POTA AAR using 3 modes on the sBitx transceiver

Today marks the second deployment of the sBitx and me using it on three different modes.

You see, I spent a good bit of time recently solving the weak audio problem with the SSB mode in this radio. I found the microphone input level is really weak and there was a common solve by installing a more powerful microphone element in the hand mc. I tried this approach and it really didn’t help much for me. l was still essentially still yelling at the radio to get it to work.pictured below is what my radio looked like on the work bench as I worked on the audio level for the microphone input.

I ended up building a pre-amp circuit to boost the audio several dB and this fixed my weak audio problem. Here is a link to that blog post in case you missed it and want to know more about this.

Back to the activation, it was a beautiful day and wasn’t really all that hot either. This is a nice departure from the July temperatures I had been dealing with recently.

I setup in my usual place but indexed the truck about 90 degrees so the sun wouldn’t shine directly in my open door. This allowed me to leave it open for the most part. I get so much more aurflow with the door open as opposed to just rolling down the window.

I also ran my 20 meter ham stick on the truck hitch mount I made and just deployed the two radials I tuned for 20 meters. I planned on this activation being kinda short so I didn’t setup for any other band since 20 meters is so active I should easily get my activation locked in on just that band.

I do have some future plans for the antenna mount though. One of thise is to incorporate multiple ham stick mounts (2 specifically) to allow for band hopping without having to get out of the truck. This way if I am setup on a rainy day, I can go ahead and setup two bands at the beginning and then just stay in the truck.

I am beginning to think I want to install a screwdriver antenna again like a Tarheel or something like that and just use that for the quicky ones. I have heard good things about Tarheel antennas and it would make a bunch of my activations so much faster.

I use these CB antenna mounts you get from the truck stops for my base connections. It is an easy way to build an antenna mount from scratch as it has everything you need to attach the antenna to the base.

Something else I like about the sBitx is that even though it is a touch screen design, it can also be mouse operated. This makes using the radio about 100 times easier as some of the touch functions can be fickle. Like picking a station to call on FT8 from the list. It isn’t super hard to do by hand but it is MUCH easier to do with a mouse. Because of this, I have started bringing a USB mouse with me on my activations.

Yet another reason I like this radio… lol. It can also use a USB keyboard as well and you can “type” CW with it if you want but I dont worry with that as I really dont have the room for the keyboard at this time. Maybe at some future point I will add a shelf for those items. Haha.

All in all it was a great activation and I really enjoyed the time at the park as well. It was really cool to be able to use SSB with this radio! That alone made this particular trip unique. I think prior to this that I had made just one SSB contacts total! ONE! Now that mode is going to be showing up in the logs more and more and I can’t wait to share those trips with you one here.

73

WK4DS

Working on the microphone input of my sBitx

This is what a project in progress looks like for me…

I have been hobbled by the low audio in my sBitx since it was purchased back in 2023. This radio is a godsend for FT8 but the SSB microphone level was almost unusable. It was weak and you had to yell at the radio to get it to work at all. I didn’t really want to go into the software and start changing stuff in it, so I decided to bring the level up by adding a pre-amp to the circuit.

So I get out a breadboard and build up a simple audio amplifier circuit on it with a 2N3904 transistor and set about to see what levels I could get with a simple 9VDC battery powering it and feeding the input with the actual microphone I plan to use. I used a couple of potentiometers to adjust the input level and the gain of the circuit so that I could tune it to work with my radio. Below is the circuit I found online (why go to the trouble of designing one from scratch when it has already be invented?) So I built it up and changed 10k resistor and the 100k resistor with the pots I mentioned earlier and it was time to put the scope probe on it and see what I got.

It worked beautifully well. I could drive it to clipping if I wanted but I had PLENTY of gain before that happened. Way more than I needed I would find out later when testing it on the air with my friend on 80 meters. I chose to setup the bench test by simply getting the board out of the radio and powering it without the Raspberry Pi installed, this would power up the audio amplifier circuit without the hassle of it biasing the RF section. I put a scope probe on C119 at the output of the transistor (which you will notice looks very similar to the one I built actually). This circuit powers up when the switch is turned on so you dont need to even have the Pi installed to work with this circuit. For testing I simply connected the output of my amp to the mic jack with jumper wires and then spoke into the microphone while watching the scope. It worked really well to be honest. It worked so well that I looked at the sBitx circuit and figured that full output was 3VDC peak to peak or so as there is a 3.3V zener diode on the input of the IC this circuit is feeding. 3.3V logic protection if what I am figuring and these zeners are clamping the signal to that voltage max for safety.

This was a mistake turns out as it needed me to dial back the input significantly to get good quality audio out of the radio, but I had signal finally! It worked!!!

The yellow trace is what was going into the mic input and the purple trace is what was coming out of the pre amp I built. I was well pleased with this. I then proceeded to move the parts to a perf board and install it into the radio semi permanently to test it.

In the photo below I am pointing at the little “daughter” board I built with my pre-amp circuit on it. I tapped power from the input right at the massive reverse polarity protection diode that I also installed in my radio. The factory diode is really small and if you didn’t consider a small enough fuse in your power cord or worse…no fuse at all, then it will burn open after a short time and will let the reverse voltage wreak havoc on your radio. The reason I know this is that it has happened to others with this radio. This diode, combined with my 10 amp fuse, works like it should. It will blow the fuse every time and not damage the diode. I tested the idea a few times with a few fuses to make sure it would work and it did.

Here you can see how I hard wired the amp into the radio. I lifted the end of the RF choke that was connected to the microphone port and soldered my pre-amp output to the inductor and then my pre-amp input is simply soldered into the through hole the inductor was in. This made for a simple and non-permanent installation should I want to remove my mod at some point. After this, I simply wrapped the board with a little electrical tape and zip tied it in place so it doesn’t wiggle around too much while I test it in the field some. Once I got the pre-amp tied in I realized I was “double biasing” the electrolytic DC blocking capacitor that I was using to couple the pre-amp to the amp in the radio. So I simply removed the SMD resistor RD21 as this resistor is normally used to power the microphone elements and I had my own bias resistor already in the circuit.

Here is what the audio waveform looked like on the radio when transmitting later after I got the radio put back together. Before ( I should have taken a photo…) it was barely visible when you would talk into the microphone. and it was showing power out too!!! Success was had the next day when I made two SSB contacts with it on a POTA activation.

I hope this inspires you to make some improvements to your electronics in some way, this was really fun and rewarding in the end as it enabled a mode on this radio that had been previously disabled by default.

A shorted diode…and the sBitx

I blew a diode while pushing the boundaries of my IRF520 output transistors messing around with FT8…

Troubleshooting was actually pretty simple this time as I chose to use technology to my advantage and simply scanned the parts during transmit with the infrared heat gun and found a diode was 25 degrees hotter than everything else around it. This has to be cheating…

Let’s rewind time just a little so you can understand what I have been doing here… You see, this radio came with some fairly fragile finals from the factory. So fragile in fact, that they sent a spare set with the radio. The IRFZ24N transistors were wonderful, but under full load on FT8 and into less than perfect SWR would prove fatal for them. I ended up killing 3 of them before changing my radio over to the V3 spec. The V3 specification changes the finals and also changes a few other components in the amplifier chain to use them properly. HF Signals sent out a bulletin showing what all needed to be done and it was actually pretty straight forward. I decided to use some IRF520 transistors instead of the IRF510 transistors speced for the update as they had better current specs than the IRF510. They are rated for the same power dissipation essentially, but can handle almost twice the current without damage. This combined with the fact that I had them on hand, led to the construction of a bomb proof set of finals in my sBitx radio!

Once I had them installed, I set the bias and was off to the races. They literally handle anything I throw at them and I have run them hard to make sure they would not fail in the field at an activation. This is good and bad you see, these transistors work so well that I now can get over 65 watts (with the drive set to 100%) on 80 meters with them…and this is a problem.

The sBitx is not engineered for transmitter output powers this high, the original design was for 40 watts maximum forward power. and the components in the amplifier chain are sized accordingly. I learned this when I powered up the machine after messing around on 80 meters and accidentally transmitted into a 10:1 SWR with it last night (probably infinite SWR since it was into the coax with no antenna on it... It blew the 10 amp fuse almost immediately, which I figured would protect the radio…and it did, sort of... I was able to put a new fuse in it and get right back on 80 meters without any trouble at all. I didn’t leave that band though so I had no idea what had actually happened.

Fast forward back to today, I turn on the rig and dial up 15 meters to see what was happening on FT8 there, tune up the antenna with the Comet Antenna Analyzer and the manual antenna tuner and I am off to the races! Or so I thought. Seems when it would go into transmit, there was zero watts going out to the antenna, but the Astron RS-35M power supply was showing proper current draw for 15 meters FT8 transmit! How is it pulling the right amount of amps (6 amps is 20 watts on 15 meters) and not putting anything into the coax? That math ain’t mathing… I remember that whole current law about current going in has to match current coming out, so I start looking around.

I tested 10 meters and it was the same, so was 20 meters, but when I got to 40 meters, suddenly I had power to the antenna again. I also had it on 80 meters as well, full output power was there till I left the two lower bands. Something is either wrong with the 80/40 section OR all of the others. So I take it down to the shop where my test bench is located and rig it to a dummy load to see what I could find with the heat gun.

The photo below shows the diode that is shorted where I pulled one leg, so I could test my theory prior to dismantling the radio to replace it properly. This is a 1N4007 and it is being used to switch the radio’s transmitter band pass filters into and out of circuit. It has four filters to cover 8 ham bands (80 & 40, 30 & 20, 17 & 15, then 12 & 10 is the last one). The diode that failed was on the 40 & 80 meter filter. This essentially turned it on all the time. and also turning off the others by putting the switching voltage on both sides of the other filters output diodes. This makes them all have zero volts dropped across them essentially turning them all off. So only the 40 & 80 meter filter could be turned on at this point. You can see what I am talking about by looking at the schematic below where I am pointing out the diode that failed on the print.

The foreground, in the below photo, is the board showing the new diode in place after removing all the stuff in the background to get to it. You have to literally take the whole thing apart to get to this part of the radio. Fortunately for me, I have done it so much I have memorized the process and can do it in maybe ten minutes. You can also see the two IRF520 finals next to my thumb, you can also see all the heatsinks I installed to help mitigate the heat buildup in the radio.

Did a static test on the bench, just to make sure, and it worked perfectly with the dummy load attached. Luckily I did it right and dont have to take that whole thing back apart! HaHa. In the background is another little project I may write about. Seems the sBitx has this systemic problem with low audio on SSB and I tried the new microphone element others in the email reflector suggested to no avail. So the next solve is a more “active” solution with the use of a small single transistor amplifier is a sort of (pre-amp) configuration so that I can increase the audio signal going into the radio and make it actually work like it should. The radio already has one of these circuits in it, I don’t think it can handle any more gain with out distorting so I want to pre-amp into it with a variable gain setup so I can go into it with 2x, 3x or even 5x the input signal so I can get decent audio out of my radio. More on this later…

Man, I had no idea how messy my bench was till I looked at this photo… I will have to clean that up! Sorry about that everyone…

So today had the real test. I took it to US-2169 and setup in my usual spot and decided that today I would stay on 40 meters till I secured the activation then I would move to 15 meters to see what I could find. Seem I found a lot. 40 meters and hamsticks will usually produce contacts that are closer to home for me, maybe as far away as Texas or Michigan is a long haul on 40 meters but 15 meters is a different story all together. With me getting contacts in Russia and Japan on this trip! If you will notice the power levels are lower, this is because the truck, when shut down, has battery voltages around 12.5 VDC and not 13.8 as these are older batteries, well this produces less output wattage since the voltage is lower. Still had plenty to make a ton of contacts with while I was at the park! Of note here, only the FT8 contacts are with the sBitx, all the CW contacts are with the Ten Tec Scout 555 portable radio. I did scan through the 15 meter side band section of the band and heard zero QSOs so that is why I went to CW. There was a station with a mild pileup on CW and so I moved up 5kc or so from them and set up shop there for a while. I was able to get all three west west coast states a Russian, a Canadian, and Massachusetts! Enough about the Ten Tec Scout though, this is about the sBitx…

The sBitx is up and running again and it is all good now. The radio runs flawlessly (other than the SSB audio) and I am happy as a lark now. More to come as they software gets dialed in for better CW operation!

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

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

Cypress Creek Preserve K-7389

Cypress Creek Preserve is a new-to-me POTA park and I think that at this point, I have worked more Florida parks than Georgia parks! That is irony at it’s finest right there!

This is a really neat park as it has ponds with lily pads and hiking trails and all sorts of other stuff right from the outset. Most of the other parks I have been to in this area are not quite so enticing when you arrive with it being more of a parking lot and a simple trail into the under brush more than anything else. It took me a minute to confirm that the parking lot was within the park boundary, but I finally did and setup my radio accordingly.

Once I was parked and started to deploy the antenna, I found this little guy supervising the operation to make sure the antenna was in the proper position to be able to work Europe as well as the west coast. I am really grateful too as his efforts came in handy on this activation!

As you can see in the above photo as to why I wasn’t sure where the park boundary was as there was this huge fence between the parking area beside the road and the park itself, but after checking several maps, I was able to figure out that the parking area was in fact in the boundary.

Once again, to see what I could do at mid day on 15 meters, I decided this would be the only band I setup on.. I ran out the one 20 meter radial that seems to help the 15 meter band and used my 25’ coax as well and the SWR showed up at 1.1:1 which is great in my book so I immediately hop on FT8 to see what is happening while I setup the logbook on HAMRS and get my spot on the POTA site.

Well, it was doing great as I worked something like 6 stations before I had time to put the spot up on the POTA site! This is awesome! I was thinking this might be a day where. I work 50 or more contacts from the way it started…

The antenna system at this point is almost a joke to be honest about it. This radial works on several different bands really well and it is broken speaker wire! I have a spot in the wire where it is literally twisted together so that it is the right length and I am afraid to solder it as when I solder this wire, it breaks next to the solder joint. I have done all sorts of things to try to prevent this too, none of which have worked long term. So I have reserved myself to using it till the SWR readings start to show too much of a mismatch and then I will actually work on it. I use this radial on virtually every outing too, that is part of the comedy of it, the broken radial gets the most use…so is life I guess. Since I was backed up to the fence like you see below, I ran the radial over the fence and was able to lay it out in the grass behind the truck properly.

The activation did hit a few lulls, which was handy as it gave me time to catch up the log in HAMRS so that when I finished the activation I was able to email the log to myself so when I get back I can upload it to the POTA website. As you can see in the log below, FT8 produced a half a dozen DX contacts before I landed my first domestic contact! FT8 is a DX paradise to be honest about it. The weak signal capability of that mode is hard to grasp to be honest. I know this as when I switched to CW I heard nothing but Domestic stations for almost the entire time with the exception of two DX stations that were booming in. This is what I am used to doing to be honest, a sprinkling of DX with almost all domestic contacts.

Here is what is odd about FT8 though, when I went back to work some more while I finished up the logbook, I worked almost nothing other than Americans. It really is the luck of the draw it seems, but you could see on the waterfall that the band had some significant fading at this point and some stations would shift almost 20dB in signal from one cycle to the next, that is pretty drastic and makes me wonder if I had got on the air a little earlier if that would have made more of a difference…

Take a look at the CW portion of the activation and you will see a 10 minute period right in the middle where there is no contacts at all. This isn’t me leaving the station for some reason, I was calling CQ the whole time, there just wasn’t any takers. Then Julia (N1XV) answered me and it took another five full minutes to get another contact! This is unreal in my usual activations …albeit those usually happen on 20 meters and that seems to be the watering hole for POTA CW ops for some reason… Back to this activation, then I work Paul (KJ7DT) and then you can tell the band turned back on as I worked several contacts in a row without stopping as I can work about 1 per minute at the speed I like to use (17WPM to 22 WPM).

By the time I had the logbook caught up, I had worked over 35 QSOs so I wanted to see if I could get to 40 before I went QRT at 21:00 UTC as I had to leave about that time. I was able to get to 41 and go QRT wihtout any replys well before I ran out of time so all is good in the world!

What a day! 15 meters gave me a wonderful activation and I got a bunch of DX as well as cool domestic contacts! What more do you want?

73 - WK4DS

A 2 park…digital rove on New Years Day???

I wanted to activate two parks today so to add some challenge (for me that is) I decided today I would only use FT8 to get the activations. The bands looked good so I had high hopes.

FT8 was alive and well on 17 meters this morning.

The cool thing about the sBitx V3 (I did the software upgrade but have not changed my finals yet) is that you don’t need anything but the radio itself to do FT8. No keyboard or mouse or anything. So I setup at K-2169 and get started with my deployment and decided to start on 17 meters first to see what was going on as far as activity. To say the band was active would be an understatement. The FT8 portion was buried in activity so I looked around and found a spot to setup to transmit and got started. The first few were Americans and then I started getting DX stations! A lot of them too! I even got the DX-pedition to T32TT in the log! To work them on 17 meters and a hamstick with 20 watts, that is not bad in my book. The signal reports reflect it too lol, just look at the logbook in the photo. I think I netted equal numbers of dx stations compared to domestic stations this time out. That is pretty awesome for someone who rarely sees dx in his POTA log at all!

This is the display of the sBitx V3 running FT8. Everything you need and nothing you don’t. Since it is a touch screen radio, all the buttons are on the screen and if you want to dial something up, just touch the function and then turn the multifunction knob to adjust it. Just don’t forget that the knob is set to that function till you choose a new function or you will think you are about to turn the volume up and instead you will change something else… so to prevent problems, I just select the volume once done to lock the function and prevent accidental changes.

I ran out a pretty good radial field today with four radials, two for 20 meters and two for 17 meters. I simply spread them out behind the truck in the grass and checked the SWR with my nanoVNA (which showed about 1.6:1 SWR

This has become a permanent part of my field kit at this point, I literally check my antenna every time I go to the field now.

I have noticed over time that the SWR has slowly crept up as I have used the equipment. What was once 1.175:1 is now 1.6:1 so before I go out again I am going to do repairs to my antenna system. This is one of the reasons I like checking the system before each activation. Data tracking is an ongoing process. I suggest you get one of these little widgets and just keep it with your portable kit if for no other reason than what I have described here.

The spot, in the above photo, has kinda become my defacto POTA spot on days when I don’t have a lot of time to do radio, but I still want to. It is in a good spot, fairly remote from human activity noise (aside from the occasional frisbee golfer or two) and also has good elevation too. It is quite possibly the perfect location for POTA.

Today also saw the use of the keeper pin I made a while back too. This is for times, like now, where I plan to move between parks and simply remove the hamstick from the mount so things don’t break it off, like errant tree limbs on backroads, and keeps the mount secure for travel. I also didn’t bother to remove the radials either but stuck them in the truck bed to be pulled back out when I got to the other park. I disconnected the coax and just rolled it up in the back seat of the truck since it is so long that it drags the ground.

Once I had gotten setup at K-2169 and was going well, I thought about also running over to K-0716 and getting in an activation there too for the first day of the year. It is about an additional 30 minute drive from Cloudland to Chickamauga but I have a favorite spot there too that doesn’t seem to be a problem with the rangers so I packed up enough to drive and headed over there once I had the activation in the bag.

The main road between Ft Oglethorpe and Lafayette Georgia is Highway 27 and when I was a kid, this highway passed right through the military park, I can remember riding through the park and looking at all the monuments and wondering what they really meant… It meant a lot of people died terrible deaths for ideals… I don’t want to wander down that path here, the point was I have a lot of memories of this place from my childhood and it is interesting to see how it has changed. Now there is a bypass road that circumvents the park entirely, you actually have to take, what is now a side road to go through the park. Kinda surreal to me to be honest about it…

Once at the park and in my favorite spot, I pulled all the radials back out and this time, I put the 20 meter ham stick on the mount. I actually figured the SWR would be better on 20 meters and it was…marginally. Take a look at the chart below though to see how deep the FT8 area was with hams calling each other. It was pretty much saturated with signals. This is a level of saturation that I only see on 20 meters too for some reason, the other bands might be busy, but it is nothing like 20 meters for some reason. After watching it for a while, I finally found a spot to setup for transmit and got to work. What is odd now is that I didn’t get near as many DX stations in the log as I did on 17 meters. There were plenty out there with strong signals, but I only worked one DX station from this activation location and band. Just odd to me how that can happen.

Below is a tidbit I wanted to share with you about how I log. I use the HAMRS logbook app for iPhone, while it is connected to the POTA site it pulls all sorts of data from it apparently. Like the ham’s information if it is stored in the HAMDB database and auto populated the fields if it is there. If not, then that station doesn’t show up on the QSO map as there is no GRID info for them in the log, just remember that if you want the map to work right. I just go to QRZ and copy the grid info for the ham that doesn’t have it in HAMRS and then edit the QSO and add the GRID info and now that call will show up on the map. Another cool thing is that it pulls the RBN data for you if you show up and gives you these little green info graphics letting you know you have been spotted, that is cool as I can leave the log open for adding calls and still get the beacon reports, it will even show the ones manually uploaded by hams on the POTA site too…just to let you know.

In the left side of this photo, you can see the cars on the highway that I was talking about. This little pull off is right off the main road which is super convenient as this road passes right through the heart of the park. You can also see the radials in this photo going out and I don’t have them staked down but rather they are held in place with weights so there is no impact from me being there at all. This gets around the “no driving stakes in the ground” rule that a lot of parks have.

All in all, it was a great day of radio and I was able to complete both activations with plenty of time left over. Set some targets occasionally with your activations to give you something to do other than just make contacts if you want to spice up the whole thing. This was not too awful to pull off…it was actually easily doable without much fuss at all for the most part.

Until next time,

73

WK4DS

How well does 17 meters work?

I see a lot of people on 20 meters, but what about 17 meters? I take the sBitx v3 to Cloudland Canyon State Park (K-2169) for a little fun on 17 meters today…

sBitx V3 running FT8 natively on 17 meters.

The WARC (World Amateur Radio Conference) bands are nestled between the typical bands and everyone knows what they are because it is on the license tests. The ones I am referring to, in case you forgot for some reason, are 30 meters, 17 meters and 12 meters.

What the license test doesn’t teach though is that each band has unique characteristics that make it fun to use…at least that is how I see it. Since each of these WARC bands are stuffed between other typical ham bands, they seem to take on the characteristics of the two bands they sit between. Take 30 meters for instance, it will act like 40 meters with NVIS propagation on my hamstick to work hams just a couple hundred miles away and then I will work the west coast on the very next contact as if it were also a 20 meter contact.

Well, the higher the bands get the further they tend to reach more distant stations for me. I don’t have giant towers that have huge Yagi antennas on them for say 40 meters so my results are more of the typical ham who might have a dipole that is technically too low to the ground for textbook operation or a vertical with a couple of radials…you get the idea.

The 17 meter band has the same characteristics as 20 meters as well as 15 meters a lot of the time. For me the higher the band, the better the DX usually. I guess it has to do with the fact that the higher the frequency, the smaller the antenna and with a smaller antenna, the lower it can be to the ground and still have proper performance. Armed with this VERY basic knowledge of antenna theory, I usually expect some cool European stations on 15, 12 and 10 with the occasional DX on 17 meters, but today the sky was alive! Well, it would fade in and out and you can see it in my logbook reports. The signals reports over the time period of the activation go from 599 both ways to dismal 529 and 229 reports within an hour. This has been the norm as of late too, a lot of my activations lately have had events that would be described as cyclic in nature. I would hear a station call and reply to them with a 599 because they were booming in and then when I turn it over to them to reply, they will be a lot weaker and then you can literally hear them fade out while you watch and then fade back in by the time they turn it back over to me. It is really odd to hear that in real time for some reason.

When I got to the spot I wanted to use for the activation, I was the only one there. So I setup in my usual spot and figured I would start on 17 meters to see how things were and if it wasn’t really happening, I could move down to 20 meters and get the activation easily there. I should have known things were going to be good when my first station of the day was VK3AWA!

Now you need to know something about me here. I thought this was a Canadian station since the call started with a “V”. I work so many Canadians that I have become accustomed to hearing the V callsigns and happily add them to the log. It wasn’t till I checked the QSO map that I realized that he was actually in Australia!!! They (it is an Australian club call) must have had a Yagi antenna pointed at me or something, along with a path opening as the signal reports were really good for a 12 watt transmitter running into a ham stick antenna on the back of a pickup truck. This contact was on FT8 and FT8 reads the signal strength in dB with the software to get the most accurate reading possible to send back. So it isn’t quite as subjective as something like CW where a lot of people (me included) will send signal reports based on how the op sounds to them and never reference a meter one time… So for my little radio to get a -8dB report from Australia had to have help from the atmosphere and probably a very good antenna on their end.

FT8 is a relatively new mode for me. I have normally not done anything other than the two original modes of CW and voice. For me to reach out into a new mode is a pretty big deal and this one works really well, which is why I like it. I am also looking to start messing around with PSK 31 some as well as possibly RTTY if I can figure out how to get the little radio to do it. I think PSK 31 will be pretty easy to master, so I will tackle it first.

The above map shows the performance you can normally expect from a band like 17 meters. Notice there is practically no contacts inside of about 600 miles other than two oddities here in Georgia? That is because of the antenna and the ability of 17 meters to have a pretty decent take off angle and also to reflect off the ionosphere easily. This garnered me a ton of contacts in the pacific northwest as well as the Atlantic north east and a scattering around the country to include Utah and southern California. Then there is the EU… I made several contacts with France and Germany today. That has been a little unusual lately for me and my system to be honest so I was stoked to see them in the log.

But this trip did something that I had not done before that I can remember… It netted 7 Canadian QSOs alone, combined with the other DX calls I technically activated today with only the DX contacts! That has to be a personal first.

I started with a DX call and finished with a DX call. How cool is that? It was a great day for radio and I really enjoyed using the sBitx with the new V3 firmware. The radio works so much better than the previous firmware and the FT8 is a breeze in the native radio setup. It you are into smaller radios and smaller companies and the idea of help from a collective of literal geniuses that willingly share their information with you, then this just might be a radio you will like. It is for me, I have had so much fun with it that it is hard to understand how I got along without it before…and the people over at HFSignals dont even know who I am…haha.

Got an activation in right before 2400 UTC with the deer!

It had been a week since I had been able to activate a park…

Even though I had to work till nearly 22:30UTC (5:30 PM local time) in the machine shop, I finally just put a radio in the truck and went to my local park K-2169. I get there just before dark and hurriedly put up the 20 meter ham stick and I ran out the 20 meter radial I have been using lately and also ran out the two 30 meter radials as well as I had planned to hop on 30 later if 20 didn’t do any good.

I get on the air and it is dark enough that I cant easily see the logbook now so I setup my pocket flash light in the truck for a lamp to work by for the duration of the activation. If you look in the above photo, you can see it wedged in the seat on the other side of the center arm rest. By pointing it at the ceiling, the light would bounce back down and be a nice soft light that was easy to use for the activation. This is an old photography trick I learned a long time ago for using lights with people in photos.

I sat in the truck since it was in the 40s at this point as well. I did plan ahead and I ran the heater wide open while I was setting up the antenna so the cab would be good and warm when I shut down the truck engine so I could hear easier and to also eliminate any possible alternator whine or computer RFI that might be coming from the truck electronics.

With the sun setting fast I wondered if 20 meters would hold up long enough to secure the activation. Well, it did hold up just fine and then some. In fact it held up so well that I never changed over to 30 meters. I started on FT8 while I was getting my logbook ready in the HAMRS app on my phone and my spot on the POTA website and such. I normally don’t have much luck if I start on FT8 for some reason so today wasn’t any different. I made one QSO, yeah… one in like ten minutes. So then I moved over to CW and things immediately picked up.  It was awesome as I had a run of about 15 contacts in about that many minutes. I like these kinds of rates where it is manageable and basically as soon as I finish one QSO another calls in to start, sometimes there will be a small “pileup” of sorts where two or three might call at once but that is usually all.

So with the activation officially secured I moved back over to FT8. I really wanted to work this mode some to see how it would perform with the new software compare to the version 2 software. This time things went better as it has happened the last few activations too. I am going to go out on a limb here and say that it is probably because I am spotted on the POTA site at this point and most of the QSOs are POTA contacts instead of just people answering my CQ calls. As for the version 3 software, I love the new interface and functionality too. It works a lot better than the version 2 software did and it is easier to use as well. I also really like the native interface over the web GUI version. The GTK (I think this is what he calls it) seems to run smoother than the web version for me. It is also easier to adjust controls too as you simply touch them and the multi-function knob now controls that function. The auto logging function is still a little buggy in that it doesn’t seem to auto-log each QSO, but it isn’t a problem for me as I log them manually anyway too. I figure this will get solved in an update at some point so I dont worry about it for now.

Once I finished the activation, I go out of the truck and find all sorts of stuff that I don’t get to see if I leave before dark. This is the frisbee golf course at the park and I am in a remote parking lot that serves this course, well the park has an abundance of deer in it and apparently they were about to have a meeting or something because they were all around me when I lit up the tree line with my flash light! I also saw that the moon was really interesting so I grabbed a photo of that while I was at it to share with all of you as well. Note that this is done on my iPhone too, this thing has some sort of lowlight mode and does this long exposure trick to get good photos in poor light. I was impressed. You can see me hamstick in the corner of the photo too…haha.

So, with 30 QSOs in the log, I called it quits before the UTC day rolled over and packed it all up and went home. Thanks for following along and I look forward to sharing the next one!

73

WK4DS

2 x POTA Activations plus a new to me mode! FT8 has entered the chat!

I have been busy lately so I thought I would combine the AARs for two activations into one report. These went very fast, well, one of them did. the other did last a coupe of hours and involved me doing something very new for me…FT8…just not with the Penntek TR35. It was used to make CW contacts at the first activation.

The first park I went to was my hometown park K-2169 Cloudland Canyon State Park. This is my go to park when I don’t have a lot of time. I also can go to the Sittons Gulch parking area which is much closer than the top of the mountain by a solid 15 minutes of driving. Well, this is where I went and during the week, I can also get to choose my parking space most of the time too. Today proved a little tough but it worked out. When I got to the park there were a few cars already there and they were literally in all the places I like to setup, save one… So luckily for me there was a space in a corner like I prefer to use as it gives me room to deploy my counterpoise wires and not have to worry about people tripping over them.

I also only deployed a single counterpoise element today as well. I was curious if it would heavily affect my ability to make contacts with only a single radial, but it didn’t seem to matter much on this day. Due to my spot, I was able to run it straight away from the truck too for what that is worth. Seems that if I don’t use a radial at all, the hamstick will use the coax and the truck body for the counter poise and I will have about a 1.8:1 SWR on the nanoVNA, but if I simply add once tuned radial, it drops to 1.2:1 and if I add two it is pretty much 1:1 SWR. This is why I always deploy at least one if there is time at all, it helps with my transmission pretty dramatically. I found this chart online and used it as a reference to see what would be the results of better antenna SWR and as you can see, at 1.8:1 you lose almost 10% of your energy and at 1.2:1 you only lose about 1%. This is why I don’t worry about deploying both radials if I am in a time crunch. I also know that there are a lot of other things at play here like radiation pattern and take off angle, but it is pretty consistent since it is a ham stick every time and I cant easily change that.

Once setup I immediately jump on 20 meters to get things going today and it did not disappoint! 20 meters was alive and well on this day with a lot of activity.

Today’s weapon of choice is the Penntek TR35 Amateur Transceiver. I bought this radio last year for this reason alone and it took me a while to get around to using it as I was trying to get my IC-705 up and running at the time. I finally came around to the concept that the 705 just wasn’t for me and stopped using it. Sometimes a radio, even a wonderful machine like the 705, just isn’t the radio you want to use, so I sold it back in August. I kept this radio though as I really love the whole radio, literally the whole thing is as close to a perfect CW rig as I could get. It has every function you need on the surface that you could want and nothing you don’t need. The built in filters are really well done and it can even listen to SSB if you are into that sort of thing. The compact size also makes for another reason I like this machine, it is destined to be my new travel radio replacing the venerable Elecraft K1 that I also sold last August due to lack of use. I do want to add an antenna tuner at some point to this kit so I can use random wire antennas, but for now it has a tuned antenna in the kit.

This is the kit when setup. The Penntek TR35, the N6ARA Tinykey, a set of simple headphones (with an adapter to make it play out of both ears) and a 10 cell AA battery pack. I chose a 10 cell pack as it will give me almost 13 volts when the batteries are charged and I can use alkaline cells in a pinch by bypassing two cells with a couple of dummy cells I made in the machine shop. The kit also includes several pens, a pencil (since they don’t dry out), a Field Notes notebook, a couple of lengths of coax, one of which has a ferrite bead common mode choke built into it, a 40M EFHW antenna with an additional radial for it and a throwline with a weight, everything you could need to get the little machine on the air.

Here is another thing I like about using my truck for POTA, I can use the bedcover for a table and just spread everything out on top of it like you see in this picture. If I can operate outside I will always choose that option, but sometimes, the weather or time just prohibit that.

I had a good run with the little Penntek TR35 as you can see in the log. So if you wonder how well things can go, this is a 5 watt radio into a hamstick on my truck. It is one of the worst possible arrangements you can possibly come up with and I still ended up with almost two pages of contacts. Now if the bands are trash, then all bets are off, but you really don’t need a ton of power to do a POTA activation and have a good time. On to…

North Chickamauga Creek WMA K-3958

The next outing was in Tennessee at the North Chickamauga Creek WMA in Soddy Daisy TN. This little park has not seen a ton of activations and to prove that, just go to this parks page on the site and look at who (with only two activations mind you) in the top activator and also who holds the highest QSO count as of this writing. Yeah, it is me. There have been some people activate this park, but it just doesn’t get the attendance of places like The Great Smokey Mountains or even Cloudland Canyon State Park. I don’t understand why either, it has easy access and is pretty close to town. Maybe after I write about it and give it some notoriety it will see some more attendance…who knows?

I was here on a Friday during the mid day hours, so the park was pretty much abandoned except for me and a couple with their dog in the river bottom. I setup in a spot where I had room to deploy a radial and got the sBitx v2 out this time as it has a mode built in that the Penntek TR35 does not…well actually it has a bunch of modes that the Penntek doesn’t have, but this radio is special in that it will do FT8 natively in the radio. Yeah, no computer, no sound card, no setting up complicated software, no figuring out how to get the computer to talk to the radio and vice versa. You just choose FT8 from the mode list, dial up the frequency, set a few things like your call sign and grid locator and hit Call CQ. Now, the radio is a beta version of sorts and it has a few bugs to work out, one of them is currently in the FT8 section too, as long as I am calling CQ and a QSO ensues, the whole thing works like clockwork, but if I answer another operator’s CQ it has a glitch and wont sequence correctly. So I can use it for now, but only if I call CQ. Even so, it still works and I made almost a dozen contacts on this day with FT8, so I am happy about being able to use another mode on activations.

Here you can see a QSO has just finished with WD5BFH and the radio even logged it for me! Oh yeah, it even has a logging program running in the background to log your QSOs as well. I really like this radio.

Here we have the antenna layout for today, the single radial was really close to 45 degrees due to the slope behind the truck. That made the SWR even better and I was stoked to get on the air and see what I could find out there in radioland.

I am also testing the reserve capacity of this 8aH battery I bought last year off of Amazon, I keep turning the power up higher and higher to see if the battery can handle it and today saw me using 30 watts of power for almost two hours! I shut down the activation because of time constraints and not because of the battery so it works great for my needs.

Once again I was able to setup on the truck bed cover, and I am acutely aware that I need an easier logging process. Hand written logs are nice, but they are slow to transcribe. I am thinking that I too can come into the 21st century and use a computer to do my logging…I know, I know. I have really railed on battery powered devices, but at some point I guess I just need to bite the bullet and get a computer of some sort for logging. I am thinking of using a Linux based OS for this as these seem to be more reliable and do not update and crash all your stuff… windows, I am looking at you.

This display below is not how it looks when booted up for the sBitx V2 in the native configuration. I have scrolled it down to be able to see the top QSO in the logbook so I can confirm the QSO did in fact get logged when running FT8. The photo underneath this one is what the screen looks like when opened initially. The screen has more information than can be displayed normally so since it is a web browser layout, you simple scroll down to see the other intel. Things like the on-screen keyboard, the logbook and the macros (message memories) are what you find when you scrll down. But the way I have it here is an efficient way to run this mode for me as you can see everything you need on one screen. Sorry for the reflections, it was tough getting this frame outdoors.

This is the native layout at startup.

You can see the time stamps for the FT8 contacts are pretty spread out. This is a function of my operating skill level being low and the lack of “responding to other calls” being buggy with this mode. I know this because the band was on fire that day.

All in all I had a great couple of outings for POTA and radio in general. I hope you enjoyed these after action reports and look forward to seeing you again soon!

73

WK4DS

A quickie activation at Cloudland Canyon

Today I only had a short time and I wanted to get on the air so I loaded up the sBitx v2 and headed on over after work.

So I get to the Sitton’s Gulch parking area at the bottom of the mountain so I can save another 15 minutes of diriving time. I am in luck too as the parking lot was really empty to a and it allowed me to choose my favorite spot.

To get things on the air faster, I also used my hamstick for 20 meters and just ran out one counterpoise radial. Another thing that I realized today is that I need to work on my antenna parts as the radial was broken and the sta-kon also broke off where I connect it to the antenna mount… there is always something to do it seems. Luckily I made the mount to where I could also insert just the end of the wire and it would still work. This arrangment provided me with a 1.2:1 SWR as shown on the sBitx radio when I would transmit.

I also found that the wire was also broken in the middle as well. So I simply twisted it back together and just used it. It seemed to work just fine, well…it got the job done... I know there was something probably amiss with the current flow, but it got me on the air. We all know it works better when you have a continuous piece of wire, but if you don’t have one, you use what you have. In hindsight I should have just gotten the other radial out for it as I have two just alike, but you forget simple things like that when you are stressed out with a short timetable to work with.

Another noteworthy thing that happened today was that I rolled down the back window for the first time is about 3 or 4 years. You see this window stopped working several years ago and I knew what was wrong. The wiring passage from the truck to the door where the wire bends will eventually break these wires, it is an absolute that it will happen. Shortly later the other back door also failed in the same exact way (It is still broken as of this writing). Well, I finally got off my lazy rear end and ripped the truck apart last weekend and actually rebuilt the wiring harness through the flex conduit as you can see in the photos below. I plan to do the other door soon and I will actually video that process and plan to put it on my YouTube channel. It allows me to roll the window up and down AND the power door locks works in this door again!!! WOOHOO!!! You just don’t understand how convenient having this feature is until you don’t have it. Every single conductor was broken too, literally not a single wire was intact…lol.

Testing the connections before routing the wires back through the door and into the chassis post.

That was then and this is now, and now it his high flex silicone wire in the high stress area of the conduit so it should last the rest of the life of the truck at this point. Now to do the other door this coming Saturday morning if all goes according to plan.

The radio of choice today was the sBitx V2 that I ordered back in August. I have had this radio for a little while now and I really like it, it does have a few quirks I would like to iron out, but for the most part the little radio works really well for me. I have done a couple of mods to it that I felt needed to be done pretty soon as it would get crazy hot on a POTA activation. (There is a blog post where I used it a time or two in this blog if your interested that I wrote about before this post.) The main one was that I added a fan to the power amplifier heat sink that is temperature controlled so it cycles on when the heat sink gets to about 115 degrees. I will spell that out in a blog post incase you want to add something like this to your radio. You can put the fan control circuit on any radio and not just the sBitx. I thought it was a brilliant idea to monitor the temp and the fan works so well that it will cycle on for about 1 minute or maybe two and then cycle back off as it has cooled it down low enough to drop out my monitor circuit.

Another huge benefit to using a radio that is basically a computer with an RF deck attached is that you can do things with it that you can only dream of on other radios. The photo above is a perfect example of what I am talking about. This is the bank of TWELVE message memories that I use when operating POTA as an activator or a hunter. To be honest though, F3 thru F8 don’t get used at all, I thought it would work for me but my process flow while activating just doesn’t allow for it at this time so I still send this part of the exchange manually. But the CQ sections and sometimes the others do see a good bit of use. I use the CLOSE memory to give me time to log the contact in my logbook during pile ups. When the pile up comes, I don’t have time to send some of the exchanges and also write so I use this to be able to write down the information for the exchange at times. If things are slow enough, I will usually just send everything though as I like to send CW, it is just nice to have things like this to help.

Another thing you don’t see in the photo that is available, is that you are not limited to 12 memories, but you can open the little box beside F12 and choose another bank of 12 from another menu item, here is the cool part, you can have as many pages of 12 memories as you want, the only limit is your memory on the Pi. It is literally a script you fill out and save in a folder on the Raspberry Pi. That is just plain awesome. Another thing that is nice is that mine has the Real Time Clock module and if you will notice it knows what the time is so I don’t have to try to use my phone to tell the time for the contact info. If I were to work on it a little harder, I could even do my logging on the radio as it has logging software built in and can be configured to work with the mode you are using. I just like to log on a paper notebook myself and have not bothered to learn it. That is what the section right about the macros is for…

All in all it was a great outing albeit very short. I did have to get back home pretty quick so after I cleared the small but rather exciting pileup, I called CQ a few times and when I got no answers I called QRT with 20 QSOs in the log. Two of those QSOs were DX too! One was Canada and the other was Spain of all places! The Spanish station was booming in as well, very loud to my hamstick. I don’t know if he sent back a 599 because I was also just as loud or if he thought I was simply sending a contest style exchange, but it was nice to work him none the less and I did it with 25 watts too, for a 30 minute activation, that ain’t bad in my book.

All in all it was a great time to get out and make some contacts and to use the sBitx out in the field too. (Which is what I bought it for to start with.) So more to come from this wonderful little radio and my park adventures! Until next time, 73 and get your radio out!

WK4DS

Activating K-2169 and some notes about radials and SWR that I saw today...

Ok. Radials

Today saw the use of the sBitx v2 again as I wanted to work some FT8 as well as CW. I setup at the frisbee golf parking lot on top of the hill and decide to measure the SWR plot as well as check to see the Smith plot as well of the ham stick antenna and add counter poise wires till it quit making it better. I did this because I received a comment from a ham asking about any info I might have onthis subject since he is wanting to pick up a ham stick and mess around with it.

In the above photo, we have the ham stick on the receiver hitch mount that elevates the radiator to about 6’ to the bottom of the antenna. The antenna is only wired to the cab of the truck with a 15’ piece of coax and it terminates into the nanoVNA through a common mode choke. At this point I had not turned on the 2nd trace to see the smith chart…sorry about that. In all fairness, this could be used on the air with practically no worries, I would probably turn the power down to prevent heating of the finals from the SWR, but that is me being cautious. This is completely usable to be honest.

In the above image I have added a single, approximately 15’, radial and ran it straight out away from the back of the truck. This is completely usable and I have had great activations with just this one counter poise wire. Dropping from 1.574:1 down to 1.226:1 doesn’t sound like much but it really is when you are working towards a resonant antenna. Also notice how the null point is climbing in frequency as the radial field grows under the antenna.

In this photo we see the SWR plot has gotten spectacular! I added the tuned radials for the 17m antenna to the one radial I already had installed so now I am using three radials with the antenna and look at that plot. I arranged them 90 degrees apart as this also matters. The more this angle changes the more the SWR changes too. Sometimes for the better, sometimes for the worse. Notice how it raised the frequency of resonance as I added counter poise wires to the system and it lowered the SWR to 1.028:1 as well as made the antenna slightly inductive instead of capacitive. This shows that the radials are more than simply a ground path but rather part of the tuned circuit that matches the radios transmit frequency and improved that whole system. If you have the space and time, I highly recommend adding counterpoise wires to your system and measuring it with something like a nanoVNA.

Another thing I learned is that I get best performance when the wires are pulled snug as you see in the photo above. I think this might have something to do with when I originally set it all up, I tuned them with them under tension like this which makes the wires the longest and also this changes the capacitance and inductance of the radial from just being thrown on the ground. As a matter of fact, it was when I tensioned the radial shown above that the SWR plot bottomed out like you see. It was the last one to be tightened and it made a huge difference.

By parking in this location I am able to get the radial at almost a 45 degree angle to the antenna or very near it. This matters as it is the point in the radiation pattern where to get a 50 ohm impedance match to the coax feeding it. There is tons of information out there on how to adjust the impedance of the antenna by adjust the angle of the radials…it is like some sort of dark magic to be honest.

I got on the air and started on 15 meters as it looked promising today with the noise floor being good and FT8 being quite active. As you can see though it took me quite some time to get just 6 QSOs in the log. After I worked N7ZLD I went over 20 minutes without a single call, that was when I decided to jump on FT8 to see if I could get a few in the log like that. It was slow going, but that it the fault of the radio software more than band conditions so I was happy to get 4 FT8 QSOs in the log, securing the activation only on 15 meters for a change!

After playing on 15 meters for a while I decided to see what 20 meters sounded like (I didn’t even check the antenna, I just plugged it in and got on with the activation). I quickly found myself in a small pileup working through several call and the calls kept coming in for a good while one after the other and sometimes two at once. This is the pace I really like as I don’t feel like I am missing anyone that wants the park I am at. After a great run on 20 meters CW I once again switched over to FT8 to see if I could get a few there. It took me a while to get someone on the hook, but I did work 5 more and the last one was W0NKA!!! That is (W -zero- NKA) and he is awesome, go look him up on QRZ and see about the special event he is having in December where you can get the golden ticket!

All in all it was a wonderful activation and I hope you enjoyed following along today, until next time I hope to hear you on the air.

72

WK4DS