[TowerTalk] A Capacitively Fed 102 Degree Vertical for 160 Meters

[Doug Smith]

I use an inverted L for 160 with an old Heathkit SA2550 at the base of the
vertical element.  The 2550 is an electrically driven large variable
capacitor, remotely tuned/turned from the shack.  I use 4 elevated radials
and the base of the vertical is mounted on top of a 12’ piece of pressure
treated 2x4 buried in about 2’ of concrete (hence the top of the 2x4 and the
SA2550/base of the vertical element is about 10’ above ground, as are the
radials).  In this fashion, the radials are not tuned.  The vertical element
is tuned by varying the capacitance in the SA2550.  I can easily achieve SWR
of 1:1 over the whole 160m band in this fashion.

 

By the way, I use the same system for a ¼ wave 80 meter vertical with the
same results:  1:1 over the entire 75/80 meter band, varying only the
SA2550.

 

Now, here’s the hard part:  finding an SA-2550.

 

73, Doug W7ZZ