"John Dos" wrote in message
ink.net...
I'm trying to build an antenna for my 40 channel transceiver. But the
(female) RCA connection (at the feedpoint) is throwing me off. Is it 50
ohm
or 75 ohm?


Hello, John (perhaps)

The reality is that it isn't the connector, it is the coax. Typically, cb
and ham radios these days have a 50 ohm impedance. The connector has
nothing to do with it; it is all in the coax. Purchase 50 ohm coax
(assuming you will be using the usual vertical).

Should one use a dipole, the impedance is 72 ohms (but varies considerably
as can a vertical based upon the ground type/conductivity locally). Would
you believe that a vertical over perfect ground (salt water is quite close
enough, thank you) exhibits an impedance of only around 36 ohms?

The SWR of a 72 ohm dipole (again, it varies considerably based upon ground
and mounting height) fed by that 52 ohm rig is not anywhere severe enough to
cause a problem.

Most problems will be caused by poor grounding (especially in a mobile
installation), poor solder joints, or lousy coax (such as coax which has
been exposed to many summers and winters and expecially if it hasn't been
properly prepared for the elements).


Best regards from Rochester, NY
Jim