[Elecraft] K3 RFI in transmitted audio

[Jim Brown]

On Sat, 11 Sep 2010 13:37:49 +0000, Felipe Ceglia wrote:

>Here is the setup:

>rig A:
>K3
>heil proset on front panel
>pc audio on rear plugs
>cat plugged via microham microkeyer
>nothing plugged on cw key jack (that minimized rfi a bit, it was
>coming from microkeyer)
>JRC 1kw amp

>rig B
>ft2000
>cat cable to pc
>icom pw1 amp

>The antennas are all near the shack.

>When rig B TX, depending on band, it gets into K3 TX audio.

You still didn't tell us about DC power for these rigs and the other equipment. 
That can be VERY important for problems like these. Note W4TV's advice on this.

Based on limited information, I suspect a pin 1 problem in the computer, but 
I'm not ready to rule out the power supply, and strongly urge you to follow 
Joe's advice. If RF is getting into the computer, the solution is a multi-turn 
choke on the audio cable between PC and the K3, and another on the serial 
cable. I think you said 80M was the primary band. That will take a lot of 
turns. See my RFI tutorial. http://audiosystemsgroup.com/RFI-Ham.pdf 

So I repeat my question about power -- EXACTLY how are you powering each rig 
and each piece of equipment connected to these rigs? I don't know the FT2000. 
Does the FT2000 run on 14Vdc, or does it plug directly into mains power? 

73, Jim Brown K9YC


>2010/9/11 Jim Brown <jim at audiosystemsgroup.com>:
>> On Fri, 10 Sep 2010 21:35:49 -0300, Felipe Ceglia wrote:
>>
>>>When second rig is TX on 80m, I get the whole audio being coupled by the K3.
>>
>> Please give more detail about your problem. Are both radios transmitting at
>> the same time? Both K3s, or one a different radio? Is there a computer
>> feeding either radio?  Where do you hear the RFI?  Where do the radios get
>> their DC power?  Exactly. What kind of power supply? Is the V- terminal
>> bonded to the chassis at the power supply?
>>
>>>Is this a common issue?
>>