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Posted by: Cal K4JSI Posted On: 09/02/02 Subject: Re: Multiband Wire Antenna - Looking for Comments Message Posted: In Reply to: Multiband Wire Antenna - Looking for Comments posted by Cal Cotner K4JSI on 08/22/02 Let me say thanks to KG8ZQ, OK1SIP, AG5P, W1PID and K5QLF for your comments on my thoughts about replacing the attic-mounted aluminum foil doublet! I do apologize for not having given a bit more detail about the layout of our yard, the house, the tower and our garage. But even without that, your comments have set me to thinking a bit more. AG5P suggested a radiator length of 100 feet, end fed through parallel lengths of coaxial cable. I assume that one center conductor would be connected to the radiator and one to the counterpoises he also recommended. That impelled me to look up WB8IMY's article in the October 1998 issue of QST, titled "One Stealthy Wire", in which he suggested 80 feet of wire, fed against radials. I fancy I could do this and might splurge on an automatic antenna tuner placed at the juncture of the radiator and the counterpoises or radials. Others suggested that a center-fed (with ladder line)135 foot radiator would be a good solution, with the refinement by W6RCA of "tuning" the feeder length to provide a low resistive impedance mentioned by at least one person. FWIW, to find his discussion of this, call up W5DXP on Google, or similar. The old W6RCA site seems to have vanished. A G5RV was also suggested. I imagine I could tune the feeder length in the manner worked out by W6RCA. I expect that the 88 foot doublet could be dealt with in the same way. With these approaches, I could do the feeder length adjustment in our garage and the low-impedance feedpoint would be close to the base of the tower that holds my VHF/UHF stack. The 136 foot off-center-fed approach was encouraged to an extent. I could purchase a "Carolina Windom", but might thresh around on my own with a 4:1 balun and see what came of it. Apparently no one knew of a manufacturer that sold an OCF with the two wires as described in the appended translation to the Belrose and Boulaine QST article. My thanks again to all of you. I hope QRP-ARCI will forgive this rather lengthy summary; perhaps someone will find it helprul. 72/73 Cal K4JSI QRP-ARCI #5693 G-QRP #3283 |
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