Trevor, It’s unclear to me what you’re looking for. One transistor and a 24V power supply can activate a vacuum relay, but are you trying to key up an amplifier with the relay, ground a receive antenna, implement a QSK circuit, or what? Do you want to sequence the relay to prevent hot-switching. What kind of delay time (e.g., 10 mS) is acceptable? If you specify your needs more completely, I’m sure people on the list can recommend solutions.
BTW, i don't care for “hot shot’ circuits that pulse relays with a momentary voltage spike to speed them up. They work okay on large open frame relays, but can damage small vacuum relays that have a much more fragile internal construction. In tests here, I found that they can also lead to excessive contact bounce, sometimes as many as 15 bounces. There are better solutions! 73, Jim w8zr Sent from my iPhone On Nov 15, 2017, at 2:01 AM, MR TREVOR DUNNE <ei2...@eircom.net> wrote: I'm still looking for a way to do this can't see anything on W8JI's site suitable and the fast relay link isn't what I'm after, Thanks Trevor EI2GLB ----- Original Message ----- From: MR TREVOR DUNNE <ei2...@eircom.net> To: 'topband List' <topband@contesting.com> Sent: Tue, 14 Nov 2017 19:51:18 -0000 (GMT) Subject: Topband: Vac relay keying Hi Guys Can someone point me in the direction of a circuit I can use to key a 26v vacuum relay using the tx out on my rig, I have a 24v PSU I just need to know how to switch on the feed to the relay as quick as possible when I TX, Thanks Trevor EI2GLB _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband _________________ Topband Reflector Archives - http://www.contesting.com/_topband