Isn't schedule 80 water pipe? And if so, aren't you inviting a bent
mast by trying to put a 2-element 40m yagi 10 or more feet above the
tower top?
73, Pete N4ZR
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On 1/26/2010 8:31 PM, Jon Casamajor wrote:
> 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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