[TowerTalk] Using Screwdriver Antenna as a Base Antenna

[Chuck Counselman]

At 1:50 PM -0700 6/21/03, K wrote:
>...been thinking about mounting another Screwdriver
>antenna on top of my 10x20 foot and 9 ft high metal
>top garage in the middle.  I was wondering how well it
>might work 80-10m without any other radials?


1. Make a short, fat, low-inductance connection between the shield of 
the coaxial feedline and the metal of the garage roof at the 
feedpoint of the antenna.  (Otherwise too much current will flow on 
the outside of your coax.  This happens in automobile/van/truck 
installations, too.)

2. Bond, electrically, well, all the seams of the metal of the garage 
roof.  (Otherwise, nonlinear conduction will generate harmonics and 
intermod products.)

3. Mainly for 80 m, and if your soil conductivity is good, maybe drop 
some fat conductors from the corners or edges of the roof to 8-ft. 
ground rods.


If you do #1 and #2, it should work very well.

-Chuck, W1HIS