CB Radio Antenna Recommendations?

[KCKKen]

Hi Everybody!

I have an original Delco AM/FM/Cassette/CB Radio that I want to install in my 85 GMC and am curious as to what others have used for the CB antenna. I would prefer something less obtrusive than the whip antennas from days gone by. Thanks in advance for helping me out!

 

[WebMonkey]

anything other than a 102" steel whip will be a compromise.

so armed with that knowledge, ANYTHING will do.

lil will magnet mount, 3/8-24 stud mount on the bed rail, whatever you think 'goes best' with your vehicle.

good luck!

 

[Doppleganger]

My Dad had a 75 Mercury Montego when I was a kid. One thing I remember about that car was that it had a factory AM/FM/CB head unit.....and the antenna was power in the front fender. Looked normal except for the center of the antenna halfway down being about an inch in diameter.

I've got a CB I'd like to use but pretty much just for the weather bands.

https://www.ebay.com/itm/295096831888

 

[Radiohead]

You could use the standard antenna cable to listen to CB in a diminished capacity off the broadcast antenna already on the truck, but like WebMonkey says, anything less than a quarter wave length will be disappointment from a transmission performance standpoint.

Cool find, that style of in-dash radio. Put up a pic when you get it going.

 

[Matt69olds]

Can you connect an aftermarket antenna to a factory Delco radio/CB combination? It’s been years since I have seen one.


I have a CB in my Ram, my wife makes fun of it any chance she gets. I have a Wilson 1000 I keep behind the backseat, I put the antenna on when I want to use it.

The Wilson 1000 is a long antenna, and my truck is pretty tall. The antenna does hit things frequently, removing the antenna when not in use is a good compromise.

 

[Radiohead]

Hi Everybody!

I have an original Delco AM/FM/Cassette/CB Radio that I want to install in my 85 GMC and am curious as to what others have used for the CB antenna. I would prefer something less obtrusive than the whip antennas from days gone by. Thanks in advance for helping me out!

Can you post up pics so I can see the back, or wherever the antenna cable attaches? I only remember seeing an RCA style socket but I wonder if an SO239 jack is there too

 

[smullen]

Interesting topic.

I have never seen a Am/FM, Cassette, CB radio all in one unit.

Also, Antennas are a funny thing.
I don't think most of the really small antennas you see going to preform very well in comparison to the long Ugly Whips as they are of a certain length for a reason.

I mean I have built several ""Base Station" Antennas for Amateur Radio/Ham and GMRS. For that, there are many antenna calcs where you can plug in your range of interest and it will tell you how long the antenna needs to be to be tuned for a given freq or range.

Also, you need too or should pay attention to something called SWR. Standing Wave Radio or Reflection. The lower the SWR the better, IF you hook a CB or any radio transmitter up to a improper antenna or badly tuned antenna, key up/transmit and the SWR is too high, you could damage the antenna, but more than likely you'll burn up the radios output. I actually have a meter for this that I always plug in between my transmitting radios and my Antennas. It also tells me how much wattage I'm putting out too.

The CB Radio spectrum is sliced up into up into something like 40 channels, ranging from 26.965 to 27.405 Mhz. Also known as the 11 Meter band.
Based upon that given frequency and using one of the various calculators, you should be able to punch in 26.965, 27.405 Mhz or somewhere between the two and it should give you the length needed to correctly tune the Antenna to.

What is strange though, is I have built several 2meter and 6meter antennas base station type antennas in Moxon, Jpole and Dipole configurations, but I have never built an antenna for a vehicle in these, I always just bought them.

I'm having trouble finding a calculator that can give me the data I want to see for a mobile type antenna.
I can find plenty of them for the three types I listed a few lines above and a few others, but not for mobile.
I know they make Amateur radio, GMRS and CB in Mobile form, so I should be able to find it for them...
Now I'm getting frustrated. I'll have to ask some of my radio nerd friends.

 

[85K304SPD]

I have a couple of old CBs that I would like to put back into service. I am not sure what type of antenna to use, and what is the advantage of one type over another. Dual short antennas, or a single "whip". Maybe somebody can explain a little bit about it for us that don't know how they work...

 

[Radiohead]

OK, let me try. For a dual whip CB installation, in our application (squarebody trucks), the necessary distance from each antenna is insufficient. The reason you see dual whips on the Large Car is you need a minimum of 8' separation between antennas (a quarter wavelength roughly) to get the effect twin whips generates - a figure 8 pattern that runs front/back, for more gain up and down the road and a bit of attenuation on the sides. You will never get it to work properly on a square because they aren't 8' wide foremost.

So Radiohead, why do we give a $#!t? Because a single antenna will give better results in our application. Placement on the vehicle will make some difference in the strength of the radiation lobe as well, and most people aren’t interested in mounting an 8' whip dead center on the roof. You can mount on a rear corner and have the majority of your energy go forward, which is sufficient for most people.

What else you want to know? Just know, the answers can get a little complicated for the uninitiated but it's not really too hard to grasp. One constant, short antennas are a compromise of a compromise. For maximum mobile efficiency, you need to use a quarter wave driven element, which on CB is 108".

 

[Snoots]

You can't beat a Shakespere Lightninng Rod!

 

[85K304SPD]

Well, my mind is blown already!! Thanks for the lesson. I didnt realize that it was all about wave length. So a whip mounted right behind the cab on the headache rack or the toolbox is about as good as it gets on a square body? What would be the difference between that and having a 4 or 5 foot antenna mounted in the same location? Is it how far you can transmit and receive from?

 

[Radiohead]

Hold on a sec, I see where my brief tutorial could use a little McGuires and a buff pad.
Think of the radiated rf like this: if you mount the antenna at the right rear corner of the bed, the majority power will be concentrated in the direction of the left front corner. IOW, the rf will use the metal of the truck as a reflector (as well as the truck body being the other half of the quarter wave antenna system - more on that later) and it "points" the signal along the plane of the most metal. Are you with me so far?

If you really want to go down the rabbit hole of transmitting rf from your favorite mobile platform, visit this site. Bring lots of duct tape.

KØBG.COM

A Web Site For Mobile Amateur Radio Operators

www.k0bg.com

 

[Radiohead]

OK, about shorter antennas. Think of a 4 or 5 footer as half as efficient as an 8 footer. It has to do with efficiency, sort of like running long intake runners for high end. (I might have that backwards, scraping Engine Masters memories here), you can't make low end power with long runners, right?

Mounting on the rack, dead center of the cab will give you the best 360° coverage possible. And as always, the higher the better.

 

[85K304SPD]

Clear as mud!! haha. Not really. Thank you for sharing your knowlege. I am getting it. I am not going to go down the rabbit hole on the rf, I may never make it out. When I was a kid, "everybody" had there whip antenna mounted on the back of their tool box, now I know why. On my '85 there is an antenna base on the top of the cab, at the back, no mast though. There is also a mounting plate on the inside of the roof, just above the rear view mirror, I am assuming for the CB. I never really paid much attention to it. Now I am interested!

 

[DoubleDingo]

Makes sense why the military has the long whip antennas on their vehicles. I guess one could tune a smaller antenna for around town, and tune a long antenna and keep it handy for traveling on the open road or for sticky situations. Each would be tuned, so SWR would be good to go.