Tom wrote: My shack is located in the basement, and the only way to get RF out is by a rather circuitous route through a couple of walls, so I don't think open wire line is possible. The antenna wire is then fed at the ground end. If I shorted braid-to-center at the rig and fed the whole thing as a wire I have a problem with where to put the counterpoise. I don't have room for radials attached to the case of the rig, and don't have direct access to earth-ground.
-------------------- Sounds like the way to go is to center fed a dipole with coax. Even if you have to fiddle around with the path of the coax so it runs parallel with the antenna for a while to get to the center, just keep it as far from the radiator as possible before running up to the center point of the radiator. Now, you must keep the SWR within reason. There's a couple of ways to do this that work pretty well and don't need to cost much, will provide you with coverage of at least 40/20/15 and 10, and, perhaps, some of the other bands in between as well. First, if you can get 66 feet of wire up there (even if the ends have to droop down or run off a an angle from the insulators for a bit to make the length) you are all set. That's a 1/2 wave on 40 and 3/2 waves on 15. That provides a decent match to minimize feeder losses on 40 and 15. Now you can connect in parallel with that dipole two more dipoles: one is 33 feet long and one 16 feet long. If you don't have other attachment points, just let them droop below the 66 foot dipole and, after the end insulators, tie them off to the 66 foot radiator. An easy way to do that is to use monofilament fishing line at the ends of each radiator. It's a great, lightweight insulator. The three antennas will interact somewhat, but the system will show a usably low SWR on 40,20,15 and 10 meters. Your ATU will probably load them up on the WARC bands as well, although the SWR may be fairly high there. Ron AC7AC _______________________________________________ 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
