I picked up a used TenTec Hercules amp in very good condition. It works fine from my Omni A and Omni V, but I'm thinking that I would also like to drive it with my K2. I've looked at the drive from the Omni A, and it appears that 10-15 watts will get me within a dB or so of rated power from the Hercules.
The Hercules was designed to work with the old Omni A, which generates a pre-delay keying signal (the call it the "T line") that is +12v on transmit, but transitions roughly 10 ms before the Omni transmits. (The Omni 5 also generates this signal, but doesn't take it outside the radio because later TenTec amps key differently.) The Hercules keying input drives the base of a 2N5087 through 1K, so it isn't going to draw much current. The doc on the K2/100 says that the 8R line is high on receive and 0v on transmit. An app note on the website says that this is a "pre-delay" keying signal that transitions roughly 15 ms before the K2 transmits. It looks like all I need is a simple inverter (NPN, collector to the amp keying line, emitter to chassis, K2 drives the base through 1K) from the 8R line to the Hercules keying line. Does this make sense? My rig also includes a KPA, but I don't think I need it. It has a key output to drive power amps, but there is no doc on it. Is it also a pre-delay signal (that is, 10-20 ms before transmit)? What is its logic -- positive to transmit? Jim Brown K9YC _______________________________________________ Elecraft mailing list Post to: [email protected] You must be a subscriber to post to the list. Subscriber Info (Addr. Change, sub, unsub etc.): http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/subscribers.htm Elecraft web page: http://www.elecraft.com
