Lee, The impedance at the end of an open wire transmission line depends on the line length and the antenna, If you know the antenna feedpoint impedance and the transmission line length, a program like TLW (from ARRL) can predict the impedance that must be matched at the tuner.
In many cases, a 1:1 balun (or no balun at all) will serve better than a 4:1 balun. The impedance that has to be matched by the tuner will almost always be something quite different than the characteristic impedance of the transmission line. Feedpoint values ranging from only a few ohms to a few thousand are not unusual for a multiband antenna. Yes, you can use your 4:1 balun, but if you have trouble matching the antenna system on some bands, just take the balun out and feed the transmission line directly, one wire to the coax connector center and the other wire to the ground terminal. The transmission line will still be balanced as long as the antenna is being fed at its electrical center - the fact that the current at the ends of the antenna must be zero will assure that the feedline will be balanced. You may check out LB Cebik's info on multiband antennas too if you have doubts, he states it in a different manner than I do, but the end result is the same - you don't really need a balun in all cases and connecting directly to an unbalanced tuner will do no harm especially in a portable situation. 73, Don W3FPR > -----Original Message----- > > > Field Day is coming up and the K2 is going out. I > have the KAT100 as well...and I want to put up a 130 > foot dipole with that ladder line stuff. Hey, its > only for 24 hours. To use the KAT100, I have a 4:1 > balun (a 4KW job). Can I use that with the KAT100 and > the open line feeder? What are all you guys doing? > > Lee - K0WA > > > Common sense is in short supply - get some and use it - Lee Buller > _______________________________________________ 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
