I would favor using an inductor. Tune it for the lowest part of the band. Then using a relay or two, you can short out turns if you want to move higher in the band. Although I think you will find using Rohn 25, it will be pretty broad.
73 Ken K4ZW On Fri, May 15, 2020 at 11:28 AM <[email protected]> wrote: > > > Hi Ron, > > > > A more reliable approach is a tuner in your shack. The extra coax > cable loss from elevated VSWR is insignificant on topband. > > > How high up the band do you want to go and at what maximum VSWR? > > > A resonant Rohn 25 160M vertical will be about 124 feet tall for > resonance around 1820 kHz > > If for some reason you must install a tuner at the feed point of the > vertical, follow Tree's advice and make it slightly short: 120 feet > of 115 ft if you need to tune for minimum VSWR above 1900 kHz. > > > > Use a small tapped inductor to tune it around the band. > > > 73 > Frank > W3LPL > > > > > > ----- Original Message ----- > > From: "Tree" <[email protected]> > To: "Ron WV4P" <[email protected]> > Cc: "160" <[email protected]> > Sent: Friday, May 15, 2020 3:18:39 PM > Subject: Re: Topband: 160m Vertical > > Slightly shorter makes it easy to use an inductor to make up the > difference. If you make it long - you can do the same with a capacitor - > but it's typically more trouble than the inductor. > > Tree N6TR > > On Fri, May 15, 2020 at 8:15 AM Ron WV4P <[email protected]> wrote: > > > I have built an insulated base for a 1/4 wave 160 antenna. The antenna > > will be XXX' of Rohn 25. In searching I see people using heights from 115' > > - 130' with a pretty high number around 124'. > > I do not know how I am going to match it yet, I figure I will do my > > research on that once it's up so I can learn while experimenting.... But > > the height has me second guessing. I want it tunable across the band, > > perhaps using a Tornado Tuner like my JK 801's have with a motorized > > inductor ? But the question at hand is do I want the antenna Tall or Short > > ? What is the Method behind the Madness ? :o) > > > > Thanks in advance, > > Ron WV4P > > _________________ > > Searchable Archives: http://www.contesting.com/_topband - Topband > > Reflector > > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband Reflector _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
