[Elecraft] Sudden K3 AGC pop-off after adding P3

[Dan Sherwood]

Joe,

That's certainly a plausible explanation.  We ran MM logger all last weekend
during the CQP without problems, (P3 not built yet).  I had no issue with
HRD earlier yesterday, until later at night when I switched to 40 and 80
meters looking for few signals through heavy static crashes.  With all the
AGC pumping going on is when I had these problems.  Have the K3/P3 running
all morning w/o HRD.  No problems.

I'm looking at the LP bridge website now.  Thanks for the suggestion.

73,

Dan
WA6PZK



On 10/8/11 6:29 AM, "Joe Subich, W4TV" <lists at subich.com> wrote:

> 
>> At the time, the P3 was also connected to a PC running HRD v5.0. No
>> specific commands issued to HRD at the times of the AGC pop-off. I
>> was not transmitting at the time it occurred either, (RF not an
>> issue).
> 
> As indicated by others, this is an issue with overpolling by HRD.  HRD
> enables the *K2* extended response mode and then polls for AGC status
> *three times in succession* with no lag between the response to one
> poll and the next poll regardless of the "Refresh Interval" set in the
> HRD Options.
> 
> It appears that the slight delay in data through the P3 and the poor
> programming in HRD combine, perhaps with noise, to generate a false
> "AGC OFF" command.  One known "work around" (although with side effects
> of its own) is to use LP-Bridge as a buffer between HRD and the K3.
> LP-Bridge answers many of HRDs polls from its own cache and reduces
> the excessive of the K3/P3.
> 
> Note - "GT;" is not the only "duplicated" poll issued by HRD.  In
> addition to polling for AGC three times, HRD polls for both VFOs
> (FA;/FB;) twice, selected transmit VFO (FT;) twice, Bandwidth (FW;)
> *five* times,  Antenna selection (AN;) twice, and Power level (PC;)
> twice!
> 
> 73,
> 
>     ... Joe, W4TV
> 
> 
> On 10/8/2011 4:51 AM, Dan Sherwood wrote:
>> All,
>> 
>> After building and installing a new P3 pan adapter on a relatively new K3, I
>> notice the AGC fast or slow setting would suddenly shut off, accompanied by
>> a loud, distorted blast of signal audio.  Normal AGC function is
>> re-established by holding the AGC button, then tapping to select fast or
>> slow.  That would happen after a random period of time after power up and
>> sitting on a frequency, (several minutes to an hour).
>> 
>> I did not notice this issue before the P3 was plugged into the rig.  I¹ve
>> run the K3 over a week, including through the CQP contest and never noticed
>> this issue before.  Not sure if this is a software glitch or what.  With a
>> Heil Pro Set on, it is painful since it is unexpected, resulting in my
>> rapidly and forcibly removing the Heil Pro Set from my head!
>> 
>> At the time, the P3 was also connected to a PC running HRD v5.0.  No
>> specific commands issued to HRD at the times of the AGC pop-off.  I was not
>> transmitting at the time it occurred either, (RF not an issue).
>> 
>> I have the P3 right up against the right side of the K3 with only a few mm
>> separation afforded by the rubber feet on the K3.  I notice the K3 case is
>> hotter there, as the voltage regulators are attached internally to the case.
>> Should I allow some space for cooling there?
>> 
>> Any ideas?
>> 
>> 73,
>> 
>> Dan Sherwood
>> WA6PZK
>> 
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