[Elecraft] K3 Chirp

[Dana Roode K6NR]

It was reported today by several folks who heard my CW signal that I have a
bad chirp - I was operating on 20 meters during CWT.  I listened to the
signal myself (my station is 80 miles away and I can listen on a local
transceiver).  Someone also sent me a recording.

I've been using the same K3, KPA1500, and Astron power supply for many
years.  I shut off the amp and could still hear the chirp.

One thought is that it has something to do with my power supply, although I
saw a previous posting that made that seem unlikely (below).  Wayne
mentioned something about KSYSN3 calibration, I had not heard of that
before, I will look into it.

If anyone has experienced a problem with chirp on a K3, let me know (it is
a K3 not a K3S).

  Dana



In reply to this post
<http://elecraft.365791.n2.nabble.com/K3-past-chirp-report-tp7625892p7625898.html>
by Doug Smith [W7KF]
Under normal circumstances, it is impossible for a K3 or K3S for exhibit
"chirp." The synthesizer settles well before the rig switches from TX to RX
or vice-versa.

The KSYN3A (newer synth, used in the K3S) settles in well under 1 ms thanks
to its entirely digital architecture (UHF DSPLL, divided down).

The KSYN3 (older synth, used on the K3) uses a more traditional PLL with
its VCO running at the target output frequency. It normally settles in
under 5 ms. It can take a bit longer depending on the actual PLL voltage
and VCO frequency. This is accounted for in firmware.

If your KSYN3 were not properly calibrated, you might see a longer settling
time on one or two bands, most likely 6 meters. If you suspect this, refer
to the CONFIG:VCO MD menu entry. The K3 includes an automatic VCO
calibration routine that requires no test equipment and takes only a couple
of minutes to run.

Wayne
N6KR



On Jan 19, 2017, at 12:57 PM, "Ron D'Eau Claire" <[hidden email]
<http://elecraft.365791.n2.nabble.com/user/SendEmail.jtp?type=node&node=7625904&i=0>>
wrote:

> In a synthesized VFO rig like the K3S, any tendency to "chirp" is almost
always related to the synthesizer momentarily losing frequency (or phase)
lock.
>
> While that could conceivably be linked to change in the power bus
voltage, it's highly unlikely since the bus is isolated from the actual
synthesizer by voltage regulators and filters.
>
> OTOH, the OO's report was strictly advisory. I have experienced spurious
OO reports over my >50 years of pounding brass, and one that turned out to
be accurate when I blew the filter caps in the transmitter and did not
notice, nor did the stations I was working report the hum on my signal.
When I got a "chirp" report one time (on a homebrew rig) and was unable to
hear it myself, I sent a friendly letter to the OO. He replied that he was
"almost sure" he could detect a "slight chirp" so he sent the card.
>
> So my advice is that if you can't repeat what the OO observed, don't
worry about it.
>
> 73, Ron AC7AC