JimK wrote:
- Terminate the random wire away from the
- electrical noise near the receiver by using
- co-ax and the balun.

Generally a Balun works best along with a
good earthen Ground {connection}.
.

Dave and RHF, thanks. I'll read up on the balun. What is the purpose
of impedence (or RF?) matching between random wire and coax?

Thanks,
Jim


Think of "impedance" as hose diameter. You can dump water from a skinny
hose (low Z) into a fat hose (Hi Z) but not the other way around (most
of the water is spilled).

The matching "Bal Un" is usually an autotransformer which converts the
450 Ohms (max Z of the random wire) to 50 Ohms (good match for RG-58,
RG-59, RG-6, RG-8X, etc.) Note that at resonance, the random wire is
already at 50 Ohms, so the transformer lowers it to ca. 6 Ohms, but it
works fine for receiving).

A second benefit is that the "BalUn" is DC grounded everywhere (provided
you ground the cable sheath where it enters your house per NEC). This
will keep static charges out of your radio. Your brother is right.
Whips are usually "active" antennas, with an extra transistor to convert
the Hi Z antenna to Low-Z, to match the EXT ANT input, which you should
use, if you have a proper coaxial deed.