Do I need a "No-Grounding-Pane" type CB antenna? What was installed OEM for 2005

[Mike Shumack]

My CB antenna is missing. There is an antenna mounting stud and a spring on the roof. Do I need a "no ground plane" type antenna?

I had not heard of this NGP type before, until I started shopping for the antenna.
This is what the webstore says on the subject:

Ideal for use on motorhomes, ATV's, motorcycles and other vehicles made of fiberglass or lacking a large ground plane area. The Firestik NGP replacement antenna is designed to be used ONLY with other NGP (no-ground plane) kits and coax cable. Using an NGP antenna with standard coax cable will result in serious performance issues.

I would think a NGP antenna is the right type based on statement above, but i also recall reading somewhere that these coaches have a large metal plate under the fiberglass roof (one in front and one in rear) to act as a ground plane (and there is a heavy green wire coming down from roof direction and grounding to chassis in the rear of coach, and I think there is one in the front too  (this may be for the grounding plane. I don't know).

The last sentence in the quotes says the wrong type of coax cable it will be a problem. How can U tell what type of cable/antenna is being used now?

[Bill Sprague]

Are you sure you want a CB antenna?  After you get it, you're going to have a hard time finding anyone to talk to.  In '04 or '05 there was still some value.  Back then I liked mine for figuring out traffic problems. Google Maps is far superior. 

There may have been a time when RVrs used channel 13 as a common frequency, but that stopped a very long time ago.

Between cell phones and family channel radios, better choices exist for traveling with friends.   Even the truck drivers seem to have given up on CBs.

[Mike Shumack]

Good point - but the CB is already installed (OEM) and the antenna mount is on the roof. So for $40 or so for the antenna, I would have a working CB.
But would I use it? - I don't know. My OCD makes me want to have everything in the coach working. So for $40 to satisfy that it's probably worth it. 

I just need to know what type of antenna I'm supposed to use.

[David T. Richelderfer]

The value these days for having a CB radio is if you are traveling with other RVs, then you can communicate a desire to stop at a rest area, see something scenic along the road, or that the next exit is the one to take, just for examples.  These things can also be done about as easily using a cell phone, but a cell phone only works for one-on-one communication versus a CB radio works for one-on-one, or one-on-two, or one-on-three, etc.

[Bill Lampkin]

Mike, There was a fiberglass NGP Firestick antenna on the coach when we bought it. Replaced like for like after a tree limb snapped the old one off. I installed a non-ngp wire antenna with a spring base (we actually have a CB shop in a nearby town) and it works. I can't get the thing tuned very well (the SWR is low, but only around ch 20, I think) but it works. I think the regular type antenna is the way to go. I, like you, sleep better when all works.

[Stan Simpson]

When we have someone traveling with us, we just give them one of our walkie talkies that we use while backing in, etc. They have decent range, and we can talk back and forth.

[Paul Meehan]

I just installed a 3’ Firestick antenna at an angle.  The old CB coax cable was defective so I bought a replacement NGP coax.  Hooked it all up this past Friday.  We were in a campground right on I-10 where I attempted to get someone to respond to me.  No replies.  I talked with a trucker the next day at a truck stop and he did not have a CB in his truck.
 I hope to use the CB when in rollin’ Rallies such as “Music to Branson” in a week or so.  I understand CBs are a good tool when stuck in traffic.

[Mike Shumack]

How did you get the new cable routed to the roof?
Were you able to pull the new cable through by connecting it to the old cable (no wire ties or clamps or obstructions in the roof)?

I see there are some weather channels on the CB too - that could come in useful while traveling.

[Paul Meehan]

Mike, my antenna was/is mounted at the driver’s A-pillar.  Threaded stud through the side-wall.  Adjustable ball mount outside.  Attached NGP cable ring lug to threaded stud.  Ran cable inside A-pillar trim panel then to radio.  I bet your cable is attached to the roof supports so probably could not fish/pull a new line.  I have read that if you add length to an existing coax the length should be in increments of 9 feet.
Good luck!

[Steve Huber]

Mike,
A pillar mount is relatively convienent but you will increase wind noise with it compared to a roof mount.
Steve

[Bill Lampkin]

Interesting article about radio antenna 'ground plane' I ran across a few years ago.

http://www.kiss-ssb.com/about.html

[Paul Meehan]

Steve, the antenna was already mounted on the pillar when we bought the coach.  I do have an unexplained amount of wind noise.  I bet it is the antenna mount.  Thanks

Paul

[Mike Shumack]

I just wan to install an antenna on the existing roof mount. I don't want to install new cable or a new mount,
I just need to know if I need a No-Ground-Plane antenna or a "regular" antenna.

I will call BCS. They may have the antenna I need - or know what i need.

[Keith Cooper]

 Lets see if i can dust off and simplify some antenna theory. A ground plane is a flat  horizontal conducting surface that serves as part of an antenna. The ground plane does not have to be connected to ground (no wires to the chassis are required). when an antenna is installed without a ground plane the effective power output, receiver sensitivity & transmission range of the antenna are dramatically reduced. Typically ground planes are sized with a radius of at least 1/4 wave length of the lowest frequency being transmitted or received. CB band range from 26.965 MHz for channel 1 to 27.405 MHz for channel 40. 1/4 wave for channel  1 is a little over 8.9764 feet.  A null ground plane aka no ground plane antenna uses the shield in the antenna coax to provide a ground plane for the antenna. That is why the coax is precisely 17.9529 feet long. the reason we tend to mount a firestick on the windshield A pillar is mounting it on the roof means we are more likely to break an antenna because of the height above the roof of the coach.
When we are on a rolling rally coaches will frequently travel in groups of 3 or 4 coaches. For those coaches to communicate  the choices are CB, Family Radio, Cell phone or smoke signals. Since we are frequently in areas with spotty cellular coverage that leaves us with either CB or Family radio's to communicate. When running a long rolling rally we tend to use all three over the course of the rally and in fact I carry 4 family radios so we have at least one way to communicate with the coaches that are traveling with us.

[Mike Shumack]

Lets see if i can dust off and simplify some antenna theory. A ground plane is a flat  horizontal conducting surface that serves as part of an antenna. The ground plane does not have to be connected to ground (no wires to the chassis are required). when an antenna is installed without a ground plane the effective power output, receiver sensitivity & transmission range of the antenna are dramatically reduced. Typically ground planes are sized with a radius of at least 1/4 wave length of the lowest frequency being transmitted or received. CB band range from 26.965 MHz for channel 1 to 27.405 MHz for channel 40. 1/4 wave for channel  1 is a little over 8.9764 feet.  A null ground plane aka no ground plane antenna uses the shield in the antenna coax to provide a ground plane for the antenna. That is why the coax is precisely 17.9529 feet long. the reason we tend to mount a firestick on the windshield A pillar is mounting it on the roof means we are more likely to break an antenna because of the height above the roof of the coach.
When we are on a rolling rally coaches will frequently travel in groups of 3 or 4 coaches. For those coaches to communicate  the choices are CB, Family Radio, Cell phone or smoke signals. Since we are frequently in areas with spotty cellular coverage that leaves us with either CB or Family radio's to communicate. When running a long rolling rally we tend to use all three over the course of the rally and in fact I carry 4 family radios so we have at least one way to communicate with the coaches that are traveling with us.

It is a complicated subject. Thanks for the information.
The CB instructions say, as you noted, I should use a 1/4 wave antenna but it doesn't specify a height as a requirement. As my coach's roof height is over 12-ft, I was only planning to get an antenna in the 3 foot height range (attached to the coil-spring mount).

But I still don't have the answer I'm looking for.
 
1) If the Coach was built for a "No-ground-Plane" antenna it would have the correct length coax cable already installed. So I just need to install a no-ground-plane" antenna.

2) If the coach was built for a "null-ground-plane" (has a metal plate under the fiberglass where the antenna is mounted), then I need that type antenna.

I can't find anything to support this now - but I think I read/saw somewhere that there is a large metal plate in the roof under the antenna mount location.

 I'm going to call BCS today - if they can help, I'll post back what they tell me.