Hi Rick,
You wrote:
I have a TH6 right at the top of my tower and a Cushcraft A3WS about 9 feet
above that. I have a serious tower and rotator and am going to add a 2
element 40 meter yagi this Fall. Can someone give me an idea of spacing
requirements between the three antennas? I have a 20 foot mast, 10 feet of
which is currently inside the tower. I plan to move up the rotator shelf.
Right now the mast only sticks up 10 feet. It's 1/4 wall Schedule 80. I'd
rather not side mount the A3WS lower down the tower as a local suggested.
Thanks for any guidance. Rick VE9HF
You don't have much mast to work with Rick. For 15 years I had a KT34-XA
mounted just above the thrust bearing and 10 feet above that and 90 deg out
of phase with the XA I had a 402-CD which was at about 90 feet AGL. That
combo worked super and having 2 el on 40 was a lot of fun and helped get me
5BDXCC.
I guess my real question is how high are you going to be able to put the 2
el 40? If you can get it up to 80' or so, it will start to play pretty well
probably assuming you can get some separation from the TH6 but your
available mast will make that a challenge probably. My gut feeling is that
with only 10' of mast or so to work with you won't be able to get either
antenna to work very well. You need more mast IMO.
I still have the 402-CD up 10' above SteppIR but have some VHF/UHF below and
above the 402-CD and it still kicks butt. I am taking it down this spring to
make more room for some additional VHF stuff. I run the 402-CD in phase with
the SteppIR with no problems but, and it's a big but, I can tune out a lot
of the interaction with the SteppIR on 15m. It's awfully nice to be able
to point the whole stack in the proper direction.
There is a picture of my current stack on QRZ. Buy some more mast, assuming
your tower can handle it and you will be happier with more separation than
you are planning.
73, Jon
K6EL
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