On Friday, 15 March 2019 13:11:36 UTC, Fox's Mercantile wrote:
On 3/15/19 3:23 AM, wrote:

I never remember the numbers, so i will just describe it.

CB and low power ham radios use one type.
TV antennas use the other.

Communication radios tend to use 50 ohm coax.
RG-58 1/4", RG-8X 5/16" and RG-8 RG-213 1/2" (Roughly)

TV and most CCTV stuff use 75 ohm coax.
RG-59 and RG-6 5/16" and RG-11 1/2"

Both coax is about the same diameter and looks alike on the outside.

The 75 ohm is noticeably thicker.

I have a police scanner. It has an ext. antenna connector on the rear
that is one of those "Motorola jacks" (same as the ant. connectors on
car radios).

My question is whether it matters which coax is used?

It doesn't make much if any difference.
Don't let people wind you up about impedance matching on receive
antennas.

Co-ax impedance is not critical, but choosing rf rather than baseband co-ax is.


I dont know how well that antenna, made specifically for 162.xx mhz will
work on the UHF scanner bands

Generally, UHF is 3 times the VHF frequencies. What looks like a
1/4 wave whip antenna (16-18")on VHF will look like 3/4 wave on
UHF. And will work just fine.

Try it & see.


NT