Tom Skinner wrote: I've been kinda lurking for a while and haven't seen much about power supplies.
Is there a 'supply of choice' for the K2? It's needs are modest, and present no difficulty, but for the 100 watt overshoes - well, that might be a different story. The following is my experience with power supplies. I was using an Astron 12A (9 A continuous, 12 A ICS) power supply for my K2 and KTA100, and an Astron 20A (16 A continuous and 20 A ICS) for my KPA 100. The KPA100 and KAT100 are in a separate EC2 case. Both power supplies are under my desk, so the transformers magnetic field will not mess up the K2. I had them set up so I could go QRP by only turning on the Astron 12A for the K2 and KAT100 from the top of my desk and then if I wanted QRO I would turn on the Astron 20A. The above worked great till I started to work 80 CW and got complaints of a rough CW signal whether or not I had the KPA 100 on or off. In other words, if I was running the K2 with the Astron 12A I got rf into the power line to the K2, (note this was also with the K2 into a good 50 ohm dummy load and with power down as low as 5 watts) I tried another power supply for the K2 and found the problem was in the Astron 12A. The solution was to use a Tripp Lite PR10B (7.5 A continuous, 10 A ICS) for the K2 and KAT100. This cured the rf problem on 80 meters. For general interest, I do not have an amp meter to measure the power supply current for the KPA100, but I did measure the voltage drop at the Astron 20A output terminals when it is driving the KPA100 at 100 watts. The volt drop was 50 mV, from 13.78 volts to 13.73 volts, in other words insignificant. This was on all bands 160 to 10 meters (except 60 meters, do not have that mod) and verifying my rf output power at 100 W using a scope. The power drop at the terminals of the Tripp Lite which is used for the K2 and KAT100 was less then 20 mV with the K2 putting out 10 W, again verifying my output power using a scope. I am not into portable operation, so it is setup permanently with switches (Computer AC power distribution panel that fits under my monitor) and power supplies under my desk. I just turn on the main switch and the K2 switch and I am QRP with the K2 and KAT100, by powering up the Tripp Lite power supply,and if I go QRO with the KPA100 turn on the switch for the Astron 20A. 72, Steve Ray K4JPN ex K1VKW EM82ep Warner Robins GA Elecraft K2 1422 & KPA-100 Heath Fan HW-101, HW-8 http://www.thewinstonator.com/k4jpn.htm _______________________________________________ Elecraft mailing list Post to: Elecraft@mailman.qth.net 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
