n2ic@druxm.UUCP (LondonSM) (04/04/84)
I have had considerable experience with rotatable 40 meter dipoles and
their interactions with tri-banders.
Yes, you are right on target with the idea of getting the 40 meter
dipole as high as possible. I have tried it both ways - with the
tribander on top, and with the 40 meter dipole on top.
There was a considerable improvement on 40 meters with the 40 meter
dipole on top. However, I should point out that I had 15 feet of
separation between the tribander and the dipole (the dipole was at
80 feet, and the tribander was at 65 feet).
You are also correct in being leary of interactions between the 40
meter dipole and the tribander. Even with 15 feet of separation,
I effectively killed the performance of the tribander on 15 meters.
(The performance on 20 meters also left something to be desired.)
The solution I have chosen is probably not universally applicable -
Separate towers for the tribander and the 40 meter antenna ( I am
replacing the rotatable dipole with a 3 element monster).
A better alternative may be to obtain the driven element from a
Wilson tribander, Mosley TA-33, or Cushcraft tribander.
All three of these antennas have the capability of adding an additional
trap for 40 meters. Use this driven element in place of your Hy-Gain
tribander driven element - or, better yet, sell your Hy-Gain tribander
and put up the Cushcraft quad-bander.
Let me (and the net) know how you make out.
Steve London , N2IC/0
druxm!n2ic