Interesting Interference

Butch

This caught me off guard yesterday... I happened to key my VHF/UHF HT on 445.000 (on low power) near the TG-XL's display and an error message popped up on the TG-XL's screen saying, "NO PTT IN". I own two TG-XL's and they both do this. I heard the same thing happened to a ham friend in Florida with his TG-XL. Anyone else see this condition?

David Decoons, wo2x

Yes. the tuner is seeing reflected power (RF from the HT too close to tuner) and not seeing a key signal from radio (LAN or PTT RCA).

73

Dave wo2x

Butch

Dave my HT was set to approximately 100 milliwatts and caused this interference. Perhaps some filtering might be in order.

Mike-VA3MW

What Dave said is correct. Adding some chokes to the DC line and RF line to choke VHF and UHF frequencies will help solve this.

Butch

Thanks for your input Mike. I took your advice today but it didn't help. Same situation.

KD0RC

Hi Butch, if you can determine what path the RFI is coming in on, you will have a better shot at solving it. My trick is to start disconnecting things until the problem goes away. The last item removed is probably the path. The path may or may not be radio related; for example, an internet device like a printer.

In one case I had RF coming in on the key line. Unplugging it from the back of the radio immediately fixed the issue. Then I wrapped several turns of it in a ferrite bead and plugged it back in. Problem solved. In another case it turned out to be an unused switch connected to my network. The RF was coming in on the power cable. Same fix cured that one.

In a case like this it is possible that the RF is coming directly into the circuitry of the amp. Ferrites won't solve that one, but you need to go through the exercise to figure out where the problem lies.