The big relay in the TL-922 is too slow, with or without a diode. On 9/3/2011 12:38 PM, Fred Townsend wrote: > Please see comments below. > > -----Original Message----- > From: [email protected] > [mailto:[email protected]] On Behalf Of Vic K2VCO > Sent: Saturday, September 03, 2011 11:51 AM > To: [email protected] > Subject: Re: [Elecraft] K3 with a Kenwood TL-922A > > Actually, I believe that the K3's amp keying output could handle the +120v > key line of the > 922 with no trouble. My TL922 came with a diode across the t/r relay, by the > way. > > BUT -- there is a much bigger problem with the TL-922. That is that the > relay is very, very slow. You would probably have to increase the TX Delay > of the K3 to prevent hot-switching, and increasing it beyond 12-15 ms messes > up your keying. Buffers and soft-keys CANNOT fix this problem. > > Vic: Do you realize that placing a diode across the T/R relay slows it down? > If you are going to quickly swing the relay you are better off to shunt the > key line with a transient absorbing device like a transorb. As the name > infers that's a zener that especially designed to absorb transients. That > will speed the decay of the relay field rather than delaying it. The type > transorb used must be selected to have a sustaining voltage greater than > normal key line voltage. You want the transorb to only conduct during the > transient period. > > 73 > de Fred, AE6QL >
-- Vic, K2VCO Fresno CA http://www.qsl.net/k2vco/ ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
