Need help with TR-35

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KL7MJ
Posts: 97
Joined: Mon May 15, 2023 9:06 pm

Need help with TR-35

Post by KL7MJ »

I just finished building my TR-35 and have been testing it out as best I can with the bands. I have two issues that I'm concerned about.

1. The receiver motorboats on 40 and 30m, but is quiet on 20 and 17m. The motorboating subsides when I turn the VFO but immediately resumes when I stop.

2. The radio changed into RIT mode while i was tuning, and also changed bands and went into memory select mode. It does not appear to do this when I am not tuning the VFO.

Any ideas on what could be causing this? I'm hoping to actually get on the air with this rig as soon as the solar activity dies down.

Thanks.

Mike, KL7MJ
w0rw
Posts: 39
Joined: Wed Nov 16, 2022 5:27 pm

Re: Need help with TR-35

Post by w0rw »

Hi Mike,
Sounds like you have lost a decoupling capacitor.
Check all bypass capacitors on your +12V/+6V power line.
Look for missing or reversed capacitors.
Maybe you have a high impedance power supply.
Power the radio with a heavy duty battery.
Paul w0rw
KL7MJ
Posts: 97
Joined: Mon May 15, 2023 9:06 pm

Re: Need help with TR-35

Post by KL7MJ »

I wrote to John, WA3RNC to ask him about it. He said he'd prefer to look at himself. Long story short, he said the issue was that my Talencell battery pack has a noisy internal voltage converter that caused the noise. I was very impressed that John looked over my radio and had it back to me in about a week.

I only had a few minutes to try it out yesterday, but it is a very nice sounding radio!
KL7MJ
Posts: 97
Joined: Mon May 15, 2023 9:06 pm

Re: Need help with TR-35

Post by KL7MJ »

I think I've got it figured out!
The issue wasn't the Talencell battery pack, but rather the buck converter that I added to the power cord.
When I replaced it with a plain cable the noise stopped on 40 and 30. Also, replacing the cable improved the sidetone in my QMX (it was very raspy, which I misinterpreted as RF on the feedline getting into the radio).
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