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Re: mashed antenna



W1BFN@aol.com writes:
> 
>  1. I see about 15 db loss when my 10 dbc yagi starts pointing at the tree
farm
>  which surrounds me. The highest point on the property is the tribander,
which
>  will peer over the trees in most directions. I can put the the potatotennas
up
>  about 3 to 4 feet over the tribander. Does that bother you in terms of
maybe
>  the beam affecting the pattern of the mashers?
  
Mike,
That should be plenty enough above the tribander to minimize any interference.
The top of mine are located at the same elevation as my roof top and I notice
some 2m "splatter" that gets into my downlink when the antenna is pointed
directly at/over the roof, but none when pointed out at the sky.  Wish I could
hide a tribander behind that roof :-(

>  2. Also thinking about running RS rg6a and a uhf coaxial tv preamp up at
the
>  440 antenna. Using a 75 ohm splitter before the preamp to maintain 75 ohms 
> to  the rg6a, and as a convenient wiring point to the phasing line. ???

That's an excellent idea if you already have one of those preamps.  They
generally aren't low-noise, but they have a lot of gain.  If you can mount the
preamp very close to the antenna feed, I wouldn't even worry about the feed
mismatch (go ahead and feed it with 50 Ohm cable, but run the RG-6 to the
shack).  The phasing line should connect only at the terminations of the
loops.  The phasing line goes from one loop to the other loop (thus providing
a 90 degree phase shift between the two loops).  The feedline then connects to
one of the loops.

Good luck and let us know how the UHF-TV preamp works out.  BTW, Home Depot
carries a really heavy-duty RG-6 quad-shield with UV-resistant jacket.

73, Jerry

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