[Elecraft] 12 meter K3 RFI from nearby FM station

[Vic Rosenthal 4X6GP/K2VCO]

I doubt that it is being picked up directly on the boards of the K3. I 
would try ferrite on the power leads as well as a line filter on the AC 
line to the power supply. Have you tried listening with battery power?

73,
Vic, 4X6GP/K2VCO
Rehovot, Israel
http://www.qsl.net/k2vco/

On 11 Feb 2016 20:55, Jon Zaimes wrote:
> Yes, that is the case. Hearing it on both of my K3 transceivers with only
> the 12v power cable connected, nothing else (listening on speaker).
>
> Thanks to all for the tips. Still absorbing the advice before proceeding.
>
> 73/Jon AA1K
> Felton, Delaware
> www.aa1k.us
>
> -----Original Message-----
> From: Elecraft [mailto:elecraft-bounces at mailman.qth.net] On Behalf Of Alan
> Sent: Thursday, February 11, 2016 12:04 PM
> To: elecraft at mailman.qth.net
> Subject: Re: [Elecraft] 12 meter K3 RFI from nearby FM station
>
> On 02/10/2016 03:57 PM, Jim Brown wrote:
>> Yes, this hit me between the eyes as well. The K3 has Pin One Problems
>> at many (most?) connectors, so RF current flowing on shields of cables
>> plugged into those connectors will couple into the K3. I've been
>> preaching to Wayne about Pin One Problems since 2004, when we met in
>> Dayton.
>>
>> If the problem is around 90 MHz, I'd use multiple one-turn and two
>> turn chokes with #43 material on every cable except the SO239 output,
>> which IS actually bonded to the chassis. Also choke the power cable.
>
> But it sounds like he was still getting the problem with no cables connected
> to the K3:
>
> On 02/10/2016 06:58 AM, Jon Zaimes wrote:
> ...
>   > Even when ALL cables are removed (only the power lead connected).
>   > Grounding or ungrounding made no change. I tried the radios on a  >
> battery but still had the RFI. Tried some ferrites on the power  > lead but
> no change.
>
> I suppose it could be a "pin 1" problem on the power leads.  It's kind of
> hard to avoid that with an Anderson PowerPole connector.  Probably
> additional low-pass filtering on the DC input would help.
>
> Alan N1AL
>
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