Wow, Incredible responses in just a few min. Thanks ! This antenna will be used 90% for Contesting, but 5 days a week it will be for casual DX on CW and SSB. With the switching matrix I'm using at the shack, it would be hard to use a tuner, and is what I'm trying to avoid. On my JK 801's the Motorized inductor, controlled by a Green Heron Controller using band data from N1MM makes it totally automatic (Flat SWR in ~ 50khz segments)
From my talk with Mike @ Tornado Tuner, the 160m version, that I believe was made for a short radiator is as follows... *"The Tornado 160SS will tune from about 17uH to 33uH. It has a single 27.5 turn coil. The coil is 1/4” diameter aluminum, and the coil is 4 3/8” mean diameter."* From the replies, I see that my approach of build it and figure out the tuning later was the wrong misguided. Please forgive my ignorance, I don't have the experience or background to understand what a lot of this means. It seems that IF I wanted to use the tornado tuner, I would need to figure out a way to model the antenna so that adding 17uH to 33uHof inductance would allow it to tune across or close to across the band ? And that them numbers may be way out because it was designed for s shorter element ? I want it Automated so I can put any poor soul I can convince to join a multi op in the seat and just turn them loose. Thanks again for all the great replies so far, *and Frank... Loved the presentation of the LPL history yesterday, Incredible. * Ron, WV4P *Grant, Going to read your Doc now, If it sends, I have attached a pic of the base I built. The other next to is is one of 3 I made for the 3 Rotating Towers I am putting up. * On Fri, 15 May 2020 at 10:34, Tree <[email protected]> wrote: > One approach for the inductor that I have used when doing parasitic element > tuning is to put two SO239's in series and either put a shorted plug in for > no added inductance - or a PL259 fashioned with a few turns of heavy gauge > wire. You can label them for the frequency you are wanting. > > I used that technique to go from a director to a reflector back when I was > playing with a vertical parasitic array on 160. > > Tree N6TR > > On Fri, May 15, 2020 at 8:28 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 > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
