Granted. The point is where time is involved do not suppress the transient by placing a diode across the relay coil. That doesn't necessarily solve the problem. You may need to bypass slow mechanical devices with fast electronic devices like optical isolators for break-in operation. 73 Fred, AE6QL
-----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Joe Subich, W4TV Sent: Saturday, September 03, 2011 1:18 PM To: [email protected] Subject: Re: [Elecraft] K3 with a Kenwood TL-922A > Vic: Do you realize that placing a diode across the T/R relay slows > it down? The diode only slows down the release ... the problem is the make time not the release time. 73, ... Joe, W4TV On 9/3/2011 3:38 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 > > ______________________________________________________________ > 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 > ______________________________________________________________ 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 ______________________________________________________________ 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
