Interferance when transmitting

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Interferance when transmitting


I now have cqrlog talking nicely with my rig. But the rig may be talking too much back! When I transmit (particularly cw) I get garbage being filled into the call box on cqrlog (if the curser is on that box). I have noticed that this is true for any box that the curser happens to be on at the time of the transmission. Only noticed it on the 17m band. Is this cause for a bug report or is it interference from the rig?

Re: Interferance when transmitting

G'day Grant, long time

I have had the same problem before, it is not related to a bug in the software, it is RF in the shack that is getting into one (or more) of the cables that go to your computer. I know you work QRP but it can still get in.

You need to ensure that you have a good RF ground and also that your antenna is working correctly, by that I mean checking coax and cable connections everywhere, no exposed braid and good solder joints etc...

Open wire line can give the same problem, particularly if you are using it to feed a non resonant antenna (i.e. multiband) sometimes the line can have high standing waves on it, and this can lead to increased RF in the shack. My Balanced line fed Double Extended Zepp was what gave me grief particularly on 20m.

Adam VK4IM

Interferance when transmitting

Hi Adam.

Nice to hear from you, and good advice as always. Yes, I think you are right. I am using a G5RV, so the twin lead may be a contributing factor. I really should think about another antenna now after all these years. I have repositioned the computer relative to the transmitter and jumble of wires behind the operating desk and will see if that makes a difference.

Hi, first, it is more


first, it is more effective to reduce the source of the noise. Therefore you should optimize your setup as good as possible.
After optimizing, you could also have problems with some equipment, so you have to use an ferried bead with two or three windings on it. It is very important, that the coil is as near as possible on the plug to the computer.


Just add a ferrite

Just add a ferrite bead on the rs-232 cable, and if you have any extra cable between the two, coil it up so it will act like a choke as well.

Innterference when transmitting

I wound the cable from the transmitter to the computer around a ferrite rod and no more interference. Doesnt look too pretty but boy does it work!

Thanks for the tip.