[RFI] Mysterious K3 Symptoms - RFI? : Important addendum

[Pete Smith N4ZR]

Hi OM - you say "every time".  Do you mean that literally?  Does it 
happen without your having transmitted before it happens?  It sure is a 
mystery, as is the fact that mine cleared up completely with no clear 
connection to anything I did.  I'm inclined to think that I may have a 
bad cable or connector leaking RF into the rig

73, Pete N4ZR

On 3/14/2024 5:01 PM, Hisashi T Fujinaka wrote:
> I have similar problems but I was thinking it was hamlib because of the
> way it triggers for me.
>
> It happens running wsjtx on an M2 Macbook Pro and remoterig down to the
> radio in my basement. There's a K3/0 in my office -> remoterig -> K3 &
> KPA1500 in the basement. Almost every time I move my transmit frequency
> the RX gain goes down to almost nothing. Jiggling the AF gain brings it
> back to normal. It doesn't always happen immediately when changing bands
> but changing TX frequency in-band triggers it right away.
>
> On Wed, 13 Mar 2024, Pete Smith N4ZR wrote:
>
>> Operating in this morning's CWT, and saw a recurrence of strange 
>> RFI-like symptoms.  After transmitting, RX gain sometimes was 
>> severely reduced, but simply moving the K-3's AF gain a little would 
>> cause recovery to normal. Sometimes, this was accompanied by a HI 
>> CURR warning on the K3's display, often occurring several seconds 
>> after switching back to receive.
>>
>> My working theory has been RFI, but my station is pretty thoroughly 
>> fitted with toroids. Still, there seems to be a correlation between 
>> running my KPA-1500 at about 1100 watts and this set of symptoms, 
>> which I have not been able to trigger running 100 watts   To further 
>> confuse things, I just had another episode of this occurring *several 
>> minutes* after the last transmission.
>>
>> One culprit I can think of is a 100-foot Ethernet cable between my 
>> station and my FIOS router.  I have bought a shielded replacement but 
>> have not yet installed it.  After reading some of the recent 
>> commentary about so-called "shielded" cables, I'm wondering if this 
>> is worth doing.
>>
>> Any suggestions, either K-3-specific or more general, would be much 
>> appreciated.
>>
>> **ADDENDUM** - I just tested into my dummy load with the amp 
>> operational at 1100 watts, and triggered all the same symptoms.
>>
>>
>