I have completed the Temperature Compensation Procedure for the KX3
on 6m. Initially, I tried using the 5th harmonic of my 10-MHz OCXO
since it is very accurate and stabile, but harmonic level was
inadequate to run the temp comp procedure, so I used my XG3,
instead. I did run it a long time to stabilize the signal and
constantly measured frequency on my counter. Drift of the XG3 was
less than 2-Hz over a couple hours of continuous running (ran off the
same 14vdc PS as the KX3).
Before running the temp comp, Drift of the KX3 was 54-Hz upward
running a test at 5w output on a sequence to duplicate conditions
running JT65: 50-seconds key-down/70-seconds Rx, and repeated ten
sequences (20-minutes total). Power was monitored on a Bird43 with
25w termination.
After temp comp was complete the worst drifting occurred in the first
ten seconds of the first sequence (+13 Hz). After that there was no
more than 10-Hz drift with the trend toward less drift as the test
proceeded. The last few sequences drift was +5 Hz. I monitored Osc.
Temp and PA temp with the KX3 display and Osc temp reached 54c at the
end of 20-minutes running; PA temp was also 54c. Osc. temp would
drop slightly during the 70-second Rx portion of the sequence. Temp
compensation seems to work well to reduce frequency drift in
transmit. Rx frequency is within 1-Hz if not transmitting.
I did feel the KX3 body during the temp comp procedure and it was
much warmer to touch once 52c was reached then the radio with heat
sink runs after 20-minutes of JT65 simulation. So I can say the heat
sink is making a difference protecting the final
transistors. Internal heat still rises significantly so one needs to
do the temp. comp. to reduce freq. drift.
details:
http://www.kl7uw.com/KX3.htm73, Ed - KL7UW
http://www.kl7uw.com "Kits made by KL7UW"
Dubus Mag business:
[hidden email]
______________________________________________________________
Elecraft mailing list
Home:
http://mailman.qth.net/mailman/listinfo/elecraftHelp:
http://mailman.qth.net/mmfaq.htmPost: mailto:
[hidden email]
This list hosted by:
http://www.qsl.netPlease help support this email list:
http://www.qsl.net/donate.htmlMessage delivered to
[hidden email]
Locked
