The trick to passive repeaters:
The inside antenna that re-radiates the signal from the cell tower
will have 22dB path loss for the first wavelength of distance, and 6dB
for each doubling of distance past that. Ferinstance, say the
re-radiating antenna needs to be able to cover a distance of 30'.
That's 30 wavelengths (more or less) at 800MHz. So the loss from the
reradiating antenna is 22 (first foot)+6(second foot)+6(to 4')+6(to
8')+6(to 16')+6(to 32') or 52dB. If the outside signal is, say,
-80dBm (which would be ok), then inside you're -132dBm, or useless.

Gain on the "outside" antenna needs to make up at least the 52dB loss
in this scenario, or you're still worse off outside than in. You
won't find a 52dB antenna at 800MHz. Nor a 36 probably. Note that
the "usual" 4-5' panel antennas used at 800MHz are about 14dBi gain.

The situation isn't any better at 1900. Although you can get more
gain from the "outside" antenna, the 30' of coverage is more
wavelengths (nearly twice as many) for 6dB or so more free space loss.


On Sun, 4 Jan 2004 11:51:57 -0700, "Mark Atanovich"
wrote:

Howdy,
I would like to get rid of my land phone line. The only thing keeping me
from doing this is the relatively poor indoor reception on my cell phone
(outdoors is just fine). I can't justify spending $700 for a powered
repeater set-up, but since I get good outdoor reception, would it be
possible to couple a dual frequency (800 & 1900 MHz) high gain (36 dbi)
directional antenna directly to an indoor multi directional unit (both 50
Ohm impedance)? This would only cost a couple hundred bucks, but will it
work in theory? Any advice or
other suggestions would be greatly appreciated.

Mark