Channel Jumper wrote:

If all you want to do is receive, it does not matter if the cable is 50
ohm or 75 ohm nominal impedance.. You are not going to get standing
waves from reception - only transmission.

Umm. Not true. Transmission and reception follow the same laws of
physics.

The reason you care for transmission has to do to some extent with
losses. If you have large standing waves you may actually be losing
power in the transmission line itself. Not to mention that with
a mismatched load you may not actually deliver much power to the
antenna, but that depends on the design of the transmitter, and of
the antenna tuner if one is present.

A receiver has a tremendous amount of gain and can compensate
for all sorts of mismatches - so you won't notice any difference
except on signals that are rather weak to begin with. It's at
that point you'll find that your transmission line has become
a notch filter that blocks certain signals without you knowing
it.

By building an antenna for a specific frequency band I am
assuming that that's what he wants to hear. For best reception
or transmission of any given frequency band and an antenna
designed for that band, go ahead and do the matching - why not?

Completely different thinking applies to random antennas typically
used for scanner listeners / SWLers. There, you accept what you
get for antenna performance and hope the gain in the first RF amp
compensates for a haphazard antenna / transmission line combination.

George Cornelius

Even better cable is the hardline that the TV cable company uses from
pole to pole. I think its nominal resistance is about 77 Ohm's, but its
loss rate is . 07 or something or another in like 100 feet @ 500 Mhz.

Enjoy the scanner, do not expect to hear much with a home brew vertical
dipole antenna.