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CHANGE USERNAME TO westes
July 6th 04, 09:03 PM
Will a wideband aviation antenna, that receives across 50 MHz up to over
1000 Mhz, be useful for VHF and UHF TV reception as well as aviation
frequency reception?

Can such an antenna be used by multiple devices listening to different
frequencies at the same time?

--
Will
westes AT earthbroadcast.com

July 7th 04, 12:32 AM
On Tue, 6 Jul 2004 13:03:36 -0700, "CHANGE USERNAME TO westes"
> wrote:

>Will a wideband aviation antenna, that receives across 50 MHz up to over
>1000 Mhz, be useful for VHF and UHF TV reception as well as aviation
>frequency reception?
>
>Can such an antenna be used by multiple devices listening to different
>frequencies at the same time?

Theoretically yes.

In practice these broadband antennas have poor gain (<0db) as it's a
compromise. Unless your signals on VHF and UHF are strong the result
will be poor.

If you split one antenna between two receivers then each will receive
only half the signal (-3db). In fact less due to splitter losses. The
only way to overcome this is to use a broadband amplifier (covering
VHF & UHF) and ideally close to the antenna to avoid cable losses.
This will boost the signal first so it can then be split.

A somewhat technical reply is:
A very rough guide to antenna performance is double the antenna
elements gives double the signal. A broadband antenna is likely to be
slightly poorer than a simple dipole. Using a dipole as a reference
you will get roughtly double (3db) more signal with two elements and
roughly double again (6db) with four elements. If you double yet again
to eight elements that's another 3db. Each element needs to be the
correct length for each band of frequencies.

If by chance the UHF frequencies are exactly three time the VHF
frequency then one antenna could be used but performance would not be
as good s two separate antennas.


David

E-mail (Remove Space after pilot): pilot

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