Hi, I'd like to extend the operable range of a Radio Shack cat #
63-1110 mailbox alert. It works with a small photo sensitive
transmitter mounted inside the mailbox. When the mailbox is opened
(i.e. a change of light level) the transmitter sends a burst (of what
frequency I know not) to the base unit. The indoor wall-wart-powered
base unit with a 11" antenna flashes an LED and beeps when it receives
this signal.

The directions say the transmitter should be max 150' away and in line
of sight. Well, I'd like the thing to work at 275' and slightly out of
line of sight --around some trees and over a small hill.

I tried hooking the base unit antenna to the center wire of coax that
goes to our rooftop TV antenna but that didn't work. I can't quite see
the top of that TV antenna from the mailbox.

I'm getting the impression that I should find some way to boost the
transmitter signal. Any way to do this? The transmitter is powered by
2 3V lithium batteries. There's a Radio Shack provided parts list on
the web but I can't make much sense of it.

One thing I might try: Our detached garage is about 75' closer to the
mailbox than our house. The apex of the roof of the garage is probably
in line of sight of the mailbox. There is existing conduit for phone
wire from the garage to the house. I could probably run a long
"antenna" wire from the garage roof apex to the base unit inside the
house, but I wonder if the resistance (oh, right --impedance) of long
wire might throw cold water on this idea.

I know only of smattering of electrionics and certainly not much
analog. Any suggestions appreciated.

--zeb