Best to use a 3 or 4 wire cage feed and you will find the match easier. You should tap the tower at 50 feet and work down till you find the sweet spot. A 500 to 750 vac variable will take care of any measure inductive component.
Herb, KV4FZ On Tue, Oct 15, 2019 at 3:10 PM Marty Ray <dx...@comcast.net> wrote: > I am shunt feeding a 70 ft Trylon tower with a Tennadyne T12.10-30HD LPDA > at 70 ft and a full size 40m rotatable dipole at 79 ft, (the top of the > mast is ~85 ft). Both antennas have relays that electrically bond them to > the tower when the shunt feed is in use. > > I have tried two shunt tap points, one at 65 feet and another at 45 feet. > Using a Rig Expert AA-55 Zoom, the Rs measured a little over 100 ohms on > the 65 foot version and 49 ohms on the 45 foot version. In both cases, > adding the shunt capacitor caused Rs to drop by approximately 50 percent, > (to around 60 ohms and 23 ohms respectively). > > I expected Rs to not change much, if any. I tried a vacuum variable, an > air variable and a silver mica. Same result. > > Has anyone seen this happen before? > > Regards, > Marty N9SE > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector