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

On Jul 18, 10:38 pm, "Donald Newcomb" <DRNewc...@NOT.attglobal.net>
wrote:
> "szilagyic" <ch...@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

Thanks for the reply. I did not realize that the RG-58 has that much
loss. I have also read that LMR-400 would be a good alternative. I
will do some more looking and replace the RG-58 and see how that
works.

Thanks much,
--
Chris

> Thanks for the reply. I did not realize that the RG-58 has that much
> loss. I have also read that LMR-400 would be a good alternative. I
> will do some more looking and replace the RG-58 and see how that
> works.

And use as little of it as possible. You lose more as the cable length
increases. Your best bet may be to use a PCMCIA capable router placed in a
weatherproof enclosure as close as possible the antenna. You can then run
ethernet CAT5 wire up to 300' from there.