Field Report: Testing the new Penntek TR-35 firmware during a POTA activation!

Since I have a busy family life, I always look for opportunities to fit a little field radio time into my schedule.

My policy is to always keep a radio field kit in my car or truck so I can take advantage of any last minute opportunities.

On the morning of Wednesday, April 20, 2022, I was scheduled to take my car in for warranty/recall servicing at the dealership.  I decided in advance that if the service could be completed in two hours or less, I’d relax in their waiting room with my MacBook, drink a cup or two coffee, and attempt to make a dent in my email backlog.

If the service was going to take longer than 2 hours, I decided that I’d use one of their loaner/courtesy cars and activate a nearby park.

The dealership is about 45 minutes from my QTH and I’ve activated most of the parks nearby it, save one: Holmes Educational State Forest.  I’ve been wanting to activate this park for ages, but my travels these days simply don’t take me in the direction of the park very often; it’s a good 75 minute drive from my QTH.

Uncertain how long the dealership would need my car, I grabbed my SOTA backpack that had a full field kit inside based on the Penntek TR-35 transceiver.

TR-35 Upgrades!

Why the TR-35? Because I was testing new firmware that added a huge upgrade: two CW message memories!

I won’t go into details about the new upgrade in this field report since I describe it both in my activation video (see below) and in this post which relays the announcement from WA3RNC.

Suffice it to say, I was itching to see how well the new message memories work during a proper activation.

Front of the line

Since this upgrade was just made public, I thought those of you who either own the TR-35 or are plotting to purchase the TR-35, might want to see it in action. For this reason, I pushed this video and field report ahead of all of the others in my pipeline.

The really weird part about publishing this video so quickly is that one of my next field reports and videos will actually feature the first time I took the TR-35 to the field about 3-4 weeks ago! Back then, CW message memory keying wasn’t even on the table.

Activation time

I arrived at the dealership around 9:00 AM (local) and the first thing I asked was, “So how long do you think this will take?” The representative looked at the work to be performed and said, “Three or four hours, likely. If you’re in a rush, maybe two hours.

I decided I wasn’t in a rush because I’d much rather be playing radio at a new-to-me park than sitting in a waiting room.

I asked if I could borrow one of their courtesy cars and he replied, “We assumed you might want one Mr. Witherspoon, so we already reserved one for you.”

Woo hoo!

Holmes Educational State Forest (K-4856)

The drive to Holmes Educational State Forest from the dealership took perhaps 30 minutes or so–it was a gorgeous day and a beautiful journey.

I’m a big fan of North Carolina Educational State Forests and have activated a few in the past: Tuttle (K-4861), Mountain Island (K-4858), and Rendezvous Mountain (K-4859). I love them because they typically have:

  • Loads of tall trees
  • Picnic areas
  • Excellent trail loops
  • Ample parking
  • Generally lower visitor density than major parks

Holmes has a large parking area that I pretty much had to myself when I arrived.

I explored the area a bit to find a nice activation spot.

The trails were beautiful.

Like Tuttle, Holmes also has a large covered outdoor classroom and picnic shelter.

No doubt a great rainy day activation spot (as long as the shelter isn’t reserved or occupied).

There are multiple picnic sites along a trail loop.

I found a few ideal picnic tables that, I could tell, are used much less than those by the stream. One, in particular, had plenty of space for my 40 meter end-fed half-wave.

Setup was quick and easy!


On the air

I had a feeling that this site might not have mobile phone service and I was mostly correct about that. The park is definitely on the fringe of the reception area for my carrier. Most of the time, my phone had no service at all, no matter how I positioned it. On occasion, it would get a brief lock on a tower–just enough to send a short text message, nothing more.

Before leaving the QTH that morning, I scheduled the park activation on the POTA site so that it would be able to auto-spot me using the Reverse Beacon Network (RBN).

I started calling CQ POTA around 14:50 UTC and within two minutes, I logged WB1LLY, AD8EV, and then NE4TN.

Then silence.

I thought that awfully odd, but this is where having CW message memory playback comes in handy–I simply pressed the AUX switch down quickly, then tapped the left paddle on my key and the TR-35 sent the message I recorded in advance: CQ POTA DE K4SWL.

Finally, NE4TN called again and asked for my park number. I sent it to him with thanks and then realized that the POTA site was not auto-spotting me. This explained the silence on the air. My guess is that the first three contacts might have discovered me via another system like Ham Alert.

I’m not sure if it was NE4TN or my buddy WD8RIF who manually spotted me, but I was very grateful they did. After a few minutes, I received a small pile-up of contacts which quickly took me over the 10 needed for a valid park activation.

In fact, by the end of the activation, and a total of 47 minutes on the air, I logged 27 stations (twenty one on 40 meters, six on 20 meters).

It was a most enjoyable activation and I’m pleased to report that the new CW message memory functionality of the TR-35 worked beautifully.

One other fellow who tested the new TR-35 firmware is John (AE5X). He just posted a field report and video on his excellent blog and pointed out that the spacing between words was just slightly long.  I agree and so does John (WA3RNC), so spacing was tightened up in the production firmware.

I already thought the TR-35 was a fabulous little rig, but CW message memory keying makes it an invaluable little CW field radio.

All new TR-35s will ship with the upgraded firmware, but if you already own the TR-35, read this previous post about how you too can get the upgrade.


Here’s what my 4-5 watts into a 40 meter EFHW looks like plotted out on a QSO map (click map to enlarge):

Activation video

Here’s my real-time, real-life video of the entire activation, save deploying the antenna (which I’ve done so many times in other videos):

Click here to view on YouTube.

Unsolicited Advice: Always have an RBN backup!

This activation was a prime example of why I always let my buddies Eric (WD8RIF) and Mike (K8RAT) know my activation plans. We watch out for each other in case the POTA-RBN connection isn’t working.

The RBN functionality on the POTA site (and SOTA) is simply amazing, but sometimes–very rarely, in fact–it is down. After all, it’s a complex system with a lot of moving parts.

Reality is, if you’re not spotted, you may struggle to get the contacts needed to validate a park activation. It can be very difficult because you’ll be relying on people to randomly discover then spot you.

Thank you

This was a really fun activation, and I’m happy I brought my radio gear.

I do love this TR-35 and I plan to just buy it from WA3RNC if he’ll let me. While I’d love to buy the kit and build it, I’ve gotten used to this one and have already modded it twice. (Indeed, I think I might add two little fold out feet like John did on his!). That and I will be first in line to buy the Penntek TR-45L kit when it finally becomes available.

As always, I’d like to send a special thanks to those of you who have been supporting the site and channel through Patreon and the Coffee Fund. While certainly not a requirement as my content will always be free, I really appreciate the support. It makes videos and reports like this one possible.

Here’s wishing everyone an amazing week, good health, and good propagation!

Cheers & 72,

Thomas (K4SWL)

18 thoughts on “Field Report: Testing the new Penntek TR-35 firmware during a POTA activation!”

  1. Beautiful day, and beautiful scenery! The TR45-L is certainly a cool-looking little rig, though I wish it shared the 35’s band. Hopefully WA3RNC can get the components he needs to put it into production.

    1. True–I find I rarely hop on 80 in the field, but I also see the TR-45L being used in the shack quite a bit.

      It is a cool rig, though, isn’t it? I love the analog meter!


    2. Actually, as intriguing as I find the TR35, I’m even more interested in the TR45-L. I’ve always had a soft spot for 80m, and while I like 17m, I’d prefer 80m even more. I’ve done QRP on 80 for decades, and in many ways, find it more enjoyable than 40m QRP (with all of the QRM I’ve had to deal with on that band over the years). A 100 foot end fed wire, a Z-match, and a counterpoise, will surprise you results-wise on 80m. I was very much leaning towards getting a TR35 kit (burt wishing that there was an 80m option available for it), but I think I’ll wait for the TR45-L to become available.

  2. Thomas,

    Excellent videos and blogs. I’m relatively new to CW and I really appreciate you taking the time to make these videos. Also, can you tell me what that digital “tape” recorder that is? That looks like and excellent idea. I assume you are using it as a speaker and a recorder. Thank you

    1. Hi, Brett,

      I’m so glad you find the videos useful for CW practice.

      The little Sony Recorder is a Sony ICD-PX-312 digital recorder. This is one I purchased last year at a thrift store for $20. I’m guessing it’s 10-15 years old?

      Basically, I record the line-in audio from the headphone port on the radio. That gets clean radio audio. I then sync it with the audio recorded from my camera so you are subjected to my dialog. 🙂 Ha ha!


      1. Hi Thomas,

        Your activations are my main source of CW practice. I love them. I watch via your YouTube video because I get a nice full screen of it all.

        But this time it doesn’t seem like the CW recording got synced up with the video recording. I couldn’t hear any CW on either end of the Q’s in this activation. I hear your comments just fine, as well as some birds in the background, but no CW at all.

        Thanks so much for all you do!!


        Ron, W6AZ

        1. Hi, Ron,

          It’s the weirdest thing, isn’t it?

          Someone commented yesterday on YouTube noting that the CW audio was missing. I checked the video and he was right: as you say, I could hear my commentary, birds, the wind, but no CW or audio from the radio, so I marked the video private so no one could open it until I figured out the problem.

          I then checked my original recording that I uploaded and the audio was there, no problem. The video and audio were completely rendered, so there was no way that audio track wasn’t missing.

          I then opened up the video on YouTube and thought I’d try to find when/where the audio went missing. But it was back–just like the original. CW and radio audio where it was supposed to be.

          So, I made the video public again and it was fine. I checked it a few more times.

          You’re the first person to mention the audio missing again, so I checked it on YouTube and it’s working fine for me. You might want to refresh the video or open it in a new browser window and try again.

          I can’t figure out why this is happening. 🙂


  3. This is interesting – I’ve noticed that YouTube doesn’t seem to like CW. Or is it the browser?

    My own videos play normally the first time I play them after an upload. After that, there is always a portion of the video where I either hear no CW where it should be or two instances of CW playing at once, ie the CW from the proper clip in the video and CW from something that should play 15-45 seconds later. The latter is the more common scenario.

    No one else has mentioned this to me, so it may be a problem with the data having been cached by my browser – and now it’s playing the cached audio in addition to the currently-streamed audio.

    I’ll bet this doesn’t happen to anyone the first time they watch a CW video.

    And it doesn’t happen with other (phone, SSB) audio – just CW. Weird, eh?

    1. It is very strange indeed.

      It seems to be dynamically re-evaluating what it should or should not mute too. Seems like every day it’s muting the CW in my audio for some length of time, then unmuting it.

      We CW folk may have to find another video platform. 🙂

  4. I think the CW may be in opposite phase in the left and right channels. Coming through earphones, I hear the CW audio clearly, but playing the audio through my phone’s single speaker, the two sides cancel out perfectly.

    1. I think Rob has figured it out. When I view the video on my laptop, the CW audio is there. When I view the video on my smartphone using the internal speaker, I hear no CW. When view video on my smartphone using stereo headphones, there CW is again audible.

      I don’t know if the issue is your digital recorder recording the CW as two out-of-phase channels, or if the problem occurs when you mix the the camera-mic audio with the radio audio.


  5. Hi Thomas,

    I tried it again today with my old Chromebook and had solid copy on the CW as well as your comments for the entire activation. I was using my Android phone with Chrome browser before when I couldn’t hear the CW. So if that happens again, I’ll switch to the Chromebook. One other difference: on the Chromebook today, I didn’t hear the birds. 🙁



  6. Thomas, I plan on riding my motorcycle to this park Sunday for an activation. I see picnic table number 19 but which trail was this table on? I got the MFJ 1984LP also and it does indeed need a little room to get up. Working on getting a 20m end fed soon. Thanks

    1. So I’m describing this from memory, but it’s on thhe far end of the loop opposite side of the stream from the picnic shelter. Actually, I believe I walk to it from the parking lot in my activation video! It’s in the first part of the video.

      1. If I had just watched the video I would have answered the question myself. You are correct, you actually film from the car to the picnic table. Thanks again for all you do Thomas.

  7. Hi Thomas.

    Do you know what the receiver tuning range is? So could you for instance tune the MW broadcast band, yes I accept it will be a lot less sensitive due to the front end band pass filters.

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