Hello Julius > Ok, I want to build a balun. It should be able to > handle 200 Watts RF (safety factor built into this > number), 80 thru 30 Meters (160M would be nice) and be > efficient.
Well, I'm guessing here, but I think you'll need to use ferrite to keep the inductance reasonable. You also want to keep the B field low so it doesn't get hot or non linear. Let's shoot for 200 gauss peak. If you were running 200 watts into 50 ohms, you'd need 100 volts on the line, but that would be into a matched load. Into a doublet lets say we have a 10:1 VSWR, so we'll see 1000 volts at the balun. How many turns? Lets try 10. Frequency, 1.8 MHz. Using Fair-Rite's formula, we'll need 6.26 cm squared core area. If you use FT-100-43 I think you'd need to stack them up until you have a 1" diameter by 5" long tube. I might be way off though. 73, de Michael, AB9GV _______________________________________________ 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
