[Elecraft] [K3S] intermittent RF path interruption

[Bob McGraw]

Also check to see that SPLIT is not active on 6M

73

Bob, K4TAX


On 4/12/2020 3:03 PM, Nr4c wrote:
> Well first I’d try with a “dummy” load.
>
> The swap antenna to Ant 1.
>
> Sent from my iPhone
> ...nr4c. bill
>
>
>> On Apr 12, 2020, at 3:23 PM, Ben Gelb <ben.gelb at gmail.com> wrote:
>>
>> A bit of a mystery w/ my K3S and I could use help figuring out what the
>> problem might be.
>>
>> Background: I have had the radio parked on 6m for several weeks (HF antenna
>> temporarily out of commission) and have left it running (receive) for
>> extended periods.
>>
>> Recently, I have noticed that when I do sit down and try to operate, the
>> radio will get into a mode where during TX the rig will indicate 0W forward
>> power during transmit. Following this zero power TX, the RX will also go
>> quiet. Then seems to stay that way for some time (not clear to me what
>> makes it clear up... or if it ever does if left alone).
>>
>> Some experiments I have done to try to figure out what is wrong:
>> - Hitting the tune button also shows 0 power (instead of usual 10-15W) when
>> radio gets stuck in this state.
>> - Dialing the power down to where I hear the 100W PA switch out of line
>> (relay click... around 8.0W) seems to immediate restore receive and also
>> causes the rig to make power again on transmit. But when I turn it back
>> past 8.0W, it appears to go back right back into the bad state (so suggests
>> whatever the issue is, is in the 100W PA module).
>> - Switching to another band and transmitting momentarily (think I tried
>> 15m) will sometimes knock the radio out of this "bad" mode. But going back
>> to 6 meters will eventually cause it to happen again. Usually pretty
>> quickly (several seconds of TX).
>>
>> Some other notes:
>> - Antenna always measures 1.1:1 on the K3S display (when TX working
>> correctly). Also checked w/ RigExpert. I don't think the antenna is the
>> issue.
>> - All my observations have only really been on ANT2 port (nothing connected
>> to ANT1 presently).
>> - Haven't really exhaustively tried to test band dependence of the behavior
>> because I don't have an antenna on the other bands at the moment and not
>> wild about trying to transmit into a big mismatch. So although it appears
>> 6m related based on my observations, that might not be exactly
>> representative of whats going on.
>>
>> Posting here in case I've given enough clues for someone to suggest what
>> may be wrong or how to narrow down further.
>>
>> Thanks,
>> Ben N1VF
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