I see someone is selling some stronger yagis on eBay (40" (spec'd at
24dB) for $100 and 60" (36dB) for $130). Assuming those specs are
reasonable, from your math here it sounds like I might end up "OK"...

My other problem is connecting any external antenna to the LX5450.
Apparently the external antenna jack/port is so weak that people are
breaking their 5450s (the internal soldered connection to the on-board
stubby retractable antenna) when they try to plug in an adapter, that
no one is making any adapters for this phone. I don't know if a
"clip-on" adapter would work for something like this. It seems like
someone could craft something that would work here...

Someone had also suggested I look into one of those "signal boosters"
or "repeater amplifiers" sold by Wilson and others for $350-$500 (that
apparently boost your signal to the max 3watts). 'Kind of
expensive...and would the result be comparable to the external antenna
options we're discussing here?

(Scott Townley) wrote in message
On the other hand, 100' of cheap RG-58 loses about 14dB/100ft at
cellular, a 300' run would be -42dB, and if hooked to a yagi on a
hilltop gives you -70+10-42=-102dBm at the end of the cable...weak but
probably usable. Problem is, it would have to be connected directly
to the phone. Not very mobile at that point :-) The instant you hook
up an antenna (to reradiate) you will lose at least 10dB right off the
bat (the first foot of distance from an antenna at cellular is -22dB
space loss).

You could get lucky though...if the hilltop signal were -50dBm (that's
pretty damn strong) and you splurged on 15dB yagis, you'd end up with
-50+15+15-70=-90dBm which would work fine.