[TowerTalk] Radio's/tunnels

[Michael Tope]

These kinds of signal benders are used in MMDS industry to extend
coverage. A large receiving antenna is typically placed on a tower facing
the signal source. This antenna feeds a amplifier which in turn feeds a
cross polarized transmit antenna which faces away from the signal
source. I guess the trick is to keep the transmit and receive antennas
isolated well enough that system doesn't oscillate.

In the case of your office building, you could substitute a small antenna
in each room for the leaky coax. Just make sure that your building is
shielded well enough that you system doesn't oscillate, and that you are
not re-radiating a bunch of noise and multipath distortion back into
the outside world where the rest of us are listening (remember you will
be radiating the thermal noise output of your pre-amp across its entire
bandwidth - police, fire, FM, 432 MHz EME, etc).

Mike, W4EF.................

----- Original Message -----
From: Mark . <n1lo@hotmail.com>
To: <towertalk@contesting.com>
Sent: Friday, May 05, 2000 8:04 AM
Subject: Re: [TowerTalk] Radio's/tunnels


>
> << Cheap coax with less than 100% shield coverage will do about the same
> thing for far less cost.  k7gco >>
>
> <chuckle> I was thinking the exact same thing. My office building is RF
> shielded by metal lath and metal roof. I have been wanting to build a
> wideband repeater for scanner and broadcast FM listeners and leaky coax
> sounds like a great idea.
> I have seen Tandy brand RG-8 where you can quite clearly see the white
> dielectric showing through the diamond-shaped gaps in the braid! Finally
it
> has found a use!
>
> --...MARK_N1LO...--
>
>
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