[Elecraft] KX3: Hi SWR on 20m & 30m after KX3-2M install

[Frank Krozel]

Brian,

Can’t help wondering if ESD or similar build-up occurred with low humidity in the winter.

Frank KG9H

On Jan 28, 2015, at 3:26 PM, Brian Waterworth <brian.waterworth at gmail.com> wrote:

> I had a similar situation with my KX3 just after the RTTY round-up at the
> beginning of January.  I also have the 2M module installed and experienced
> the same challenges with the inductors.  SWR values after 2M module install
> seemed to be ok on HF.  I actually can't recall if they were high as I
> didn't check.  But, the auto-tuner had no trouble achieving less than 1.5:1
> matches with a regular ATU cycle (not the aggressive cycle) into my G5RV
> shorty.  After the round-up, I couldn't achieve less than 3 on most bands
> (ATU assisted) and in some cases an SWR of 75:1!!  I tried measurements
> into two different dummy loads that I had around the shack.  I bypassed the
> ATU and measured on all bands.  I had high SWR on all HF bands into both
> dummy loads.
> 
> The sad ending to my tail is that I had to send the KX3 back to Elecraft
> for warranty repair.
> 
> The report back, from the Elecraft tech looking at my rig, was that 5 of
> the RF board's ICs were blown.  Probable cause: near field lightning strike
> or greater than 100+ watts of RF energy into the KX3.  It is winter where I
> am (snow, cold :-) and we don't get lightning at this time of year.  Also,
> I don't know how 100+ watts would have slipped into the KX3.  It isn't near
> any other RF source with that kind of power.
> 
> It is interesting, Ed, that you are reporting something similar to my
> situation.  I hope you resolve your problem without having to send your KX3
> back.
> 
> P.S.  I struck up a nice email conversation with the folks at Elecraft
> support and they guided me through some tests and asked for measurements.
> They too didn't want me to have to send the rig back.  But, the results of
> the SWR measurements told them that something bad was wrong and the KX3
> needed servicing.
> 
> regards,
> Brian
> VE3IBW
> 
> 
> 
> On Wed, Jan 28, 2015 at 1:59 PM, Ed Hamlin <we2h at earthlink.net> wrote:
> 
>> Hi
>> 
>> I just recently installed the 2M transverter in my KX-3. I’m now noticing
>> high (11 to 25) SWR readings on 20m and I wondered if this might be related
>> (I don’t recall such high readings before). I’m using an off-center fed
>> dipole that has worked quite well in the past. The KX3 autotuner worked so
>> well in the past, and I’ve seen it tune on relatively short random wires,
>> so inability to tune on a good antenna seems rather odd.
>> 
>> Part of the installation required displacing L40 and L43 on the main RF
>> board to make room for the SMA connector. It’s possible to break one of the
>> leads on the inductor while doing this. L40 (as I recall) felt pretty tight
>> and I may have inadvertently pushed it too hard.
>> 
>> What would be the symptoms of an open circuit on either of those
>> inductors? Other than high SWR on 20m and 30m, I haven’t seen any anomalous
>> behavior.
>> 
>> 73s
>> Ed
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