Ralph Mowery wrote:


Want to install a single (or maybe two) not too large or fancy small
whip-type "all-band" antennas on the eaves of a residence and run cables
to BNC jacks inside, for scanner listening in the 25-50 MHz, 100-160
MHz, and 450-490 MHz bands, and am trying to decide between a less
desirable antenna and scanner location but with only about 3 to 4 meters
of cable run, or a more desirable location for antenna and scanner but
with maybe 7 to 10 meters (25 to 30 feet) of cable run.

Question is, if I use good 50 ohm coax how serious would the cable
losses be for 20 to 30 feet of cable in the above bands (with the
100-160 MHz band probably the one of most interest)?

Use any cable 1/4 inch or more in diameter , YOu will not notice it up to
500 mhz for only 30 extra feet. Best bet is some rg-6 cable if you can find
some that has a copper shield or if you have a good way to make a connection
to the shield as some is aluminum. RG-8x is good for a short run. Don't
worry about the impedance of 50 vers 70 ohm cable. It will not effect your
receiver coverage.

I will add to what Ralph said that the most likely place for "signal
loss"
will be at the connection(s) you make at each end of whatever coax you
use.
Buy some good quality pre assembled coax if at all possible. Avoid Radio
Shack junk.

I will add to what Ralph said that the most likely place for "signal
loss"
will be at the connection(s) you make at each end of whatever coax you
use.
Buy some good quality pre assembled coax if at all possible. Avoid Radio
Shack junk.

That remimded me of some pix I saw of a cut away of a RS connector , maybe
it was L type where a spring or coil of wire was used. That thing acted
almost like a RF choke and had a very high loss.