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Old 07-19-2007, 02:38 AM
Donald Newcomb
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Default Re: Aircard yagi antenna help needed

"szilagyic" <chris@groupinfo.com> wrote in message
news:1184776639.860365.204020@o11g2000prd.googlegr oups.com...
> ). It is attached to a 30 ft RG58U coax cable that runs back to a
> TNC-
> to-FME adapter, then to the Sierra card.


Here's your first problem. Assuming that you're using a 1900 MHz signal,
you'll only get about 10% of your signal at the end of 30' run of a stock
RG58 cable. There are some "super" RG58 cables (RG8X Ultra) that work much
better and are much more expensive. Normally, for this length of cable you'd
need a foam dielectric RG8.


>
> We tried the yagi at another location where we only get about 30%
> signal strength with the stock antenna. We do not know where the
> tower is at so we started in one spot and went in 5 degree increments
> in a complete circle, noting the signal strength at each stop. The
> highest we were able to get is about 20%.


The other thing you should keep in mind is that your phone won't necessarily
be looking for the strongest signal. The phone will lock onto the cell that
the system tells it to lock onto. In general, a Yagi works best in remote
places like an island where the cell towers you are "working" are all in the
same general direction. They will not work as well in places where the cells
are all around the antenna. No sooner do you get the antenna properly
pointed than the system decides that your phone should be talking to a
different cell.

--
Donald R. Newcomb
DRNewcomb (at) attglobal (dot) net



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