it works well none the less. I only missed a letter a couple of times and had to get a repeat to confirm it. Not bad for a radio that is probably built in the 1970s if I had to guess.

Another thing I have noticed about me lately is that I am drawn to this kind of radio more than the big box machines. I have owned some impressive radios in my day to include a Kenwood TS-950 SD, Ten Ten Omni 6+, as well as a Ten Tec Omni 7 and anybody who knows CW rigs, will know that these are all stellar CW machines of the highest order. These radios work so well that to work stations becomes almost no challenge at all. I have easily worked a metric ton of ops over the years on these radios and have loved doing it, but in the end, QRP really brings a challenge to the table that these machines cant. I know I could simply turn down the power of the bigger rig and sometimes I do, but these don’t travel well and besides it is just fun to use the tiny little machines.

Here are a few more photos of note about this radio before i I close out the showcase. It came in this ballistic nylon rigid pouch that holds it perfectly. Also I changed the ancient Molex connector over to power poles as I could not find a molex to fit it and it even how a 9 volt socket on the back that I am guessing is for some sort of accessory that is no longer needed… maybe a keyer like the Ten Tec keyers or something like that possibly? Who knows, but it is a great little radio.

As for the activation itself, I never have a bad outing, either it is good or better. Today was a good day. Any day I can make contacts is a good day to me. I made 13 contacts kind late in the day for 40 meters to be honest and to also only be using 3 1/2 watts too also made it a lot more sporty. There was a good bit of band noise today so most signals were weaker than usual, the radio did well though in that I could pick out even the weakest signals and was able to work them. I was impressed to say the least. I will be using this radio more if for no other reason than nostalgia. I love it and if you are into CW, you probably would too.

Thanks for following along today and I hope this blog post inspries you to get out and setup a radio. Until next week, 72 and GUD DX

WK4DS

I have a Penntek TR-35 QRP radio and it keeps growing...

So in this installment of how do you make a tiny, compact QRP radio MUCH bigger, I set out to add an S meter to the system! Now were talking!… or maybe more accurately were using CW … since it is a CW only radio. Anyway, I have been wanting an S meter for this little radio for a long time and then when the ham who invented this radio came out with the next generation (TR-45L) it had an S meter!

Pictured above is the new S meter and beside it is the power pack/speaker assembly, and in front of that is the Penntek TR-35 radio.

Now to be fair, I do have this radio kitted so that I can travel with it very efficiently. I have a kit that has everything I need, but nothing in the way of “frills” and this kit works great. It is small enough to pack in my carry-on bag and even has a power pack too. (Not the one pictured in the blog post but a smaller AA battery tray that holds 10 batteries.)

When I set out to add the S meter to the kit, I started looking for something small that I might could build directly into the radio housing. When I looked into how the radio is actually built though, this turned out to be less than ideal. You see the radio is one circuit board and it is connected to the front panel with ALL of those switches and knobs! Who wants to do all that work for a simple S meter install??? Well, as it turns out I would be that guy. The build to add the S meter as a stand alone part of my little kit was a lot more work than I thought it would be and then there was the trouble shooting and such… lol. Such is life and I now have a really cool, vintage S meter for my tiny station that I am putting together.

The S meter project I chose to build is brilliant to be quite honest. I am not sure who designed it first but I found the schematic on SeekIC.com and proceeded to build it based on this print, substituting parts as I needed due to what I had at hand. Since I did this, it took some experimenting to get the meter to read like I wanted as the final amplifier stage needed the gain adjusted and since I didn’t have a pot big enough, I had to swap resistors till it worked… but it worked. Sadly, I didn’t document the build at all, nor did I bother to even take photos of the internals for some reason, but suffice it to say that I am happy with the result.

Below is my heavily noted printout of the circuit from SeekIC.com. I initially built it without thinking about what was happening and it worked very poorly. This is my fault as I should have looked at the circuit more closely and realized what was going on and that I was misreading things in several places. The three resistors that have the arrows now have the decimal drawn in them. When I first printed the schematic so I could take it to the shop to build it, the decimal points didn’t show up and this meant I thought these resistors were 10 times larger values that what was supposed to be in these locations. This made for some really strange wave forms and the output only going up to .2mA on the meter with VERY strong signals on the radio… I knew something had to be wrong so I started looking at the circuit and figured I had some trouble from my substitution of the two transistors so I looked there first. That was when I noticed the voltage divider for the base of the 2N2222 (this is what I used instead of the 2N4401) was way off for a simple emitter follower amplifier. Then I really looked at the print and realized the number spacing was different on some of the resistors. Like the 15K and the “16K” which after looking more closely was actually a 1.5K… Then I went around the print and found two more like this realizing that I had this thing setup to fail right out of the chute. Back to the shop, modify the resisitor values in these locations and try it again.

That fixed the low output part, in fact, now I had a lot of output, ALOT! So I once again looked at the amplifier stage and decided to lower the gain on this amplifier from 12 down to 2.18 and see what happens. This worked, but I did overshoot the target a little so I went back and changed it to a gain of 4.3 by using a 560 ohm resistor on the emitter of the 2N2222. This seems about perfect for this little setup now with really strong signals giving full scale deflection but most running in the middle of the scale.

Also of note is that this is a vintage Westinghouse panel meter that reads up to 1mA… So this meter doesn’t load the circuit hardly at all. That was the main reason I chose it. Enough with the new S meter project though, let’s go to a park and put it on the air!

Today I went to Cloudland Canyon (K-2169) and setup by the canyon at my favorite table when the weather is nice. Then I strung up my Reliance Antenna 40m EFHW and connected it to my radio with a piece of ABR Industries coax. Before hoping on the air though, I put another of my recent projects to use, the QRP Guys SWR/Wattmeter kit. I built out the small kit for it with a water tight storage box, a small BNC coax jumper and the instructions should I need them for some reason. It runs on a simple coin cell and works like a charm. It is a great kit if you are looking for something that will handle up to 10 watts like I was.

This thing is a breeze to put together, even the little toroid transformer was pretty easy to build actually. So don’t let “winding a toroid” hold you back, it isn’t that tough to do and the reward is totally worth it.

I checked the antenna and it had less than 1.5:1 SWR on 40, 20 AND 17 meters! I was stoked to see 17 meters was also good to go. This must be something to do with the 20 meter bandwidth, I should have taken the nanoVNA with me to the table (it was in the truck) but I didn’t want to spend a bunch of time on it. I wanted to get on the air and make some contacts!

I have really come to love these cable built by ABR Industries out of Texas. They make all sorts of cabling, but for me, these with the common mode choke built into the cable is a god send. It allows me to simply put up the antenna without worry of RF getting back into the radio and causing me problems from my… less than perfect… antenna installations. When activating POTA parks there is not always a perfect place to install an antenna so you end up with all sorts of stuff on the air and it is possible to have poorly matched impedances on your antennas. The ferrite beads help keep this problem to a minimum.

This little antenna is actually quite long. Approximately 65’ (give or take as I don’t remember right off) and I strung it up into the tree in the photo below. I am pointing out the location of the end where it went to the tree from where I threw my line. It also started at the “radio end” about 15’ off the ground as I strung it over a tree limb at the table to get it off the ground. This puts the whole antenna elevated above the grade somewhat and I want to say it helps as you can see by the logbook below.

60 contacts in one outing, QRP, with decent band conditions will fill your heart with joy. This was a fun afternoon and I plan to do it again soon.

72

WK4DS

Sometimes it is nice to have a slower day

I recently setup an activation at K-2169 and had no where to be for the rest of the day… This is my kind of POTA activation!

The above photo is a little misleading, there was one other car in the lot, but due to camera angle and me wanting the truck to be in the frame as well as the parking lot it is out of view. But it was essentially empty, so it was really quiet and I didnt even see a park ranger on this day, they normally ride by once or twice while I am setup and sometimes they even stop for a chat. I have been here so much that they know what I am doing and are cool with it. I contribute this to the fact that I am in a corner of the property where there is little to no activity most of the time, I don’t consume more than one parking space with my setup, I stay out of the pavilions (I have used them in the past if they were not being used and had no placard reserving them), my setup doesn’t involve me driving stakes into the ground and I do my best to keep my footprint to a minimum. Since I use CW for the most part, I don’t make very much noise either so it is minimal impact all around. At least that is my perspective and it seems that it is also the park employees perspective as well…or they could just not care about the old codger over there with the little radios…lol.

Today saw me on the 17 meter band with Morse code and it has always been an intriguing experience. The rhythmic sound of the dots and dashes echoing over the airwaves brings a sense of nostalgia for a bygone era while honing my skills in communication and technology. Despite the advancements in digital modes, Morse code offers a unique challenge that is both rewarding and intellectually stimulating. Operating on the 17 meter band allows for reliable long-distance communication, opening up a world of possibilities to connect with fellow enthusiasts from different corners of the globe. (Check the log and you will see what I mean by waxing nostalgic) It's fascinating to see how a simple yet effective mode like Morse code continues to thrive in the modern age of ham radio.

Below is the whole station (minus the S meter I am currently building for it) for the TR-35 HF radio. I have built the “black box” of options to help complete out the radio, the box has a battery pack in it as well as a speaker for the radio since it has no speaker of it’s own and I have added a push button to activate the voltmeter so it doesn’t run constantly and drain said battery. There is also a power port on the front now to allow the connection of two accessories as well. (This is for future expansion of the kit to include one more item that I wished this radio had built into it, an S meter)…

I created the box with the cabling to connect it to the Penntek TR-35 radio and it makes a station out of it basically. Just add your favorite CW key and you are off to the races.

I really like the layout of this radio, if I could alter the design at all, it would be to add two pushbuttons to send the CW memories with, but that is nitpicking to be honest. One other thing is that I like to have an S meter for some reason, it is fine to operate without it, but I just like having it for some reason… The system works well as it is and once you use it for literally a couple of minutes, it is easy to send the memories. If you are into small CW radios, this is one to have in my opinion…

Another thing I like about this radio is the fact that all the controls are on the surface that you need when operating. I like that it has the four knobs at the bottom and i usually use all four of them in an activation! Come to think of it, I usually use EVERY control on the radio on every outing… Everything you need and nothing you don’t…except for that S meter… HaHa. Another thing I like about this radio is the size. It is so small that it fits in my hand (for the most part) and is a 4 band CW transceiver! Even though it doesn’t have an antenna tuner, this is still a huge win for me. It sold me almost immediately when I took it to the field. That was when I realized I had found the replacement for the Elecraft K1 that I had used for so many years..

What your going to notice about today’s logbook page is that it doesn’t have very many calls in it. There is a couple of reasons for this. The first one is that the band was fading in and out pretty heavily. Just look at the time stamps on the RBN reports below and the associated the dB levels at those times, it was up and down heavily. Now I understand these stations are scattered around the country, but they are all west coast for the most part ( a feature of 17 meters is it skips over the closer states for me on my hamstick) and they show an amazing amount of variation in signal in just a few minutes of time. Once I looked at this, I realized I just needed to call and when the band would open up I would get two or three and then it would close back down, call a few minutes and get a couple more…rinse and repeat. It was still a lot of fun and I work Japan in one of the openings too!!!

Just check out that one lone DX contact from Japan! I was blown away when I heard his callsign coming into my tiny little radio. I love these kinds of days just as much as the faster paced, high QSO count days. It is just fun to setup a radio and make contact with distant stations whether in my own country or half way around the world.

Thank you for following along on my little journey to a local park, I hope it inspires you to get on the air and make contact with someone out there.

72 WK4Ds

Broke out the Penntek TR-35 for a change.

When you dont use a radio for a while it is almost like having a new radio…

This radio has quickly became on of my all time favorite radios. This tiny radio has everything you could ask for in a CW machine…EXCEPT for an internal antenna tuner…but I digress. In the past I have had the Elecraft K1 (a couple of times actually) which does have a tuner (both of mine had the tuner) but it was not as intuitive to use. That is why I sold it and got this one instead. It is a better radio in my opinion… Even missing the antenna tuner, I prefer this little radio to the K1, now this comes with some needed caveats as it is not really fair to compare these two radios directly. You see the K1 was design around 20 years ago and the TR-35 my more recently with much more modern technology and features. The stability of the TR-35 is uncanny compared to the K1 which would drift a little till it warmed up. Still the K1 was a wonderful machine for my needs and I used it to activate a POTA park on the island of Hawaii last year, so it is plenty capable.

Due to the weather improving I have moved the “shack” outside and setup on the bed cover to get some sun and fresh air, plus it is easier to work since I can spread out the gear somewhat.

I like these hamstick antennas so much that I am thinking about making a tripod mount for them so that I can setup at a nearby picnic table and use them with an elevated counterpoise concept… I could even get them higher above the grade this way too, possibly improving performance a little.

So this is the whole station today, the hamstick on 17 meters with a 15’ coax to the common mode choke. I put it on the nanoVNA and the resonant point was high, and I think it is from the fact that the 17 meter counterpoise wire have some broken off of them which makes them too short for a tuned circuit. But nonetheless the SWR measurement was plenty good enough to use, so I got on the air in short order. To try to compensate for this, I added the 20 meter radial that works so well for me now in the past on a bunch of bands. (I should probably measure this wire and make a new since it is getting frazzled) but it didn’t help very much today. I left it anyway as it did seem to help a little…

The operating position today… I really like using the bed cover for the operation position as it affords me the most user space I could possible imagine as well as it is simple. I have activated with this battery 3 or 4 times at this point and it is still over 13 volts!

The key for today is the Gemini travel key. This has turned out to be a wonderful little key and I am so happy to have bought it. It works so well.

As you can see from the log, I had a great day on 17 meters and even landed me a DX station! Jan was in the Netherlands when I started hearing his callsign! It was awesome that he could hear me too!!! There was some fading of course, but he could hear me! I made a good bit of notes about the activation in the log today where you can see things happening like when I lost a QSO outright to some one tuning up on top of me…for a long time… There is another note about the time when someone had a messed up car ignition that created some broad band noise and I couldn’t hear anything for a few minutes till they left.

Quickie CW Activation

Let’s goto Cloudland for a break from troubleshooting a radio. I have been working on this Ten Tec 6 meter FM machine for a week or two at this point and finally redrew the oscillator circuit so I could more easily understand the point of all those varactor diodes…

After studying this for a while I decided to get on the air with a different radio and have some fun with CW. I didn’t have a lot of time so I decided to goto the Sittons Gulch parking area of Cloudland Canyon State Park (US-2169) and setup inside the truck. The parking area was packed on a Friday morning and I almost didn’t get to setup here!!! So much so that the only available space was next to the entrance on the shoulder of the road. You can see how close I was to the gate in the photo below.

Here is a special trick I figured out too. The one radial I cut for 20 meters and then subsequently was broken and twisted back together…(making it short for a resonant antenna on something just higher than 20 meters…). This poor radial sees so much use, I really need to make a new radial wire that is this length but without the broken spot. Another thing is that it also works with my 17 meter antenna too. So one radial works on two antennae!!! Sweet!!!

Today saw me using the Penntek TR-35 QRP CW transceiver and none of the extra widgets I have been using. Headphones are needed since it has no speaker of any kind. Another quirk with this radio is that it is wired from the factory for a mono headphone connection (this is user adjustable by dismantling the radio and changing the connector wiring physically) so I need an adapter to be able to hear the audio in both ears. For DC voltage requirements, I simply plugged into the truck power cable I recently installed and I was off to the races!

If you look at the log sheet, you will notice I started 11 minutes before I made my first contact. This is because I setup on 17 meters to start with and called CQ for ten minutes with zero answers. I finally learned my lesson and moved down to 20 meters where all the hams were located. Things immediately improved and I made quite a few contacts once I made the move.

I hope you have enjoyed this little excursion to my local park and seeing what I do when time is tight and also space is limited. Until next time, get out and get on the air.

72

WK4DS - David

WA4MCM SWR/Wattmeter

I recently added a new device to my shack for the QRP section. It is the WA4MCM SWR/Wattmeter and this thing is really cool. A little background about Don is that he started selling these on QRZ.com in the “Ham Made Gear” section and immediately sold out the first batch! I figured when things calmed down a little that I would get one then and it slipped to the back burner from there. Then I found him at Hamcation!

To be fair, this is intended to be a kit that you build and tune yourself. But I found Don at Hamcation and after talking with him for a while figured out that for a small nominal fee, he would build and tune it as well! Below is a photo of his display where he was demonstrating his remote antenna switches as well as his wattmeter.

Opening the box, you are greeted with a note asking if you liked everything (which is a nice touch) and then you have all the goodies!

Then the 3.5mm audio cable is the comm link between the sensor and the meter, then there is a stylus for the touchscreen. Next is the 12v 1amp power supply so you can power it from wall power if you want. I made up a simple power cable to plug into my powerpole strip that is fused and fed from a Ten Tec 20amp powersupply instead so I can power down the whole shack with one switch.

Next is the sensor, which is rated for full legal limit power, but is sensitive enough to go down to .1watt increments should you need it. Finally is the meter itself. It has a power switch on the back as well as the 12vdc port and the sensor port.

He has written an extensive owners manual that covers usage as well as calibration. It is not printed though, so if you want a hard copy like I want, you will need to print it out yourself.

The unit has two power ranges to choose from 20, 200, 2000 and 10, 100, 1000. To switch between these requires you to retune the meter so it is a thing you do not take lightly. I plan to retune to the lower settings at some point as this is going to stay under 1000 watts (my amplifier is only 400 watts anyway). But for now I am using it as the 20 watt version. I currently have it connected to my QRP station as I mentioned earlier and it works fine in this role.

This meter has several features I love such as multiple display options like an analog needle style display as well as the bar graph above and a simple large number numeric display if you are having trouble seeing smaller numbers. It also being a touch screen has a “sleep” mode where the display turns off after a preset amount of time you choose in the settings menu. To wake it up, simply touch the screen and it is back online. It is a great tool and I wished I had bought one sooner to be honest about it.

73

WK4DS

My hamfest "radio" adventure

Roger (KG4WBI) and I have basically been going to the Dalton GA hamfest for 2 decades at this point and this year was incredible as far as attendance and the sheer volume of dealers in the “boneyard”.

So as per our usual modus operandi, we decide to see how many Ten Tec radios are available and this trip we also have some other items we are in search of as well.

I personally was looking for the following:

• A high power dummy load

• A low pass filter

• A ten meter radio that has the CW mode

• A oscilloscope that works up to 150mhz

Of all these items, I found the first three! Score!!!

This blog post covers my ten meter “radio” part of the adventure.I found a President HR2600 10 meter radio for sale that worked perfectly and bought it for really reasonable money. The below photo is of the finished project.

The first thing I need to do is turn down the output power to 1 watt or maybe 2 as this radio is going to be a 10 meter beacon on 28.221mhz. So I search online and find out the control to adjust the output power in CW for this radio and then I open the radio to make the adjustment…

Once open, I am greeted with a cooked lowpass filter on the output. Seems one of the capacitors failed, caught fire and in the process, scorched the circuit board as well as burning the enamel off of two inductors… now what to do?

Simple, rebuild the filter section.

Another rudimentary search on google turned up a schematic of this radio. The three parts shown are what needed replacing in the filter but since the board what charred, I opted to build a separate filter module on perf-board and wire it down to the edges where the old parts connected. This way I could cut out all the carbon so it wouldn’t leak current.

It literally burned a hole in the circuit board! The above photo shows how bad it was once I had pulled all the components from the board in the area of the damage. That carbon is a problem too as carbon is conductive so if you dont remove the carbon or remove enough parts that it isnt in play then it will cause lots of problems. In the below photo you can see where I cut out the burnt board so it would not conduct. The ground trace broke due to this damage so I simply added a jumper wire across this area to tie it back together. I only did this in case there was a need for ampacity since the ground plane went all around this part of the board. This actually worked so now to get a working lowpass filter.

In the above photo I have marked all the spots where connections are required for the various detectors to work properly as well as the input and the output to the filter section. I ended up not connecting the detectors though since it is not receiving at all and is only transmitting a beacon signal on CW. I checked and it worked fine without these two connections so I simply left them out. Someone will find this radio in the future and think they have scored a treasure until half the detectors don’t function for some reason…lol.

Below shows a coil that had the enamel burned off of it that was sitting next to the capacitor…This part of the radio was technically functioning too (well, passing the RF at the least), since this part was simply a low pass filter after the final transistor, when it burned it simply shorted through and just kept transmitting, albeit without the filtering it was supposed to have, but it was functioning…

Once I had decided to replace the filter, I started simply remaking the bad parts from scratch and using existing parts that were good, trying to emulate the original design. This is where I ran into a problem. In my desire to simply repair it like I did, I ended up creating a lower frequency null that was completely shutting out the 10 meter band… It was a wide enough null that I couldn’t bend the coils and fix it either… (With coils this small, you can shift the null around a little by spreading the coils out on the inductors, but this was not enough to get it to work for me.) So I simply opted for what I should have done to start with, make a filter from scratch and tune it out of the radio with the nanoVNA before installing it…

Above is my attempt at replicating the old parts, I measured the core diameter and it was real close to 1/4” so I simply made new coils based on this and hoped for the best. (The lighter colored inductor on the left is original from the radio, I reused it since it wasn’t damaged.) To test my theory, I simply soldered a wire across the the input and output terminals of where the filter would go (see below photo), powered the unit on and it worked fine (the transmitter was still working as it should). This is what told me the tune on the filter was off frequency. When I put the nanoVNA on the filter it had a DEEEEEEP null right at 28mhz all the way down to 24mhz and up to 33mhz! Seems my replacement parts and their new configuration had lowered the low end of the filter to the point that I was choking off my own signal. Haha…

So here is the filter I scratch built. Side note here, the capacitors in my filter are all high voltage capacitors as the output voltage of the RF signal can be very high at times. It can easily exceed 100volts in some circumstances so I chose capacitors that were at a minimum of 500 volt rated and some are even more. Better safe than sorry in this regard. It has larger inductors which give me more room to adjust them. I used an online calculator to figure the beginning values. This worked great because I had a good starting point to work from. I then connected it to my nanoVNA and checked the loss on the S21 input to see the filters shape. Air core inductors are a funny thing, they generate a nonlinear pattern of suppression that has deep nulls and at some points almost no effect on signal. The photo above shows where I adjusted one coil a little to get the null to land on the 6 meter band and also this is where this 2nd order harmonic would also appear, if there was one (knowing the quality of the factory low pass filter, it probably has a harmonic…lol). This would suppress any harmonics that might show up and also it has decent suppression across the region as well. You can see in the photo below that I added some capacitors to the bottom as well to help with the cutoff and to improve performance of the filter overall.

I ran it through the nanoVNA to tune it so it would let me run the beacon. It was losing about 3.5dB of signal at 28.221mhz but that isn’t a problem for me since I only want 1 watt forward power anyway. I simply connected the radio to a dummy load through a good wattmeter and tuned the pot inside the radio till I had 1 watt on the wattmeter. That 2nd deep null is at the first harmonic which is the 6meter band so it is working like it should. The original filter worked about as good as this one from what the math says. Air core inductors are not great compared to toroidal inductors but they do work. The first null appeared when I added one of the capacitors on the bottom, I will take what ever I can get and this added some suppression to the filter so I left it. The calculator showed the starting point of my filter with the image below captured from the online calculator. The calculator I used took the size of the coil and the number of turns and the over all length into account to come up with these numbers.

I ended up changing the first cap to 33pF by adding another 100pF in series with the other two and I also added a 33pF across the center coil (as this was what was on the original coil and the VNA showed an improvement in filtering when I soldered it on so I left it), I am pretty sure this is where the second null showed up at and also generally improved the whole filter.

So all in all, this was actually a fun little project and I learned alot about filter construction and tuning at the same time. I have said it before and I will say it again, if you don’t have a nanoVNA, get one for this sort of stuff. It works really well and it is super cost effective compared to professional gear that does the same job.