best antenna to go with a cobra 29 LX chrome lcd CB

Antennas dont match the radio, they need to match the vehicle.

Also, If you are trying to use a truckstop antenna(like firestik wilson etc) with the factory truck coax, results will be poor due to the multi-band width and impedance of the factory setup.

If you are able, run a single antenna(longest you can get by with) francis antennas as mentioned, work well, and your own coax directly to the radio. Completly by-pass the factory setup.

Hope this helps

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To the original poster, Francis is a brand of CB antennas. The Francis antennas are broad band antennas but they are not pretuned as some suggest. They are quite good for legal power setups. Please note that Francis antennas do not do well with high power CB radio setups such as those with an amplifier.
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.The Francis model CB25 is a 4 1/2 foot long antenna and is a good choice if you have clearance problems. The model CB26 is 5 1/2 foot long and is also quite good if you have no clearance issues.

 

The SRA 198 is a Ranger Microphone......Top shelf for 22 bucks online!
I run them on all my radios.
The factory coax on about all of these newer trucks is terrible.
It runs through a diplexor that uses the same antennas for CB,AM-FM and TV.
Total crap for CB radio use.
The Francis 5.5 Hotrod is a great antenna if it is not too tall for your setup.

A higher power radio then I step up to the Wilson 2000 trucker with single coax.

 

Just for the record, a broad banded antenna has a very low Q which means it's not very efficient and a narrow band antenna has a much higher Q which means it is much more efficient within its bandwidth. A 50 ohm dummy load is very wide banded but it does not function as an antenna. If you're going for maximum efficiency you would want the narrowest banded antenna you could find with the highest Q but if you're looking for something to just slap on the truck and make your radio happy then a wide banded antenna with a lo Q is what you are looking for.

 

What is the best size for this antenna, I was looking at 4 or 4 1/2 foot and should you run single or dual?

 

What kind of truck ?

 

2012 Cascadia

 

A single wire antenna has always worked well for me.

 

Do you plan on using the factory antenna mounts ? Is that the model where they are located on the side bunk area ? If you do plan on using those mounts 4' would work fine , but just to be sure , like Rabbi recommends, measure from ground to mount, subract from 13'6", and that would be your max antenna height. I believe the factory stock antennas are 3 1/2 feet and Francis does make a 3 or 3 1/2 foot antenna. Now if you plan on using a bracket that attaches to mirror arm base, obviously the mounting location will be lower and you will have to use a 5 to 7 foot antenna, I know Francis makes a 5 1/2 foot one.