Metra antenna coaxial cable

[Biba69]

This is a long shot, but does anyone know the designition of the type of coaxial fitting to Metra electric antennas? I need a short - five foot- coaxial cable for an installation (no place to hide the extra length). I found a place which had about two dozen different coaxial connectors/cables but none looked exactly like the female type for the screw on antenna connection for the Metra.

Or - and this should be simple, but I can't find a source - know where I can get a separate male plug which goes into the head unit's antenna connection?

Amazing how difficult it is to find short cables for automotive audio installations when everything goes in the tunk. I also need two sets of 2 foot male RCA patch cables for the head unit to the amp speaker connections. I've found a source for 1/2 meter RCA cables which, if my math is correct, is around 20".

Biba

[Tifosi]

19.6" specifically.

You could build your own RCA patch cables to any length/spec you want as places like Radio Shack have the ends as seperate parts and wire on the shelf.

A little time, a little solder and Bob's your uncle.

No clue on the coax.

[vangelislaz]

Coaxial cables aren't a problem to source them at all. Don't be worry for the different colors you see on them ( black, red, grey,blue etc). Usually, they are type of RG58 or RG59 ( industry basic color for both is Black). You can define them as RG59 has the inner wire of solid core, while RG58 uses a multi core one. RG 58 has a resistance of 50ohm , RG59 has 75ohm (RG59 is the most common coaxial for the TV installations). Most car antennas use RG59. Most shops for electronics or for Hams, have these common RF cables, have also whatever you need (adapters for extensions, as you asked).

Many car audios on the back panel , have a small hole for antenna's tuning.
In real, you get tune the whole system coaxial+antenna, since when you are dealing with RF sine waves each cm of coaxial counts. So, behind that small hole is a picoFarad variable capacitor ( inside the car audio), where you can trim for best SWR (Standing Wave Ratio) receiving. Practically, tune your radio around 100MHZ ( or find a weak Fm station), use a small screw driver (better a plastic one) and trim the small capacitor for a better input signal.
Keep in mind that car radios need always to have a good antenna for a good reception .This is true for any tuner, but here the situation is different than homes. We have interferences from alternators, sparks from the ignition and many other issues. Thats why , car radios are well caned, they are like a Faraday cage. Thus, without an antenna has a no receipt!
Be careful on the the coaxial's adapters. Must be of great quality ( they are cheap) and use at joint points a soldering iron

Now, If your car radio happened not have this back small hole, no problem. Make your installation with the proper joints and alternatively play with the antenna's slide extensions. Maybe , you can find a not so good reception with all the long of the antenna, make it shorter! Purists, might be experiment with
the coaxial's length, But I guess this is too much for our installations....

of course, a field which pays plenty of our attention must be the power filtering and the correct grounding of our car radios! Always must use a good power filter with a proper grounding to eliminate the interferences. This cames hand in hand with a proper antenna system.