Herb, you can feed any number of bands through one gamma arm or wire as long as the highest frequency to be used is less than 1/4 wave length on the gamma arm or wire. The appropriate matching is still required for each band. I fed my 70ft grounded tower for 160, 80 and 40 meters with a gamma of 27ft length...de gary
-----Original Message----- From: Topband [mailto:[email protected]] On Behalf Of Herbert Schonbohm Sent: Tuesday, February 25, 2014 11:52 AM To: [email protected] Subject: Re: Topband: In search of resonance On 1/30/2014 11:03 PM, Carl Braun wrote: > If I can't get the antenna to resonate using the L I'd say that I'd consider shunt feeding the tower and work out an (omega) matching scheme to match the tower to my target freq. If that's the case, do I mount my upper shunt arm on the tower at 67' or at 90'? > > Can I run a single drop wire into my panel and then switch the feed between two matching networks? One for 160 and one for 80? > > Please advise > > Thanks > > Carl AG6X > > > Carl, Why not just run a slant wire to your shack and feed the bottom against a ground system through an ATU. Don't expect any real drama on 80 meters as the tower is probably to long electrically. ut a slant on any frequency could be modeled to see what you choices are. The only way this could change if you made a decoupling sleeve on the tower so the radiator appear to be between 1/4 and 3/8 wave length. It can work as a duo bander but it will require some extra work and a good vacuum switch since the voltages may be high at the in/out switch point. Some directive in the direction of the slant may occur but it should be be slight. As far as a drop wire shunt is concerned: There should not be any advantage of having the drop wire shunt arm much higher than the approximated sweet point for you tower. Herb Schoenbohm, KV4FZ _________________ Topband Reflector Archives - http://www.contesting.com/_topband --- This email is free from viruses and malware because avast! Antivirus protection is active. http://www.avast.com _________________ Topband Reflector Archives - http://www.contesting.com/_topband
