Finally got my sBitx V2 radio…so I went to a park!!!

Quick synopsis is I like it. Read on to see why.

When you see this radio, you think it is like one of the big name machines. It is not. It is actually so much more because of the nature of the project that it comes from.

The HF Signals sBitx V2 is an evolution in their radio designs and brings so much to the table that is cant be described in one blog post…well maybe…I can write as much as I want in one post…lol.

The TR-35’s magic is the lack of menus.

The first thing you notice it the lack of buttons or switches like my Penntek TR-35 has on it in the photo above. There are simply two knobs and a display and that is all you are greeted with at first glance.

Well this is a kind of sleight of hand trick as the display is actually a touch screen and almost all of the controls are driven from this display. In fact, what appears to be at AF Gain (volume) knob, is actually like the multi-function knob on my Ten Tec Omni 7 being selectable for an array of things it can control.

Both knobs are also push buttons and the smaller one defaults to volume control if pressed, but the larger (VFO) knob doesnt appear to do anything when pressed, I can not find anything in the literature describing it so it is there for tinkerers from what I gather. You see, this is an open source SDR, this menas you can download the source code and if you are savvy with coding, you can add features or modify how the radio works to suit you. This is the point of the whole project to be quite honest. This radio does work, but it is not as polished as a big brand machine as it is intended for the owner to go inside and play with things, like add circuits or modify existing ones or even write new features to add to the radio outright. You can literally download the schematic and the actual source code from their GitHub… What ever you want to do, this radio is fully “unlocked” so that you can do it.

Enough about the radio in general, how did it do on the first outing to a POTA park? Well, it did really well, I did power it from the truck battery which means I had to setup in the truck somewhere so the power cable would reach the connection I have in the truck. (I finally added a power pole cable inside the truck cable that is fed directly from the batteries so losses are a minimum.

Back to what I was saying, I got to K-2169 and setup in the truck so I have somewhere to sit this time as I planned to stay a while today and didn’t want to have to stand up the whole time. It took me a few minutes to get it all organized, but once I did, everything fit quite well. I wanted to use my N3ZN key, but to be honest, this arrangement literally made it impossible, so I defaulted to the little travel key I have used so much over the last year. I didn’t have a table top that was convenient to setup the other key on and I even tried to sit the N3ZN key on my clipboard, but it was just too difficult and I kept running into problems trying to use it. Hence you see the Gemini cw paddle in my hand for this activation.

Once I settled on the key and radio, I chose 15 meters to get on the air, the band was wide open and even the propagation report said it would do well… Well, FT8 was rocking pretty strong (I tend to use these guys for my beacon report on a band), so I move down into the CW area and start calling CQ…and I call and I call…and nothing. Seems either no one was on the band or they simply could not hear me. It did appear that the band was fading in and out pretty bad though as the RBN would give me a great report one minute and then it would go 3 minutes without a single update. So after what seemed like an eternity on 15 meters, calling CQ with no answers I caved and went down to 17 meters to see what I can scare up.

The hamstick collection at this point. 15 (Green), 17 (Brown), 20 (Yellow), 30 (Blue) & 40 meters (Red) are all represented here (well, 30 meters was on the truck when I took this photo)

So since I had not edited the memories in the sBitx V2 yet for my use, I planned to use the PICO Keyer I picked up a while back, well it worked somewhat, I think it had trouble keying the radio because the radio is looking for contact closure and not a semiconductor so it would work, but it was introducing errors into the code pretty bad. I finally threw in the towel and just used the key the whole time and ran with it. This turned out to work really well though and I really didn’t mind it after all. Once I got home I built a complete set of memories for the keyer complete with all sorts of messages. You get as many memories as you want, they are in sets of twelve, I tested this by copying the CW1 memory and renaming it then I edited the messages and saved it, rebooted the radio (just as a precaution) and the new set of messages were right there in the drop down menu! They are really simple to edit, but you need a keyboard to do it. I didn’t take one with me on this trip hence I didn’t bother with trying till I got back home. If there is demand for it, I will detail how I added a memory and show how to edit the messages and the message names as well.

So I ended up using almost 4 Amp Hours of energy on this activation. Not bad for over 50 contacts in the log. I am happy with that! When I am going to be at the park for a while, I will get all the antennas out and sort them by band like you see below. Well, they are not sorted at this point, but imagine that they are for the story. Then I can change bands quickly and easily as I will lay them near the mount for the truck. The 2” PVC pipe is maxed out too. I don’t think I can get another antenna in it at this point. If you plan to run hamsticks, I recommend that you get some sort of tube to store them in to protect them. They are not very durable in construction so it would be best to try to store them in a way that will make them last.

You see, I know the radio is transmitting as I have been using it at home for the past week or so before taking it to the field. So I get down to 17 meters, find a clear frequency and start calling CQ here. Well things pick up for me here as I get a few answers so I know the radio is in fact working as it should and I didnt do something to it while I had it taken apart… More on that later when I talk about the mods I did to this radio right out of the box.

So after messing around on 17 for a few minutes I hit a dead spot, so I figure it is a good time to QSY down to 20 meters and see what I can find down there. Well, I found all the ham radio ops in the United States and some from across the Atlantic too! I proceed to make over FOURTY contacts in an almost continuous stream in about as many minutes! I was busy! The radio was working great too. At this point, I clear all the callers and decide to try the lower bands for a minute and see what I can do there.

So I hop on 40 meters first as this antenna has consistently been on the upper edge of SWR for my operating preferences, and the sBitx agreed with it showing about 2.1:1 while I was there. Also of note is that the radio self adjusts the output power based on band and SWR from what I can tell. I was running about 20 or so watts on 20 meters and wihtout changing the power setting at all, jumping on 40 meters netted me 9 watts output into the 2.1:1 SWR where on 20 meters I think the SWR was closer to 1.2:1… So I turned up the drive some in an attempt to get the power out consistent across the whole activation. I didnt get it past 15 watts if I remember right… But it was enough to make a few contacts and get some in the log from more local hams as the 20 meter band hops right over the closer states.

Then I finally moved up to 30 meters to see what it could do as well since that was the only antenna I had not tried yet. Well, 30 meters also did not let me down…like 15 meters did… haha. I got it on the band with good SWR and output power and easily made several QSOs on that band to finish up the HF portion of this activation.

The next part is just for fun, but I also recently got a new HT (Handy Talky) radio and was playing with it while out on this day. So I called into the KG4WBI/R 1.25m repeater to see if Roger was monitoring and he was. So then I asked him to switch his radio to VFO and simplex so we could make a 1.25m FM UHF contact. 5 watts was more than enough to make the trip the roughly 3 or so miles it was to his house from my location! So I netted 54 contacts on this day on 5 bands and two modes. I had a great activation and the sBitx pulled quite a long shift on it’s first outing.

Now to discuss some issues I found with the new radio that I am going to look into solving or upgrading. The first one is actually really easy, it needs a fan… or two. The heat sink got SO hot in the two hours I was in the field operating at about 20 to 25 watts. REALLY hot, the whole radio was hot actually and I think this is what made it start doing the next issue..

This is something I noticed after a while, when the radio is getting really warm, it starts to “stutter” in the refresh rate of the screen. I am thinking this is due to thermal throttling of the Raspberry Pi processor in an attempt to prevent sudden death from overheating. I confirmed this was not due to ram overflow by swapping the Pi out with a second one I own that has 8GB of onboard ram and it did it too with minimal use “on the air” back in the shack at home. So my solution is two fold, one is to install a fan on the main heatsink for the power amplifier in the RF deck and a second fan pulling air through the radio chassis where the Pi is located in an attempt to cool the processor as well. I know this will increase current draw from the battery, but I am not concerned with this as my activations normally don’t run over two hours at a time and this limits amp hour usage to usually no more than 3 or 4 amp hours, which even my smaller battery can handle at this time. If adding the fans runs the draw up to 5 amp hours or even 10 in an activation, then I will just take a bigger battery since this is not a backpacking radio in my book. Also, it did work at 25 watts down to 15 watts, depending on band and SWR, for the whole activation. If I were to just turn the power down to 5 watts, it probably wouldn’t get warm enough to matter on the power amplifier considering the size of the heat sink on it. This means I will probably install a small toggle switch to manually cut the power to the fans should I want to run it at true QRP levels in the field. I also plan to wire the fans through a circuit that will automatically turn them on and off as needed to prevent them from just drinking the battery dry when they are not needed. This involves a small temperature sensitive resistor called a thermistor in a voltage divider and a transistor to flow current to the fan. This way if the radio doesn’t get very hot, it wont come on at all. I think I did the math on this device and it will bias the transistor base at about 105F degrees, which is about right for it to protect the electronics. The processor cooling fan could be done the same way (and probably will) but I don’t want this fan to be very large so I am searching for a small 12 VDC fan for this application and also I want to see if I have room to install the processor heatsink, which is not currently installed. This alone will help tremendously, but with long activations the heat will eventually soak the heatsink and we will be right back to square one. This is why I want to add forced air flow to the system…

Even with all the heat buildup, the radio trucked right along and I put over 50 contacts in the log on the first outing! I even got some from overseas in the log!!! It is always good to get some DX in the logbook. I really liked this radio for a station that will be near the truck. The reason for this is that it is fairly large and heavy compared to my other radios, well maybe the Argonaut 5 is similar in weight. This is one of the reasons the Argonaut 5 doesn’t go on activations that stray far from the vehicle too. That guy is heavy, and it is a fairly fragile radio like the sBitx V2. So who knows what I will end up using it for, but for now, it will be one of my POTA radios.

All that aside, the radio works really well for the most part and over time this will be a wonderful little rig to run on activaitons. I plan to get it going on digital modes as well so I can work contacts on FT8, PSK31 and RTTY as well since it does all those modes natively and without the need for an external computer. This was one of the main reasons for getting this radio, I really didn’t want to have to bring an additional computer to the field to do digital modes… Anyway, with all that said, I packed up and on the way out found a few deer wandering around the area and I was able to get a photo of one of them. That was just icing on the cake for a day with so much activity and fun and getting to use my new radio. So until next week, get your radio out and go make a contact with it!

A couple of quick activations testing the antennas

The past couple of days have been busy and there was still time for a couple of quick activations along the way.

First stop is the Estelle Trailhead on Crockford Pigeon Mtn WMA (K-3742) over in LaFayette GA while coming home from visiting with my mom. This is actually a new park for me even though it is only 15 miles from home by road… I dont know why, but I have never activated it for some reason. The Estelle parking area is fully within the WMA boundary so it was a simple matter to pull in, get parked out of the road and setup a radio in the shade for a little while. Today saw the Ten Tec Argonaut 5 again as this radio was the one in the truck at the time. It is also one of my favorite HF radios at this point. It only lacks two things to be the perfect radio, an SWR meter and an internal antenna tuner…but I digress.

I said that I setup in the shade, but there really wasn’t much to start with…lol. I did get lucky and a nice cloud moved in after a few minutes and helped keep things cool. I don’t like to let my radios just sit and cook in the sun if I can help it and will go to fairly great lengths to prevent them from getting hot. This is what you see here. The shade was just wide enough to protect most of the radio from direct sun so it didn’t get very hot before the clouds moved in. On top of that the tool bag is shading my battery in this photo too, I didn’t want it to get too hot either…haha.

I started on 15 meters today as I finally have a 15 meter capable radio and antenna too! Well the RBN showed 29dB for me! That is crazy good for someone with 15 watts under their belt into “7” land. But try as I may, there just wasnt that many hunters on 15 meters for some reason. I did get 3 QSOs in the log while on 15 meters so all was not lost. Then I moved down to 17 meters and did quite well there, picking up several more contacts. Then I finished out the activation on 20 meters which is my backup if I need to get my 10 for the activation. 20 never seems to let me down either as I can almost garuntee at least a few contacts there.

So after getting the activation, I wanted to experiment with the antenna system and see how it would work on the drive home. Turns out the 20 meter hamstick without radials has worse SWR than with them, going from 1.15:1 up to 1.7:1. Who would have guessed? LOL. This is not a real problem though as this is still well below what I consider useable SWR. As long as I can stay below 2.5:1 I will operate. That is the upper limit though and I will work on the antenna a good bit to get it down but if nothing helps and I have 2.5:1 SWR, I will try it. The radios can handle anything below 3:1 so I set my personal threshold below that… I know some people wont use their gear if isn’t almost perfectly 1:1, but I have come to realize that it isn’t so important and the signal reports speak for themselves.

On the drive home, I start hearing this REALLY strong signal booming in to the Argonaut 5. The above photo shows what the signal level coming into the radio was 20 over S9, and remember that the Argonaut 5 has a S meter that doesn’t like to give out good signal reports. So I start working on head copy on the drive and finally get that it is W1AW/0 in Colorado and he (or she) is working as a POTA park! So I do what any sane POTA hunter would do, I pull over at the New Salem Firehall and work them mobile! WK4DS/M got into their log!!! WooHoo!!! So at the bottom of the logbook page you will see where I logged the hunter contacts on this trip since I was not at a park when I made these contacts.

New Salem Firehall parking lot was empty and worked great for getting my hunter contact on the drive home.

As a side note, I finally made the hitch pin (shown below) for my antenna mount so I can use it for the rover program without having to pull it off the truck and stow it between parks. I am working on reducing the setup and breakdown time at each park as I am going to attempt a 10 park rove and this will take planning to make it happen. Things like this can add up on the rove to make it take too long since the drive time from one park to the next will be the biggest time eater of the day. So if I can find simple little things that I can do on each stop to save time, I can make the most of the activation.

I made the main pin that holds the mount, but I simply bought the little pin to lock it in place. Sometimes it is smarter to buy a part rather than spend the time to make it. The main pin was easy enough to make from scrap shafting material. but to make the keeper pin would have taken more than the 3$ it cost in time so I opted to simply buy it instead. To be honest, it would have probably been smarter to buy the main pin too, but I had a scrap piece of round and time available on the lathe so I just carved one out right quick rather than drive to the store to buy one. Another plus is that I could make it like I wanted which included adding the handle to the main side so it is easier to pull when breaking down the system. On top of the pin making, I also opted to add an extra set of holes to the antenna mount so that the pin can be left in for simple POTA activation days where I dont have to pull the pin to simply setup for a single park. This allows me to just stick the mount in the hitch and use it like I have been and take it down when done so I can stow it inside the truck bed when not in use.

The next park I went to a couple of days later is the Chickamauga National Military Park. K-0716. This park lies in two states, so today I opted to activate the Tennessee side of the park. This location is easy to access as it is literally on the side of the road. This is why I like this location and hate it at the same time. The location is called Eagles Nest and is part of the military park completely within the park boundary.

K-0716 presents me with a quandary. This “shack” position makes for a comfortable operating position but the road noise is really bad due to the proximity to the road… I have used headphones here before and that seems like the correct thing to do if I operate here much more. I am going to go ahead and get my repeat offender for activating this park. I am already half way to this award anyway so why not? Ha Ha… Another thing that surprises me is that there are some fairly large trucks to travel up this narrow and winding road to the top of the mountain. Like large d4livery trucks kind of large, I guess it is normal, but it just kind of caught me off guard to see such large trucks going by while I was there.

The radial situation is unique here too, since it is on the shoulder of the road, I have to put both radials on the same side of the truck. Whenever I do this, I always get out the nanoVNA to see what this has done to the SWR plot. As usual, it did affect it but not by much. I was surprised to see that on 15 meters it needed both radials to get a decent SWR before I was happy. So I get it setup, spot myself, start a log in HAMRS and start calling CQ. I finally net a couple of contacts on 15 meters, but there are not many hunters even though the band was open. It did have some fading, but it was fairly strong anyway and could easily support use, but people were not there. So I moved down to 17 meters. Once on 17 meters the RBN (Reverse Beacon Network) picked me up and showed the strongest signal report I have ever seen for one of my activations. 42dB is insane! I have never seen that and this was with 15 watts no less. So people MUST be on this band, right? Well no, it seems that all the people on HF were down on 20 meters having a grand old time without the few of us up on 17 meters. I added 4 more QSOs to the log with one being KJ7DT who followed me down the bands working me on all three on this day. To me this is awesome as it shows the propagation for all three bands was really good as he is in Idaho which is almost 1800 miles from me.

So I finally decide to join in on the fun on 20 meters and QSY down with what seemed like the rest of planet earth and secured the activation in short order. Getting Paul - KJ7DT a third time on this day and Keith WI0S twice! Both of these calls have appeared in my log on numerous occasions. These are some very prolific hunters and I just want to thank them for being there to hunt like they do. They are what make activating parks fun. With 13 calls in the log I officially had the activation so I packed up as it was getting close to lunch and the road noise made it very hard to hear as well and headed into Chattanooga to go have lunch with the girls.

The clip board has made a huge difference in operating ease for me. I can now not worry about the wind turning the pages and it gives me a hard surface to work from no matter where I am. This alone helps a ton. As seen here, I am able to lay the keyer and the key on it as well as log. If you still paper log this is a very handy addition to the POTA kit in my book. Yes, I still paper log. I have had too many computers where they crash unexpectant and you have to reboot the machine and wait for it to get back up and running to trust it with my only log of an activation. The paper notebook gives me a durable backup to my phone logbook that I run at the same time.

Side note about how I log… I will run HAMRS in parallel to my paper logs and if the activation is going kinda slow, I can log both at once and keep the electronic log caught up in real time. This is a recent thing brought on by me wanting to not have to set aside time at home just to transcribe the log so I can submit it online. I found that a lot of my activations are slow enough to permit time to log the QSOs while I work the activation and not have to do it at home. So if things speed up and I cant log both the paper and electronic, then I always default to paper and the battery never goes dead in paper logs nor does the app crash… Then when things slow down, I will let the keyer send CQs and I will catch up the electronic log while I am calling so I don’t waste that time just sitting there waiting on an answer. This works really well and I can normally email the log from the park before I leave so when I get home I can simply upload them to the POTA site since it wont let me upload from my phone yet…

Here is something else that a lot of people that don’t do field ops have no idea about. A carrier with a bunch of backup equipment is a must. Everything in this bag has been used on an activation in the last few months in one way or the other. Notice there is power cords and spare coax and three pens are visible on the side, this is something that you quickly learn, things break, pens dry out, you run out of paper, all of this is things you have to prepare for before going to the park and the only way you learn this is from doing it. I can preach to the ends of time but until you have to end your activation because your coax connector came off or the center conductor broke on the coax or your antenna mount breaks, you wont prepare for it as a contingency. That is just how it is…Another really handy tool to have is a Leatherman multitool of some kind, brand isn’t important, what matters is that you have one, I don’t know how many times I have used mine to save the activation some how. Totally worth the price of admission in my book.

QSO maps are awesome, I have KJ7DT in the log on all three bands today so his one pin is actually three. Just like I have WI0S in the log twice so his pin represents two contacts. This is neat to see though as you get a visual idea of what the bands were like on this day. If I studied space weather more then I would be able to corelate the data so that it would be more meaningful, but like this it really doesn’t tell much other than skip distance for the bands I used. That is about it but it is still fun to look at them nonetheless.

So this is what it looks like to activate two parks on two different days and how the setups vary for each one based on the conditions for each location. Next time I will carry headphones for the one by the road so I can hear better. Till then, get your radio out and make some contacts with it!!!!

Component failure sucks…

When things dont go right it can be frustrating but when things are like my activation recently they are downright demoralizing…

So I had an evening free and wanted to do some POTA so I decide to setup in the truck with my hamsticks … since it is faster… you know since everything is ready to go. Little did I know what I was about to get into.

So I goto the frisbee golf parking area and get everything out to do an in-truck activation. This is how I operate if it is raining and has worked well for me in the past. I just tape a “rain shield” to the coax connector made from a peanut package with both ends cut out. Haha, reuse at its finest. But today, I didnt need it since it was not raining.

Next I break out the Ten Tec Argonaut 5 and my N3ZN cw key and connect it with my HamGadgets PicoKeyer and I am all set. Another thing with today is I planned to activate with my 8Ah LiFePO4 battery to see if it can handle an activation with the Argonaut 5. I have my inline power meter this time so I can monitor the voltage too. I also can monitor Amp/hour usage but completely forgot to do this since I got wrapped up in other things. I setup this kit in the cab of the truck as you see so that I could sit comfortably while being in the truck. This works really well when I am solo, but gets tougher if I bring someone with me. As you can see below it was up to almost 3 Ah by the time I took this photo. I wished I had thought to get a photo of it at the end to have that data. I guess I will have to do it again… lol.

But before all this got started I connected my antenna and wanted to check the SWR before starting as I have been experimenting with the radials some here lately and have learned some interesting things about them. I get out my nanoVNA and connect it to the antenna and it shows like it isn’t there…at all. I mess with the VNA a while and try to see if it might have a loose adapter on the VNA or if the calibration might have been done wrong, which I found not to be the case after calibrating it again… Nothing in the VNA was wrong, so I get out of the truck and inspect the antenna and it looks right, nothing is out of the ordinary. I go back and get my trusty little multimeter and decide to ohm the center pin of the coax to the shield to see what it measures, it should be open to the meter…it isn’t, quite the opposite actually, it is shorted. So I immediately go to the antenna and disconnect my brand new, reputable brand coax and check it with it removed from the antenna, it measures good now. Whew! That was close! I didn’t want my new coax to be bad right out of the chute.

So now that I am pretty sure it isn’t the coax, I turn my attention to the antenna. I remove the radiator and test the base to center pin and it reads shorted!! What in the world is going on here!?!? I look closely at the mount, which at this point has the BNC to PL259 adapter on it and nothing else and so I remove the top portion of the antenna mount to make sure water has not entered the plate where it passed through and has created a path with corrosion to the mount. Nope, not there, it looks perfect.

So I remove the adapter and the short goes away immediately. I reinstall it and it returns. I remove the adapter and check it and it measures fine and so does the antenna mount now. What gives? Well, I had a new adapter I picked up at the hamfest from the Wireman and I just installed it to see what would happen. The problem vanished. I tried wiggling the antenna and the coax and pushed and pulled on the adapter and the meter didn’t change a bit, all I can figure is that something in the other adapter is shorting when the adapter bottoms out on the antenna mount at the point where it gets tight.

This is what went bad. On the surface from every angle it looks perfect, but when tightened in place it produces a dead short across the antenna to ground. Don’t blindly think that simple things like this can’t fail. Obviously they can. I will be more diligent in checking my system routinely too. The Argonaut 5 has no SWR meter on it, which is pretty much the only thing about it I don’t like, so I have to use other means of monitoring the SWR. The VNA was that tool today.

Once that was sorted out, I was able to get on the air and make some contacts. Since I was dancing with the end of the UTC day, I figured I would start on 20 meters to improve my odds of getting an activation before the day flips over. The hunters came in clutch and I EASILY made the activation. Once I cleared all the calling stations, I QSYed to 17 meters to see what I could do there as the band was open earlier…before I found the bad antenna adapter…

Turns out 17 meters right during grey line to the west coast will net some cool contacts. All but one are from the west coast and that is always fun as I rarely get to work California due to noise on the bands. All in all, I netted 41 contacts in the log all before the UTC day ended. So it all worked out anyway. Moral to the story is two fold. The first one is to take extra parts for your system and two is don’t assume anything… this adapter looked perfect visually but did not work when installed. Have fun y’all and I hope to hear you on the air soon.

PS: Another perk to working POTA is things like these photos I grabbed of the clouds. You normally don’t see these at home in the house. If I had stayed home or threw in the towel on the antenna (which I almost did) I would not have seen these beautiful sunset clouds.

73 de WK4DS