Re fit (in my head?) tv coax and 11 meter

[Turbogus]

Greetings all, from Oregon ~ the shower me state,
My best friend just bought an '88 Dodge conversion van. Nothing much special that I didn't homebrew in my Econoline but his is equpped with a Uniden 510 that has a PL -259 connector out the back of the radio and RG mini 8 or 213 that disappears from the ceiling mounted cabinet into the headliner, we found a junction in the port side wall that checked out with continuity but the end terminal appears to be a tv cable connector and coax. I'm thinking I may have to re wire the whole dang thing unless tv cable has progressed to be able to accomodate 11 meter propogation. What do you think?

Thanks and a lift of the lynch lid.

Gus

 

[Turbogus]

I only had a cursory look at the coax (through fogged up windows thanks to the Oregon autumn climate) called my friend early this morn and given it's small diameter I think we're dealing with mini 8, going to rewire regardless.

 

[W5LZ]

The biggy, besides the connector on the end of that TV coax, is that the typical TV coax has an impedance of 75 ohms. Matching that (making everything compatible) to the rest of the system, 50 ohms, can be a real 'booger'. That TV coax should be able to handle any 'stock' CB radio with no problems as far as power and frequency is concerned. Getting the "SWR's" into a reasonable range is the problem. (And soldering to that braid which is typically aluminum.)
That RG-213 or RG-8X just 'ain't no thang', ought to handle anything you'd put through it at that length of run.
-'Doc

 

[Beetle]

IF the feedpoint impedance of the antenna is exactly 50 ohms, non-reactive, the 75-ohm RG6 would represent a mismatch of only 1.4:1. Many mobile antennas have impedances down around 30 ohms anyway, which is why "magic" lengths of 18 feet are considered to be sacred.

Nothing to keep anyone from experimenting. RG-6, as Doc mentioned, has an aluminum shield, meaning that you MUST crimp whatever connectors you use. RG-6 is a perfect fit for the "F" connector, such as most TVs use as 75-ohm coax inputs, and there are adapters from "F" to "UHF" and back again.

As I said, there's nothing to keep anyone from experimenting to see what works in their particular case and what doesn't.