New Penntek TR-35 firmware adds CW message memory keying

John (WA3RNC) has just announced a new firmware (V.0.24) upgrade for the Penntek TR-35 that will start shipping in all TR-35 orders starting Sunday April 23, 2022.

The new processor adds two new features:

  • The ability to record and playback two CW message memories
  • A function to toggle the display from black with blue characters to solid blue with black characters

Of course, the big upgrade–in my world–is the addition of CW message memory keying and I can confirm that it works very well. More on that below…

Obtaining the upgrade

As John (WA3RNC) states in his announcement:

The good news is that any TR-35 can be upgraded with a simple replacement of a properly programmed plug-in microprocessor, or with the reprogramming of the original microprocessor. No other hardware changes are required.

But…there is bad news. The availability of the Atmega328P-PU microprocessor has gone from “buy it anywhere for $1.95″ in mid-2021″ to “virtually unavailable anywhere at any price” today. Delivery dates are quoted as May of 2023 for orders that I placed last year. 

[…]Because of this critical chip shortage, I do not have a sufficient inventory of the Atmega part to be able to send out programmed microprocessors for upgrades. What parts I do have are destined for production of TR-35 and TR-45L transceivers.

Therefore, a TR-35 firmware upgrade will require that the transceiver be sent to me freight prepaid for reprogramming, along with funds for return shipping and insurance of $15.00.

Understand that there is no charge for the actual upgrade reprogramming, only for the cost of returning your unit to you.

I think is excellent customer service, actually, and a clever way to get around the chip shortage: use the chip you already have.

Again, if you’re buying a new TR-35, it’ll ship with the latest firmware.

If CW message memory keying or inverting the OLED screen colors aren’t important to you, it’s not necessarily worth upgrading because the new firmware only includes the new features.

Testing message memories

Recently, John sent me an upgraded chip with an early Beta version of the new firmware to thoroughly test in the field. I replaced the TR-35 chip myself.

I tested the new functionality in the shack and on a dummy load.

As with most built-in CW message recorders, you’ll need to set the CW speed to a comfortable setting before recording. During the recording process, you need to send accurately spaced characters, else, for example, the software might interpret the “AN” in your callsign as a “P.”

The first time I set memory 1 to “CQ POTA DE K4SWL” it took three tries to get it right. When I set the second memory to “BK TU 73 DE K4SWL” I recorded it in one go.

Recording message memories on the TR-35 is at least as easy as directly recording a message on my KX2 or KX3. I’m pleased.

In the field

Last week, I took the upgraded TR-35 to the field and used the message memory keying during my activation.

It worked beautifully.

John sorted out a clever way to initiate playback without having to make any hardware additions to the radio:

  • To play a message memory, simply tap the AUX switch down and then hit the left side of your paddle to send message #1 or the right side to send message #2.
  • Recording messages works the same way, but instead of a short press of the AUX switch, you initiate a long press.

Even this early version of the upgrade worked well.

Field report and video coming soon!

I’m going to push the field report from last week to the front of the line because I know many of you will be curious to see how it plays in the field. Hopefully, I can post this by Monday (April 25).

My Penntek TR-35 Review

FYI: My full review of the TR-35 will be in the May 2022 issue of The Spectrum Monitor magazine.

9 thoughts on “New Penntek TR-35 firmware adds CW message memory keying”

  1. Any indication as to whether similar functionality will be added to the TR-25, or whether John would be amenable to letting someone reflash the processor themselves?

  2. This is such great news! Message keying was maybe my only real disappointment in the rig. I built it last month and have really enjoyed it.

  3. This rig just keeps getting better. I’m beginning to understand the “you get what you pay for” angle here; John’s kit costs significantly more than comparable others, but my exhaustive research suggests it’s also a significantly better product.

    I’m not in a position to build a kit yet, but expect to be in a few months. And I’m pretty sure it’s going to be this one.


  4. Hello Thomas – yes, it is unfortunate about the chip shortage. You’re right about the need to get the input timing absolutely correct for proper interpretation and playback. The final X in my callsign was seen as DT – like you, three tries later and all is well. This is reminiscent of the TiCK and many other keyers built into rigs and highlights our own imperfections of sending code. But get it right once (for programming) and it will be played back correctly.

    I did a POTA activation yesterday using the keyer and am happy to have that functionality but I will be getting the update which, according to John WA3RNC, has the word spacing shortened just a bit from that seen (heard) in my video.

    An excellent radio has become even better – too bad the global situation continues to make things more difficult than they should be.

    John AE5X

    1. I enjoyed reading your report and watching your video, John! I hope you keep producing these.

      Yes, I agree with your assessment about the spacing between words–this was most evident when I went back through the video of my activation. It’s just *slightly* long. I, too, will send this chip to be upgraded with the tighter spacing in the production update.

      It is a superb little radio and with message memory keying is now a solid field rig. One I’m sure I’ll end up buying.


  5. Awesome to hear. John had mentioned this was in the works when I got my TR-35, and I will gladly pay the shipping each way to have that update done. Great little rig with or without messages, but well worth adding.

  6. This sounds like a nice upgrade, and I do appreciate his willingness to upgrade existing units. But tinkering with microcontrollers is well within the abilities of many hams…hopefully he publishes a how to and releases the new code for download.

  7. Thomas, Thank you for the review and the videos of your POTA activations with this radio. After seeing your videos, and from the recommendation of a friend, I purchased the kit. Due to other obligations, it has been sitting around the house for a couple of months. I finally built it yesterday. It was definitely a fun build. The organization of the parts and the detailed instructions were definitely a 599. Best of all, it fired right up, and I was able to make a 13 Colonies contact. I can’t wait to take it out on a POTA activation. Thanks again… John (AF8E)

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