I've built a lot of HF relay-switched projects, including a relay-based QSK switch for my ALS-600 amplifier. I've found that virtually any relay works well at HF as long as the contact rating and voltage breakdown are sufficient.
Since Power = I-squared R, at 100 watts and 50 ohms, you will have 1.414 amps RMS of RF current. And since Power = V-squared/R, at 100 watts you are looking at 70.7Vrms contact-to-contact voltage breakdown. Multiply these values by the square root of SWR if the relay will be used in a system with an SWR greater than 1:1 (worst case value). My favorite relays are the high speed OMRON signal relays available from Mouser (653-G6A-274P40-DC12), or Panasonic DS2E-M-DC12V relays available from Allied (788-1053). These are DPDT relays with contacts rated at 3-amps and 1000Vrms breakdown. These relays switch in 3-5ms typical, which is about as fast as vacuum relays. I paralleled the DPDT contacts to give a 6-amp rating for my ALS-600 QSK switch. These relays only cost about $3 each and plug into a 16-pin IC socket. Phil - AD5X _______________________________________________ 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
