WK4DS Amateur Radio Blog
My first POTA 2fer, with a QRP radio, and a Solar Storm!
Today I activated US-0716 (Chickamauga Battlefield) for my first-ever POTA 2fer! Between solar storms, parking challenges, battery failures, and meeting Dan (K2DTS), this activation had it all. Here's what happened when Murphy's Law met a QRP radio during less than ideal conditions!
Today saw the old red Chevrolet transporting my POTA gear over to Chickamauga Battlefield National Military Park which is park number US-0716. I have activated this park many times in the past, but unbeknownst to me was that the location I usually used to activate this park also allows for the activation of the Trail of Tears National Trail as well as it follows old HWY 27 right through the park! I have been activating a 2fer for years now and had no idea…live and learn.
This “parking lot” has only 2 spaces in it, but it is close enough in proximity to the main road to allow for a 2fer when activating POTA
I arrived on station to find that only one spot was available and no one around the truck. This matters as Dan (K2DTS) had mentioned dropping by to see the CW setup and to observe a CW activation for a little while. Turns out the car in the other space was not him. He would arrive later, which was a much needed “shot in the arm” to lift my spirits. You see, today was one of those days when the sun was really angry while I was setup to activate. The solar K index was either 5 or 6 which isn’t good…especially for QRP… My QSO count today was not all that high, but I still had a relaxing and fun time at the park none the less.
This location works well with my truck mounted antenna setup that I built. I used my old reliable hamstick collection today to get on the air and true to form, they worked pretty well. I have also refined my tuning system as well. I will give you the quick rundown on how I do it now. This works especially well with hamsticks as you will soon see.
Hamsticks are a very viable antenna system for POTA activators. They are easy to setup and work reasonably well for their tiny size. They usually have good power handling so digital modes like FT8 and even good ole CW are not a problem for them. Of course SSB is always fine if they can handle CW…
My Hamstick Antenna System and Color Coding Setup
Above is my modest hamstick collection to date. This is the 5 bands I use the most and I wished I also had the 10 meter version as well…but I digress. It is a good idea to do something to tell them apart. The labels are not very durable from what i have seen and so I chose to color code mine with various colors of electrical tape instead. Red - 40meters; Blue - 30 meters; Yellow - 20 meters; Brown - 17 meters; and Green - 15 meters. These are what I have been using for a long time now and they work well. These are made by three different companies too so the brand doesn’t really seem to matter. I have also converted mine over to the QD attachment design so that I can change bands fairly fast…well it is faster than threading them into the socket…haha. I have owned and used this exact setup for quite some time now as you can see from this blog post I wrote a good while back.
I also store them inside a PVC pipe I made into a storage tube. It is almost 8’ long so I can keep the “stingers” on all the base load coils which prevents me from mixing the wrong tip with the wrong load coil. I built this tube steel mount to fit inside the 2” receiver on a pick up truck, this allows for it to do two things at once. 1) It allows the antenna to be setup quickly and easily on any vehicle with a standard receiver mount. 2) I also built it so that it makes the base of the antenna at around 6’ above the ground. Getting the antenna higher does help with take off angle so I made the decision to make it taller than most. This also made it possible to string some radials at various angles so I can play with the impedance by adjusting the radials. If you look close in the lower photo, you can just see the radials connected to the base of the mount and running down out of the frame. These were tuned for 17 meters like this and they worked incredibly well in this configuration. When you only have a few watts like with the Penntek TR-35, you need all the help you can get…haha.
17 meter hamstick deployed during a POTA activation for CW and FT8 use. You can also see the highway in the background that is designated the Trail of Tears trail as well.
I setup in the passenger seat again, but to be honest, this was not ideal. I struggled to get all the stuff connected and stationary today. I also had a problem with the battery in the little power pack I had built…it was completely dead for some reason. I had used it recently but I didn’t think I had tanked it, anyway, not to be dissuaded I decided to get out the 8Ah battery and find a spot for it as well so I could power the station. You see, I needed the “power pack” so I would have a speaker. I figured that since Dan was going to drop by and hand out some, that I would make it to where he could hear the CW as well. This setup finally settled in and I was able to get on the air. This is when I figured out that the sun was angry…
I looked on the POTA spot page to look for a clear spot and there was only one other ham on the spot page, on 20 meters, in the middle of the day… Do you understand what this means? 20 meters is literally the honey pot of the HF bands when it comes to POTA. There is literally 2 dozen CW ops at times on this band and then there will be 2 on 17 meters. It will be that drastic and today there was me and one other guy in the Carolinas and that was it. Optimistic that I could at least get my ten in short order, I fired up the radio, dialed through the literal ghost town that was 20 meters and settled on a frequency around 14.063mhz and started calling CQ. It took about an hour to get my ten plus a few more, but I finally got them. In an attempt to get some stations I could hear in the noise, I even switch to headphones as you can hear MUCH weaker signals if you goto headphones over the external speaker that I am using. This trick didn’t work either as it turns out, that there has to be stations on the air for you to actually hear them… I had seemingly forgotten this minor detail on this day…lol.
POTA CW station ready for use, including the Penntek TR-35, home brew S meter and battery pack/ speaker combo unit. Also the Gemini travel CW key and the Dell Inspiron computer with HAMRS for logging.
CQ Ham Radio - Gemini travel CW key is really well designed and cost effective. This is one of my favorite CW keys when I dont have a surface to set the Begali Traveler on.
The Gemini CW Key: A Collapsible Treasure from eBay
Let me introduce you to one of my favorite travel CW keys that I use for POTA operations. This is a key I bought off of eBay initially and as of this writing, it seems to be the only place to get one of these keys now. Maybe an opportunity for a creative solution here… lol. Anyway, these are darling little keys that work beautifully and I always enjoy getting this one out. As you can see below, the reason I like this key is how it stows the handles when not used. You simply loosen the screw on top a little, slide the screw to the rear and this collapses the paddles inside the housing which protects the from damage when stored in less than ideal conditions. This key also is dead simple, lacking any sort of adjustments at all, you just plug it into the radio and use it. I like that to be honest…
GHD CW Key for portable CW operations like POTA.
Operating QRP During a Solar Storm (And Why 20 Meters Was a Ghost Town!)
So after I struggled around for a little over an hour to put 15 calls in the log…well…14 since one was a dupe… (duplicate calls on the same band, park, day and mode dont count to your POTA score)…I decided to put up the headphones and get out the HF Signals sBitx and work some FT-8 on 17 meters. I had not seen Dan so I figured the honey-do list got him or something and put away the CW gear while FT-8 hummed along in the background.
A lot of times, I will run FT-8 while I do house keeping chores like putting up radio gear from a different mode that I had just finished using or talking to the wife on the phone about what she wants me to do next after I finish playing radio… you get the idea. I can do some other things while keeping an eye on the display and letting it run in auto mode for a while. Well, not today buckaroo, seems the band were so bad that I couldn’t get auto to work today very well. I called CQ for a while to no avail. I finally started hunting other stations can answering their CQ instead. Switching to this tactic netted me 5 more contacts before I closed out the log for the day. 18 valid QSOs will do just fine…actually, 36 since I activated the 2fer today!
If you will notice the waterfall in the photo below, you will see that there really were not that many stations on the FT-8 segment…which is usually choked pretty tight with stations. The bands were just that bad. Even with these terrible conditions, I was still able to get 5 calls in the log for today on FT-8!
sBitx by HF Signals is a SDR powered by a Raspberry Pi 4 or Pi 5 SBC and does all sorts of things a regular radio can not do.
Meeting Dan (K2DTS) and the Ham Radio Community
While I was taking some of these photos and cleaning up the unneeded ham gear after switching to FT-8, look who stopped by to say hi and see the station! Dan (K2DTS)! He missed my CW portion of the activation and instead of setting it all back up, I did show -n- tell with him about all the gear I had brought to the activation. You have to understand that this is fairly substantial…haha. We talked for probably 20 minutes or maybe even a little longer about all sorts of things and had a great eye-ball QSO. I hope we can link up again at some point so I can get him on the air with CW so he can make some contacts too.
Ham radio is a wonderful community that has a large number of great people like Dan (K2DTS) who came out to the activation site today to see the setup.
Some days you don’t have to make a ton of contacts (although this never hurts…haha) to have a good time. Any day at a park with a radio is better than your best day at work. Knowing this I will always choose POTA over going to work… lol. Thanks for coming along today and I hope to work you on the air soon!
72
David - WK4DS
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Over 80 POTA QSOs in “less than ideal” conditions…
I activated US-2169 (Cloudland Canyon State Park) and made over 80 CW contacts despite lawnmowers, kids, and Murphy's Law doing its best to sabotage the activation. Here's what happened when "less than ideal" conditions tried to stop me!
Let’s talk about something that not a lot of people consider…what do you do when you get to a park and things are not like you imagined? Do you turn around and leave? Do you complain to park management? Do you setup and “get your ten” as fast as possible? What? Leave it in the comments what you do when you have problems like I did today?
POTA Park Conditions
Here is the setup, today I went to US-2169 (Cloudland Canyon State Park) to get on the air with my little Penntek TR-35 QRP radio and found some interesting things happening at the park today. As you can see below the weather was basically perfect for a POTA activation today. It is still early spring here so the top of the mountain is still not showing much signs, but the valley is getting ready…so to speak. Some trees are turning green and some of the dogwood trees are starting to bloom so we are getting started. The temperature was nice in the mid 60s today and it was sunny so it was really nice. I Did find the direct sun to be annoying to be honest as it kept causing a lot of glare on my computer which made it hard to see at times, but I powered through this first obstacle…
My POTA station for today consisting of the Penntek TR-35, the Begali Traveler CW Key and my Dell Inspiron computer for logging.
The next thing I ran into was the kids, there were so many kids in the park today, it must be some spring break or something as there were a lot of groups of children like you see in the photo above (in the background) and they were…well…being kids… This in itself isn’t a problem, but I failed to bring any sort of flagging tape to mark my coax with so I was constantly looking over my right shoulder to make sure no one was about to walk into it. Actually, I only had to do this for a little while as there was something else that happened a little later that basically ran the kids off for me… haha. The lawnmowers…
The POTA HF Radio System Setup - Reliance Antenna
Anyway, let’s look at the antenna setup today to see what made it work so well. I started with two throw lines today so I could elevate the whole antenna off the ground. You see, I was using the Reliance Antenna Bugout 40m EFHW again today and wanted to replicate what I had back in Florida.
Today saw me use the Reliance Antenna Bugout 40m EFHW antenna to great effect even with all the problems.
I threw a line about 15 feet up over a large limb on the nearby tree to create the first point and this is where the coax went up to the transformer. I didn’t use a tuner today so I stayed on 20 meters the entire time today.
POTA antenna installation showing the 1st elevated point of the antenna transformer from the operating position.
I ended up tying the antenna lift rope (it is actually a small cord but you get the point) to the grill right behind the table to the left in the above photo. I used a Velcro tie to attach the end of the coax to the “possibles” bag on the table as it is heavy and the coax is really light and I figured it would hold it just fine…which it did. Next came the haul line to lift the antenna into the distal tree with the high end about 30 feet up. I use a stainless steel throw weight that I made in the machine shop so I can send this thing into the stratosphere if I want…haha. The wide angle photo below shows where the antenna was in the trees. You can also see another family at the picnic table in the background… more kids… haha. The good thing about using two haul lines in that the entirety of the antenna is WAY above where anyone could even get close to it. I was also using QRP power so there was no danger of RF issues here. The height is also beneficial for propagation and we will see a little later that it did in fact help.
Now, this antenna doesn’t have a counter poise of any kind so it uses the coax shield for the counter poise. To keep the stray RF out of the radio, I use a special coax from ABR Industries that has a ferrite common mode choke in one end. I simply put this end on the radio side and this allows the antenna to access the coax shield for counter poise use and also it keeps the common mode currents out of the radio… At least that is what I hope is happening, the strategy seems to work so I am running with it.
Position of the 40m EFHW antenna today for my POTA activation. Well above the ground!
POTA Activation Highlights
So once the radio was all put together and powered up on the table, I connected the speakers from my custom built project. This is a power pack with a 3aH Bioenno battery in a project box with a power-pole receptacle and a set of speakers so the Penntek TR-35 can be used like a regular radio since it has no internal speaker. I like running it like this if the ambient noise level is low enough as it allows the people around me to hear the CW as well. This sometime sparks interest and people will come over and ask me about what I am doing. A perfect5 opportunity to share with someone about amateur radio.
I started listening around a little and found 14.061mhz was clear after listening for a while. I have found that I will hunt me a clear frequency then get out the logging computer, boot it up and get the software running and ready to use, then I will spot myself on the POTA app all prior to sending that first CQ call. If you do any of this after sending that first call, you had better finish before the radio memory buffer does… that is all I have to say about that…lol. Just like clock work, I got an answer on the very first call too! I worked about 15 or 20 stations in pretty short order and then the QRM started. Someone decided that a QRP operator in the QRP portion of 20 meters activating a POTA park with a valid callsign was completely unacceptable for some reason. At first (read that as “for the first 5 full minutes” I actually thought they were just either missing me and sending their call twice or couldn’t hear me or something. You see, I was working stations the whole time! haha. So I finally stopped and listened and this person was sending real CW so it was someone who went to the trouble to actually learn it. But here is what they were doing, they would send a random letter, wait 3 to 4 seconds and send another random letter and then wait some more then do it again. All it really did to my normal QSO pattern was have me simply send everything twice as the spacing they were using allowed for this perfectly. Then I would send a CQ out of my keyer memory as the Penntek TR-35 has 2 keyer memories built into it. As soon as the CQ would start I could hear them in between my characters trying to jam me, so I would simply hit the keyer a second time and let it send the WHOLE message again and by then they either realized I was using a memory keyer or got tired of competing with a machine and would stop…till I would send a signal report. LOL. Remember what I just said about the cadence and my tactic to combat it? Well, I think they finally gave up at around QSO number 50 or so.
POTA station consisting of the Penntek TR-35, homebrew “S” meter, homebrew powerpack with speaker, Begali Traveler CW key and Relianca Antenna wtih ABR Industries Coax
Murphy’s Law at Work during a POTA Activation
That’s right, I made about 30 contacts while the QRMing op was actively trying to sabotage my activation. lol. So while this was going on, there was another “storm” brewing in the background… the lawnmowers had arrived…
State park grounds keepers doing lawn maintenance.
They had been in the distance, but at this point they were starting to get closer and closer… At this point I am starting to think that these guys have been hired by the guy messing with me on the air! It was like they had been signaled or something. Just about the time the QRM vanishes, they show up!ll, to start with they were mowing over on the far side of the area so it was mildly annoying but not a real problem for my operating…but then…
State park employee doing lawn maintenance while I activate POTA at US-2169 Cloudland Canyon State Park.
You guessed it, they felt it imperative to cut the dead leaves in the picnic area RIGHT BESIDE ME!!! Do you see any grass in that site?? I sure didn’t, but he sure was mowing it! Good grief, this is starting to get out of hand at this point and the sound of the engines was so loud that I had to resort to ear bud headphones to be able to hear. This did mitigate almost all of the noise from the mowers but it didn’t do anything for the dust cloud they were stirring up. Good grief.
David - WK4DS resorting to headphones due to high noise in the local environment during POTA at Cloudland Canyon State Park
By this point I had almost 80 QSOs in the log so I set a goal of getting 80 counted QSOs to go towards my goal of 10,000 which meant accounting for the dupes in my log, of which there were many today. You see I had been there for several hours at this point and some stations had wandered by me a couple of times. I know I worked one station 3 times today, but so is life sometimes. I no longer tell people I have them in the log, I automatically assume one of two things have happened.
The first one is that I could have gotten someone else’s call wrong and therefore I now have the legitimate call on the hook at that moment. (very possible with my poor hearing at times) The second is that they simply don’t realize I have them in the log. So I work them again and log it again and simply let HAMRS record it as a dupe and move on with life. It doesn’t hurt anything to log them again, other than the time it takes, so I simply complete the QSO as if it was the first time. No harm, no foul.
CW and North America came in clutch for this POTA Activator today!
Today saw me work over 80 calls and of those exactly ZERO were outside of North America. I worked a couple of Canadians but other than that, the rest were US operators only. Not a single DX station at all. It could be one or more of several factors I guess. I did put over 80 calls in the log for today and that is a great day despite all the various things that attempted to stop me. haha. In the end, it was still a wonderful day and I had a great time with my tiny little Penntek TR-35, my Begali Traveler CW Paddle and the Reliance EFHW 40 meter antenna. What a great little setup! Portable, light weight and best of all, it works! What do the old timers say? “Five watts and a wire…” Yeah, it will absolutely work if you will go when the bands are open and just try…
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72 - WK4DS (David)
Ten watts to Spain. Ten watts to Germany. Ten watts to Austria. The EFHW at 35 feet made all the difference.
Activating Hillsborough River State Park (US-1878) with a friend is one thing—making over 100 contacts in a single afternoon using QRP power and a homemade wire antenna is another. That's exactly what Chas and I accomplished using a 65-foot EFHW antenna strung 35 feet up in the Florida pines, a ground mounted vertical, his FT891, a Penntek TR-35, and my sBitx v3 running just 10 watts (Chas was running 50 watts today though). This wasn't just a Parks on the Air activation—it was a field test of how well minimalist gear performs in a multi-operator setup, complete with lessons learned about antenna placement, front-end overload, and working around the Florida sun.
Activating Hillsborough River State Park (US-1878) with a friend is one thing, making over 100 contacts in a single afternoon using QRP power and a homemade wire antenna is another. That's exactly what Chas (NA2B) and I accomplished using a 65-foot EFHW antenna strung 35 feet up in the Florida pines, a ground mounted vertical, his FT891, a Penntek TR-35, and my sBitx v3 running just 10 watts (Chas was running 50 watts today though). This wasn't just a Parks on the Air activation, it was a field test of how well minimalist gear performs in a multi-operator setup, complete with lessons learned about antenna placement, front-end overload, and working around the Florida sun.
Hillsborough River State Park entrance designated K-1488 for Parks on the Air activations.
Hillsborough River State Park: Location and Access
Hillsborough River State Park sits about 12 miles north of Tampa and makes for an excellent POTA location. When you arrive at the entrance, the first thing you're greeted with is a ranger station where you pay your four dollar entrance fee. Yes, you read that right—four dollars for the whole day. This is a really nice park with extensive hiking trails, a large loop perfect for biking, and the Hillsborough River running through it where visitors can enjoy boating and fishing.
There's plenty of infrastructure here for families… playgrounds, picnic areas with covered pavilions, and well-maintained facilities. For POTA activators, the key feature is the abundance of tall trees throughout the park, making it ideal for wire antennas. The main loop road has several pull-off areas with picnic tables that work perfectly as operating positions. Cell phone coverage is good throughout the park, which helps for spotting yourself on the POTA network and coordinating with other operators.
After paying the entrance fee, I drove around the loop a couple of times while talking to Chas on the phone, trying to figure out where he'd set up. Here's the kicker, though, he decided to drive over to my location so we could operate together from adjacent tables. This gave us the multi-operator experience but also taught us some valuable lessons about antenna placement and RF interference, which I'll get into later.
The 65-foot EFHW antenna strung into the tree canopy (highlighted in yellow) getting the wire 35 feet high made a dramatic difference in propagation. The wire itself is nearly invisible against the tree background.
The Antenna Setup: 65-Foot EFHW in the Trees
Today saw the use of a 65-foot long wire antenna, an End-Fed Half-Wave from Reliance Antennas. This antenna isn't rated for high power, so I held all of my transmit power to 10 watts or less throughout the day to prevent potential damage to the matching transformer. We deployed it using throw lines to get it about 35 feet up into a large oak tree, then Chas loaned me his 10-foot push-up pole and stand to support the feed point end of the antenna and get it a little higher off the ground as well.
I believe this additional height aided propagation dramatically. Getting the whole 40-meter EFHW that high off the ground, with the far end even higher in the tree, made a noticeable difference compared to previous activations where I'd run antennas lower. I made many contacts all over the United States, into Mexico, and even worked some European stations on the higher bands with just 10 watts. That's the magic of getting a wire antenna up high… height matters more than power in many cases.
The EFHW is resonant on 40m, 20m, 15m, and 10m without needing an antenna tuner, which keeps the station setup simple. I specifically avoided the WARC bands (30m, 17m, 12m) during this activation because the antenna isn't cut for those frequencies and I didn't want to deploy a tuner. Sometimes keeping things simple is the better approach, especially when you're testing equipment and learning how gear performs in the field.
The ranger station where you pay the $4 entrance fee to access the park for POTA activations.
Radio Gear: Penntek TR-35 and sBitx v3 Performance
Once I had the antenna set up and tested, I decided to use the Penntek TR-35 transceiver first. I really enjoy using this tiny little radio, the CW break-in is phenomenal, and the keying from the internal keyer circuit works flawlessly. It's a true QRP radio putting out 5 watts maximum, and I've made some additional accessories for it to turn it into a more complete field station. But even as it sits stock, it's a wonderful little radio that's almost impossible to damage from bad antennas or other field mishaps. Plus, it just works really well at making contacts.
I started on 40 meters and after working through a good run of stations, I decided to move up to 20 meters where activity was heating up. Chas started on 30 meters and worked his way through the WARC bands, eventually ending up on 10 meters where we made a park-to-park contact with each other from 30 feet apart. That was pretty funny, logging a P2P (park-to-park) contact when we could literally see each other across the operating area. I turned my output power all the way down, it showed literally zero output and I was still booming into Chas’ radio!!! Haha!
After finishing my run on 20 meters with the Penntek TR-35, I swapped it out for my sBitx v3. I throttled the output power on the sBitx for two reasons: first, to prevent damage to the antenna which isn't rated for high power, and second, to keep from running down my battery too quickly. I'd brought an 8 amp-hour LiFePO4 battery, and if I'd run the sBitx at full output power I could have easily depleted that battery in an hour or so, especially running FT8 on the lower bands which requires more transmit time. As it turned out, limiting power to 10 watts kept the battery happy all day and I still had plenty of capacity left when we packed up.
Initial station setup with the Penntek TR-35, Dell laptop for logging, clipboard with paper log, and CW paddle ready to make contacts.
The first thing I did with the sBitx was get on 15 m and attempt to make contacts there on FT8. This went pretty well and I made several contacts on 15 m before moving to 10 m to see what I could make on that band. The reason I skipped the WARC bands today was because this antenna is not resonant on any bands other than 40, 20, 15, and 10 m. So I stayed on those bands as I did not want to try and deploy an antenna tuner as well.
The sBitx v3 with improvised sunshade, Florida sun glare was a constant challenge throughout the activation. Notice the notebook to keep my arm off that rough concrete!
Contact Statistics:
Between Chas and me, we logged 118 total QSOs during the activation! 66 in my log and 52 in Chas's log(I did operate a little longer than him and we were not in a race either). Here's my detailed breakdown:
David's Stats (WK4DS):
40 meters: 5 QSOs (all CW)
20 meters: 50 QSOs (all CW)
15 meters: 1 QSO (CW)
10 meters: 10 QSOs (8 FT8, 2 CW)
Total: 66 QSOs
CW: 58 contacts
FT8: 8 contacts
Geographic Breakdown:
Domestic (USA): 56 QSOs across the continental United States
DX (International): 10 QSOs reaching six countries:
Spain: 2 contacts (EA4T, EA5BCO)
Germany: 2 contacts (DL4JCP, DJ9HX)
Mexico: 2 contacts (XE2BCS, XE2IF)
Austria: 1 contact (OE2IGP)
Canada: 1 contact (VE1ZZ)
Poland: 1 contact (SQ9JS)
Czech Republic: 1 contact (OL26WRTC - special event station)
NA2B Chas's Stats: Chas logged 52 QSOs throughout the day, primarily working 30m, 17m, and 10m (he might have done more but that is all I know of) while I focused on 40m, 20m, 15m & 10m. This band coordination helped us avoid stepping on each other while maximizing total contacts for the activation.
Combined Performance: For QRP power (my 10 watts maximum and Chas running 50 watts) and simple antennas, 118 total contacts in one afternoon represents excellent POTA performance. The 10 DX contacts on 10 meters with just 10 watts and the EFHW antenna particularly stand out, working Spain and Germany on FT8, then switching to CW for additional European contacts, demonstrates what's possible when propagation cooperates and you get your antenna up high.
Twenty meters was the workhorse band, delivering 50 contacts in my log alone. The concentration of activity on 20m CW (14.061 MHz) is typical for POTA activations, as this is where most hunters are listening for parks. The handful of 40m contacts at the start of the activation caught the tail end of daytime propagation before that band shifted to primarily short-skip domestic contacts.
Operating Challenges - Sun and Glare
Both Chas and I learned pretty quickly that the Florida sun was not our friend today, even though the temperature was pleasant. The glare from the sun continuously made us struggle to see our displays and adjust settings. I think Chas literally just toughed it out and lived with squinting at his screen. I, on the other hand, kept deploying improvised sunshades and repositioning my station to create shade for my equipment as the day wore on, as you can see in the photos. This is something to think about when planning a POTA activation, a simple popup canopy or umbrella can make the difference between comfortable operating and constantly fighting the sun. Add that to my growing list of field operation lessons learned.
sBitx v3 CW Keying: Improvements and Remaining Issues
The CW keying in the sBitx has been dramatically improved as the software revisions continue. The developers keep optimizing the scan time of the Raspberry Pi processor and how the program executes, making the keyer more responsive with each update. It's almost like using a regular radio now, though there are still quirks you need to work around.
I've learned that I have to pay very close attention to my sending cadence when working CW with the sBitx. The keyer isn't as forgiving as a traditional Curtis-style keyer circuit, and it will send errors if you're not careful with your timing. Knowing this limitation, I work much harder to stay at one speed setting throughout a contact when possible. It's easier to develop muscle memory and consistent sending rhythm at one speed rather than constantly adjusting the keyer speed up and down as I might do with other radios.
With a traditional Curtis keyer, minor variations in your paddle timing get smoothed out by the keyer circuitry and everything sends cleanly. The sBitx will occasionally miss characters if you vary your speed too much, if you slow down suddenly, you can actually outrun the radio's keyer circuit and it won't register that you asked for a "dit," so it leaves it out. This isn't a deal breaker, but it does mean the sBitx requires more disciplined sending technique than most modern transceivers.
I do tend to make more mistakes with the sBitx than I do with other more traditional Morse code radios, and I think all of this traces back to the timing limitations from the Raspberry Pi's scan cycle. But it's getting better with each software update, and for a radio that does CW, SSB, and all digital modes in a package this small and affordable, I'm willing to work around the keyer quirks.
Chas operating his Yaesu rig from the adjacent picnic table. His vertical antenna is behind me and to my right. My wire antenna is behind him.
My operating position in the foreground with Chas visible about 30 feet away in the background—close enough for a park-to-park contact but creating some RF interference challenges.
20-Meter Band Issues: IRF520 vs IRF510 Amplifier Problems and Receiver Front End Overload"
The final two photos show a couple issues I've been wrestling with on my sBitx. The first image shows my sBitx operating on 10 meters with lots of noise lines visible in the waterfall display. These noise lines are coming from Chas transmitting Morse code on a different band, his signal is getting into my receiver and creating visible interference. I don't remember exactly what band he was on, but the important lesson here is that antenna placement matters tremendously when you're running multi-station setups like this one.
sBitx running FT8 on 10 meters (28.074 MHz) showing the noise spikes from Chas transmitting on a different band nearby 9in the waterfall) this is what front-end overload looks like in a multi-op field setup. The vertical lines in the waterfall are RF bleed-through from his station 30 feet away.
Be mindful of where you place antennas if you're operating a multi-operator event. We were only 30 feet apart, which is far too close for optimal isolation. I was still able to work many contacts even with this persistent noise coming through, though. This is something you learn to work around if you're going to be an amateur radio operator in a multi-operator event of any kind…think Field Day here. It's just part of the game, so you expect it and adapt. We could have used bandpass filters to eliminate most of this interference, but I didn't bring mine to the park.
The next photo shows my sBitx on 20 meters, and on 20 meters my radio has a persistent issue that I'm still troubleshooting. I'm beginning to believe it has to do with the IRF520 MOSFET transistors that I used in the power amplifier section when I built this radio. These IRF520 transistors have significantly more internal capacitance than the IRF510 transistors that Farhan originally specified in the revised amplifier design. I think this extra capacitance is causing the amplifier to oscillate, and that oscillation is what you're seeing as the noise signal in the photo.
sBitx on 20 meters CW mode (14.061 MHz) showing the noise from what I am suspecting is from oscillating mosfets.
Here's the interesting part: as the radio warms up during operation, this spurious noise signal moves down in frequency within the 20-meter band. If I want to push it out of the way temporarily, I'll switch to 40 meters or 80 meters and run FT8 for a few minutes. You generate more output power on those lower bands, which heats up the amplifier section faster. Usually, if I just run FT8 first thing when setting up, it warms up the transmitter enough to push the oscillation down to below where I normally work CW on 20 meters anyway, giving me a temporary workaround.
This isn't a permanent solution, obviously. I'm convinced I'm going to have to address this capacitance issue when I get back home, probably by swapping out the IRF520s for the specified IRF510s or adding additional filtering to the amplifier circuit. But for now, knowing the workaround lets me keep the sBitx operational in the field for POTA activations, which is what matters most.
Multi-Operator Challenges: RF Interference and Antenna Placement
Operating two stations in close proximity taught us several valuable lessons about multi-operator setups. The biggest challenge was RF interference between our stations. With antennas only 30 feet apart, we experienced significant front-end overload, when Chas was transmitting on his station, I could see his signal bleeding through into my receiver on completely different bands.
The sBitx has a somewhat easy-to-overload front end compared to more expensive commercial receivers, which made this problem more pronounced. But even with a better radio, operating this close together without bandpass filters or careful band coordination is asking for trouble. The solution for future multi-op activations is simple: either space antennas much farther apart (100+ feet minimum if possible), or operate on bands that are far enough apart in frequency that filter roll-off provides natural isolation.
The position of your antennas matters just as much as the distance between them. If we'd oriented our antennas at right angles to each other instead of parallel, we might have achieved better isolation through pattern nulls. These are the kinds of things you learn by doing, and they apply equally to Field Day operations where you might have multiple stations running simultaneously.
Despite the interference challenges, we still made excellent contact numbers. Multi-operator POTA activations are worthwhile because you can cover more bands simultaneously, operate different modes at the same time, and keep the activation going continuously while one operator takes a break. Just be prepared to work around the RF challenges that come with the territory.
Who Should Activate This Park?
Hillsborough River State Park is an excellent choice for both first-time and experienced POTA activators. Here's why:
For beginners: The $4 entrance fee is minimal, facilities are excellent with clean restrooms and covered picnic areas, and the tree coverage makes wire antenna deployment easy. You don't need to hike to reach good operating locations…everything is accessible by car right off the main loop road.
For experienced activators: The park's location north of Tampa puts you in a good spot for both domestic and DX contacts. The tall pines support wire antennas at significant heights, and there's plenty of space to spread out if you're running a multi-operator activation.
Best practices for K-1488:
Arrive early morning (8-10 AM) or late afternoon (3-5 PM) to avoid midday heat and sun glare
Bring sunshade or canopy, there's limited natural shade at the picnic tables
Plan for 2-3 hours of operating to get a good contact count
Cell coverage is good for self-spotting on the POTA network
Spring and fall offer the best weather conditions
If you're in the Tampa Bay area and looking for an easy, productive POTA park with good facilities, Hillsborough River State Park should be on your list.
Activating Hillsborough River State Park proved to be a highly productive POTA outing. Between Chas and me, we logged well over 100 contacts using QRP power and simple wire antennas…proof that you don't need high power or expensive gear to have success in Parks on the Air. The 65-foot EFHW at 35 feet worked exceptionally well, the Penntek TR-35 remains one of my favorite field radios for CW, and the sBitx v3 continues to impress despite some remaining amplifier quirks on 20 meters.
Key lessons learned: antenna height matters more than output power, multi-operator setups require thoughtful antenna placement to avoid interference, and limiting transmit power to 10 watts keeps your batteries happy all day. If you're looking for a beginner-friendly POTA park in Florida with good tree support and easy access, Hillsborough River State Park (K-1488) is an excellent choice.
Have you activated K-1488 or other Florida state parks? Share your experiences in the comments below, I'd love to hear about your favorite POTA locations and antenna setups.
Want more POTA activation reports and technical amateur radio content? Check out my other WK4DS blog posts for detailed equipment reviews, antenna builds, and field operation tips.
Frequently Asked Questions About POTA Activations
What is Parks on the Air (POTA)?
Parks on the Air is an amateur radio operating activity where hams set up portable stations in state and national parks to make contacts. Activators (operators in parks) try to make at least 10 contacts to qualify the activation, while hunters (operators at home) try to contact as many parks as possible. It's similar to Field Day but focused on public parks and conservation areas. POTA encourages hams to get outdoors, test portable equipment, and promote amateur radio to park visitors. The program started in 2016 and has grown to include thousands of parks across the United States and internationally.
How do you activate Hillsborough River State Park for POTA?
To activate Hillsborough River State Park (K-1488), you need to set up your amateur radio station within the park boundaries and make at least 10 contacts. Pay the $4 entrance fee at the ranger station when you arrive, then find a suitable operating location with trees for antenna support. Most activators set up at picnic tables near the main loop. Operate from battery power or a generator, no AC mains allowed for POTA activations. Log your contacts using a smartphone app like HAMRS or POTA Logger, then upload your log to the POTA website within a few days. The park has excellent tree coverage for wire antennas and is open from 8 AM to sundown year-round.
What is an EFHW antenna and why use it for POTA?
An End-Fed Half-Wave (EFHW) antenna is a wire antenna that's fed at one end through a matching transformer (typically a 49:1 unun), making it incredibly easy to deploy in the field. For POTA activations, EFHWs are popular because they require no ground radials, work on multiple bands without a tuner if cut for harmonically-related bands, and can be thrown into trees using a throw line and weight. My 65-foot EFHW works on 40m, 20m, 15m, and 10m, covering the most productive POTA bands. Getting it 35 feet high significantly improved propagation compared to running the same antenna closer to the ground. A properly deployed EFHW antenna at height will often outperform a vertical antenna at ground level for DX contacts.
Can you run two stations at the same POTA activation?
Yes! Running multiple operators at the same park location is allowed and encouraged in POTA. Each operator logs their own contacts and submits their own activation log. Chas and I each operated our own stations about 30 feet apart, which let us cover different bands simultaneously and maximize the total contact count. However, you need to be mindful of RF interference between stations. With our antennas so close together, I experienced front-end overload on my sBitx when Chas was transmitting on nearby bands. Solutions include better antenna separation (100+ feet apart if possible), using bandpass filters on receivers, or coordinating to operate on widely separated bands like 40m and 10m simultaneously.
What's the best QRP radio for POTA activations?
For CW-only POTA activations, the Penntek TR-35 is exceptional. It's lightweight (under a pound), battery-efficient, has outstanding CW break-in, and is nearly indestructible, perfect for field operations. For multi-mode operation covering CW, SSB, and digital modes, the sBitx v3 offers incredible value and capability in a portable package, though the CW keying requires careful technique and practice. Other popular POTA QRP rigs include the Elecraft KX2/KX3 (premium price but premium performance and battery efficiency), QRP Labs QCX-mini (CW-only, ultra-portable and inexpensive), and the Xiegu G90 (good SSB performance, acceptable CW, built-in tuner). Choose based on your preferred modes, budget, and how much weight you want to carry into the field.
How many contacts should you expect from a POTA activation?
Contact numbers vary widely based on propagation conditions, time of day, your operating skill, and whether you're spotted on the POTA network. A successful activation requires at least 10 contacts to count, but most activations yield 20-40 QSOs in an hour or two of operating. Our 100+ contacts in one afternoon between two operators was excellent, partly because we covered multiple bands and modes (CW, FT8) and had good propagation to Europe on the higher bands. If you're new to POTA, expect 15-30 contacts on your first few activations. Using CW typically yields more contacts than SSB due to pile-ups from hunters chasing parks, and FT8 can be productive when propagation is marginal or when SSB isn't getting through.
My 66 contacts plus Chas's 52 gave us 118 total QSOs from K-1488 on February 17, 2026. Ten of mine reached six countries across two continents, all at 10 watts or less.
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73
David / WK4DS
Overall, today we had a wonderful day and made many contacts and was able to test antennas and enjoy ourselves in the warm Florida sun far from home where all the cold weather and dreariness is at. So until next time, get your radio out and go power it up and make a contact on it. That’s why you bought it after all.
Chas grabbing a photo from his perspective for posterity! HaHa! Look at all that stuff I brought!