[Elecraft] Cold K3

[Richard Fjeld]

Hi Bill,

It is a characteristic of transistors.  I have always been taught that they need to be biased down to about half their safe output to avoid thermal runaway. That was a long time ago. Things may have changed.


As they heat up, they increase their amplification, as they amplify, they heat up, and so on.  Cold temps works the opposite.


In the early days of solid state mobile rigs, and during Minnesota winters, we could turn on our rigs and get nothing but maybe a back-light on the dial.  After a few minutes, it would start to have sound coming out of the speaker, as the circuit and components warmed up.  It also affects the oscillators.


Dick, n0ce




________________________________
From: Elecraft <elecraft-bounces at mailman.qth.net> on behalf of Bill Frantz <frantz at pwpconsult.com>
Sent: Tuesday, October 4, 2016 12:14 AM
To: Elecraft at mailman.qth.net
Subject: [Elecraft] Cold K3

During the California QSO Party, the temperatures in our
operation tent dropped below freezing. Two of us felt that we
were not getting full power out of our K3s when the internal
temperatures were low. Given that we were using the K3 to
measure power output, low temperatures could be affecting the
measurement rather than the power.

After sending CQ for 5 or 10 minutes, the K3s warmed up and the
output power rose to normal. Too bad calling CQ didn't warm the
operators as well. HIHI

Since we were getting about 90% power with the internal
temperatures at zero C, it is not a major issue, but we are
curious. Has anyone else experienced this effect?

73 Bill AE6JV

-----------------------------------------------------------------------
Bill Frantz        | Concurrency is hard. 12 out  | Periwinkle
(408)356-8506      | 10 programmers get it wrong. | 16345
Englewood Ave
www.pwpconsult.com<http://www.pwpconsult.com> |                - Jeff Frantz | Los Gatos,
Periwinkle Computer Consulting - pwpconsult.com<http://www.pwpconsult.com/>
www.pwpconsult.com
Security Communications Quality Assurance Promoting Community Through Secure, Reliable Computing. Periwinkle is a husband and wife team with over ...



CA 95032

______________________________________________________________
Elecraft mailing list
Home: http://mailman.qth.net/mailman/listinfo/elecraft
Help: http://mailman.qth.net/mmfaq.htm
Post: mailto:Elecraft at mailman.qth.net

This list hosted by: http://www.qsl.net
Please help support this email list: http://www.qsl.net/donate.html
Message delivered to rpfjeld at outlook.com