Doug, I would not say that there is any 'magic' length for the feedline. Try what you can do and see what works. If it ends up that the tuner has difficulty matching the shack end on one or two bands, add some extra feedline and try again.
Depending on the matching range of your tuner, you may encounter difficulty tuning the combination if the feedline length plus half the flattop length come close to a half wavelength or multiple (those lengths result as a high impedance feedpoint). There are several programs that will tell you what the shack feedpoint impedance will be, and I recall that LB Cebik has the antenna feedpoint impedance for the 44 ft. doublet listed on his website www.cebik.com - look for an article titled something like - If I Could Only Have One Antenna. 73, Don W3FPR ----- Original Message ----- > I'm preparing to put a 44 foot doublet into my attic and I'm wondering > if there is a magic lead length that allows me to work 10 to 40 meters > with minimal Z on all/ most of the bands. I plan on using either 300 > ohm twin lead or 450 ohm lead to a tuner with a built in balan. Shack > is close to the middle of the house immediately below attic, so lead > could be less than 20 feet. How about 22 feet times velocity factor of > lead??? Any comments? > _______________________________________________ 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
