[Amps] Relays

[Vic K2VCO]

Gary Hinson wrote:
> Thanks all for the excellent advice and links on T/R relays and switching
> times.  A wealth of knowledge.
> 
> That fascinating thread has perhaps delayed the day when I either rig-up a
> test circuit to check why my TS850+LK550 eats Jennings relays, or "just
> spend another $30" as someone put it.  I must be on my 4th relay now (MTBF =
> 2-3 years) and noticed it sticking towards the end of WPX SSB this morning -
> hardly an onerous job for a QSK-rated linear I'd have thought. 

Deterioration of the receive contact is the way they have failed for me. 
I had one last about 2 years and another that is still going after 
possibly 7 years (the amp is in the hands of another operator now). I 
have heard -- but don't know -- that the Kilovac HC-1 version, which 
looks identical to the Jennings RJ1A and has identical ratings, is built 
differently and lasts longer.

With the TS850, you can get a little more 'headroom' against 
hot-switching by not using the built-in relay to control the vacuum 
relay, but by taking the +12v on TX line from the ACC socket and using 
it to control a transistor that operates the vacuum relay. It saves a 
little time and is quieter.
-- 
73,
Vic, K2VCO
Fresno CA
http://www.qsl.net/k2vco