More on ant. stacking problem

price at price at
Mon Jan 31 13:08:51 EST 1994

I appreciate the large number of responses I've already gotten on this
subject.  So far the votes seem to be running in favor of mounting the
40-2CD and TH-7 booms at right angles to each other, except for the
following comment from Bruce, AA5B:

        "My experience has been that antennas of the all-grounded variety (like
        TH6 and TH7) need to be in line with the 40m beam.  That is to say, 
        pointed in the same direction.  Antennas that have elements insulated
        from the boom (like KT34XA and DX engineering antennas) need to be
        perpendicular to the 40m beam."

which contradicts the above.

Another particularly sobering comment from Jim, AD1C is:

    Jim, there are definite interaction problems between the 40-2CD and the WARC
    dipole.  My father W1JR found this (even before he worked for Cushcraft)
    with a 40-2CD and the A3WS tribander (you should have the same problem).
    The problem is the 40-2CD shortened elements resonate around 9 MHz, 1/2 of
    the 18 MHz of the WARC antenna.  He eventually had to take one antenna off
    the tower to use the other, and when he moved to NH, only put up the WARC
    tribander, and the 40 meter beam is still on the ground.

And finally, another person pointed out to me that the boom on the 40-2CD
is resonant on 15 meters! (argh)

In any case, several of you asked about the ant. spacing, an issue I forgot
to include in my original posting.

I have a 15 foot mast in my rotator, so about 12 feet of it sticks out
above the tower.  The 40-2CD is as close to the top as the brace allows. 
The WARC dipole is about 2 to 3 feet below the 40 boom, in parallel with
the 40-2CD elements.  The TH-7 is as close to the tower as we could get it,
so about 8 feet below the 40.  Again, all elements are parallel.

Keep those cards and letters coming, folks--Jim, K6ZH

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