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JeePak · 11-20-2009, 03:40 PM

So I just bought myself a uniden pro520xl cb radio and a 5' firestik antenna with a tuneable tip and am just wondering what coax cable would be the best bet?

I do a write up of my installation...I bet none of you have seen what I'm gonna do

**2000XJ** · 11-20-2009, 04:04 PM

I use RG-58A cable, and it works fantastically. You could also use RG-58U. Some places just refer to it as RG-58.

You don't need to go with your typical 18' length, you can go with 9' if it's more convenient. Just make sure you dial in your SWR properly with an SWR meter.

What is your setup going to look like? How creative are you getting with it?

JeePak · 11-20-2009, 04:59 PM

sweetness, yea 9' is about all i need. Im mounting the cb in the usual spot, inbetween the visors and the antenna will be on the rear taillight..but HOW i mount the cb is the idea lol

and thanks for the info

**ZackXJ** · 11-20-2009, 05:47 PM

cool, when I redo my interior cloth im going to do that, and make a box for it, that way it kinda looks like it should be there, but intil I do im leaving it mounted on the side of the center consol at the passager side.

**96sport** · 11-20-2009, 07:38 PM

Quote:

Originally Posted by 2000XJ

You don't need to go with your typical 18' length, you can go with 9' if it's more convenient. Just make sure you dial in your SWR properly with an SWR meter.

I thought that they recommend 18' because it helps with tuning

Carl48 · 11-20-2009, 10:13 PM

The coax can be any practical convenient length. It does not have to be a specific fraction of the wavelength when feeding a single typical 1/4 wave vertical antenna.

88fadedglory · 11-21-2009, 12:06 AM

Sorry, guys, but who ever told you that coax had to be multiples of 9' didn't know diddly about two-way radio installs. I don't care if he is a HAM.

First, coax doesn't let the radio signal travel at the speed of light ("C" in Einstein's famous equation) like it does in free space but more like .66C or only 122894.64 miles / second. This is normal for most foam communications coaxes.

There are some exceptions, but they are either hard to find, require special connectors or pricey

So, the coax would need to be cut to a shorter length to be a resonant fundamental 1/4 wavelength or multiple of a 1/4 wavelength. Two thirds of 9' is 6', of 18' = 12', and so on.

But then you get situations like a 108" GlassKat fiberglass whip on a ten-speed bike (mounted to the rear luggage rack) with 5.25' (Definetly not a resonant length) trimmed to a 1.1:1 SWR ... and Burmuda on skip with a fence charger battery and an old Radio Shack Mini-23 ... barefoot from central IN. Ya see, it was my bike . . . .

Sharp bends and pinches are more of a problem than length. Cut the coax to fit with minimum length and no sharp bends or pinches and you'll be fine.

Add the best antennas, preferably either full quarter wave (108" overall) or top-load fiberglass and you'll get your best performance. Firestiks are great, btw.

Budd (Canon City Boogieman, KBH-4658)

JeePak · 11-21-2009, 12:49 AM

mmmmmmmmmmeeeeeeeeeerrrrrrrrrrrrrrrrrrrrrrrrrrrrrr rrrrrrrrrrrrrrrrrrrrrrrr.... that was what you just said flying over my head... lol

Carl48 · 11-21-2009, 04:45 AM

It's simple...again...the coax in your XJ can be any practical, convenient length...whatever it takes to get from the radio to the antenna. The important thing is that it not be damaged (pinched or kinked) and be sure the terminations are done correctly.

JeePak · 11-21-2009, 11:09 AM

sweetness lol thanks all

**WJCraig** · 11-21-2009, 11:33 AM

The other thing I found that will have a big impact on performance is a good ground. So many people don't ground their stuff properly, and it really causes a negative performance effect.

88fadedglory · 11-21-2009, 03:13 PM

Quote:

Originally Posted by WJCraig

The other thing I found that will have a big impact on performance is a good ground. So many people don't ground their stuff properly, and it really causes a negative performance effect.

Yep. You're right, Craig, and I spaced it out.

( "Earth calling Budd ... Earth calling ... now why am I getting an 'out of order signal . . .????"

)

Insure the antenna base or the coax shield, if it connects to the vehicle body, has a good ground connection and ground the case to your transceiver as well.

This reduces the possibility of interference getting into the antenna system and can lower your SWR significantly.

There's a product called "Oxy-Gard" (or spelled something like that)available which seals out corrosion while alowing good electrical connection ... also works good on battery terminals. Check local hardware and electrical supply shops.

Budd

5-90 · 11-21-2009, 03:40 PM

Quote:

Originally Posted by 88fadedglory

There's a product called "Oxy-Gard" (or spelled something like that)available which seals out corrosion while alowing good electrical connection ... also works good on battery terminals. Check local hardware and electrical supply shops.

Budd

You're probably thinking of "Ox-Gard" by Gardner-Bender - a one-ounce tube comes on a blister pack with a red/black card, and you'll find it in your hardware store's electrical section (if you don't, ask them to carry it.)

I use the stuff everywhere - but I'm awfully picky about electrical work.

I find it a bit "light" for battery terminals, but it can work. Just inspect and reapply PRN roughly quarterly.

**2000XJ** · 11-23-2009, 01:09 PM

Quote:

Originally Posted by 96sport

I thought that they recommend 18' because it helps with tuning

Quote:

Originally Posted by 88fadedglory

Sorry, guys, but who ever told you that coax had to be multiples of 9' didn't know diddly about two-way radio installs. I don't care if he is a HAM.

First, coax doesn't let the radio signal travel at the speed of light ("C" in Einstein's famous equation) like it does in free space but more like .66C or only 122894.64 miles / second. This is normal for most foam communications coaxes.

There are some exceptions, but they are either hard to find, require special connectors or pricey

So, the coax would need to be cut to a shorter length to be a resonant fundamental 1/4 wavelength or multiple of a 1/4 wavelength. Two thirds of 9' is 6', of 18' = 12', and so on.

But then you get situations like a 108" GlassKat fiberglass whip on a ten-speed bike (mounted to the rear luggage rack) with 5.25' (Definetly not a resonant length) trimmed to a 1.1:1 SWR ... and Burmuda on skip with a fence charger battery and an old Radio Shack Mini-23 ... barefoot from central IN. Ya see, it was my bike . . . .

Sharp bends and pinches are more of a problem than length. Cut the coax to fit with minimum length and no sharp bends or pinches and you'll be fine.

Add the best antennas, preferably either full quarter wave (108" overall) or top-load fiberglass and you'll get your best performance. Firestiks are great, btw.

Budd (Canon City Boogieman, KBH-4658)

Quote:

Originally Posted by WJCraig

The other thing I found that will have a big impact on performance is a good ground. So many people don't ground their stuff properly, and it really causes a negative performance effect.

Tons of good info above!!

With a CB install, take your time, tune it correctly, and enjoy it.

A great resource for information is here: Tech-Docs Index

I also agree that Firestik makes a great antenna. I've owned three of them so far, a 4', 3', and 2' and I've been able to get great SWR measurements with all three. They're really easy to tune, and work really well.

88fadedglory · 11-23-2009, 03:20 PM

Quote:

Originally Posted by 2000XJ

Tons of good info above!!

With a CB install, take your time, tune it correctly, and enjoy it.

A great resource for information is here: Tech-Docs Index

I also agree that Firestik makes a great antenna. I've owned three of them so far, a 4', 3', and 2' and I've been able to get great SWR measurements with all three. They're really easy to tune, and work really well.

The best mobile antennas I ever had were 5' UglyStiks top-loads. They might have been Shakespeare products, but I don't think so (1977). Biggest claims to fame: 2.1Db gain each and unbreakable.

A pair, co-phased just rear of the back glass on a 65 Dart, then the top loads were leaned outward to 8' 6" (6" over max legal highway width for about 3Db gain)). That setup was as directional as a beam antenna. No range (a couple city blocks maybe) off the sides, a couple miles off the back, but I could walk over base stations off the front.

My radio was a Radio Shack Mini-23, which I still have and still works.

It was fun to drive down the road looking like a four-wheeled set of TV rabbit ears . . . smacking road signs, making those pedestrian clowns that crowd a curb jump back . . . . .

Budd