[Elecraft] Phantom signals

[Don Wilhelm]

Another thing to suspect is noise generated by a computer, or ethernet 
modems and routers and being routed to the K3 and P3 via the K3 to 
computer connection.  I believe that is why Tom suggested winding the 
USB cable through a type 31 ferrite core.  BTW, that core should be near 
the computer end).

Disconnect and power down the computer to see if that is contributing to 
the "spurs".

73,
Don W3FPR

On 11/27/2018 5:57 PM, ab2tc wrote:
> Hi,
> 
> Absolutely no sign of any of these spurs here with my K3S. Since they are at
> constant frequencies they must be coming in through the K3 front end (*not*
> at the IF level). So either your K3 front end is generating them (which it
> shouldn't) or they are present in your environment. Again, since they are at
> constant frequencies, the P3 or any other SDR connected to the K3 IF output
> should not be the culprit. Send me an E-mail and I will give you spectral
> plots collected with LP-PAN/NAP3 with K3 connected to a well shielded dummy
> load.
> 
> AB2TC
> 
> 
> tomb18 wrote
>> This is pretty common. One thing that can help is to wrap your USB cable
>> through an ft241 31 to rid. About 6 turns gets rig of lots of picked up
>> garbage. 73 Tom
>>
>>