Installing a CB in a 2015 Anthem

[Gary.Jones]

I needed my CB in my last coach exactly twice in two years, but both times told me what I wanted to know about a dead-stop traffic problem. Some nice trucker told me what was going on a couple miles ahead and let me move to the right lane. So, although it was largely unused, it was worth $80 to put a new one in this coach.

I bought a Cobra all-in-one mic sized CB for my new Anthem. I had been told that the coax for a CB had been placed already up in the dash. This afternoon, I went looking for it, expecting a coil of RG-8 or RG-6 or something similar up under the dash, but a thorough "feeling around" found nothing.

Anyone done this job before and able to give me a heads up where the coax has been hidden?

Gary

[MRUSA14]

Remove the side panel by your left foot and you will see it coiled behind there.

[Nowabeachbum]

Originally Posted by MRUSA14

Remove the side panel by your left foot and you will see it coiled behind there.

What Marc said!

[Gary.Jones]

Thank you Mark !! That will do it.... I will try looking in the right place .

Thanks for the quick response.

Gary

[jestal]

Gary, Let us know how the CB works. I have tried three different radios in our Anthem and none of them works with the Entegra supplied antennae and coax. There is no ground plane with the fiberglass roof and the mount on my coach is mounted into a square piece of thin metal that looks like a 4 inch square junction box cover. I could not get any sort of SWR reading no matter how I moved the antennae. I even tried taping down a layer o thick tin foil to the roof about three feet around the antennae base to create a ground plane and grounded it to the antennae base ground wire and the CB would still not transmit or receive from a handheld ten feet away that I know works. I, too, would like an operating CB but an stymied as to how to get one to work with what is provided from Entegra.

I am considering a dual firestick antennae arrangement that is designed for a non ground plane application but just haven't rationalized drilling holes in the front cap to mount them. They cannot go on the roof as I have had the existing roof antennae hit several bridges in Michigan and I know the firestick types would not live thru that , plus they are much longer. From previous experience a dual antennae with one on each front corner lower to the ground will work reasonably well as long as the antennae are next to fiberglass and not a metal wall.

I wish I knew a CB wizard near me to help design a system that would work.

[thatcher-227]

On an earlier post it was said that some antennas were not grounded properly. Something about a screw not being installed. Never did quite understand what they were talking about. Taking mine back for the 2 year PDI and will let the factory figure it out.

[Gary.Jones]

Jestal:

I am not an EE or rf engineer. I am a ham radio operator licensed for the past 50 years which makes me just knowledgeable enough to be dangerous.

I know very well your complaint. My last CB in my Dynasty with a roof mounted whip was terrible. If I got more than a mile or two away from another RV, we had no communication. It was very frustrating.

My ARRL antenna handbook has some information. CB Channel 19 is on the frequency: 27.185 MHz. A vertical antenna should be optimal at least 1/4 wavelength and have a good radial counterpoise. For most cars and trucks, the antenna is mounted to a steel support such as the mirror which is electrically bonded to the frame of the cab (the counterpoise), etc. Usually the antenna is in close proximity to the ground plane (frame). However, on our coaches, the antenna is much shorter than a 1/4 wave and it is nowhere close to a good ground plane. I am guessing, but I would guess that the only ground to the chassis is through the radio and the coax which provides some ground, but it depends on the quality of the ground from radio to frame of the coach.

The Handbook says that a quarter wavelenth at 27.185 MHz is 8.6 feet, so our verticals are much shorter than a 1/4 wavelength and with a poor ground plane, not expected to work well. Your idea of adding a tin foil ground plane is a good one, but my guess is that it was no where close to 1/4 wavelength in length. With amateur radio antennas, you ideally place wire or aluminum radials every 90 degrees around the base to provide the "minimum" ground plane. Ideally, they are 90 degrees apart. However, 1/4 wave radials in any orientation will help. One could put wire radials down both roof sides and one or two down the center of the coach and the radials would significantly improve performance. Unfortunately, a quarterwave in the Citizen Band is roughly 234 / frequency in MHz (234 / 27.185) which is 8.6 feet.

Now, I am sure that there is a rf engineer somewhere on iRV2 that can give us the definitive information. Any grounding of the antenna and radio through a very solid ground to chassis should help, and ground plane radials should help but there may be a better way. They say a 5/8 wavelength vertical needs no ground but that is impractical....

Gary

[MRUSA14]

Our antennas are electrically the right length, as the shortfall in length is made up using a loading coil at the base of the antenna. I am getting an SWR of 2:1 which is not great but is borderline okay. Like everybody else I get pretty poor distance transmitting but receiving is better. For the little bit of use that my CB gets, I don't plan on going to any great lengths to improve it

[Nowabeachbum]

Huh!?! Sorry Gary, but you lost me at "I am not an EE...".
I agree with Jestal. I would like to have a cb that I can pull out and use occasionally and it actually work. If that means I have to drill some holes, I want to be damn sure that it will be worth it and not just slightly better than what I have or don't have. The way they are now, I don't know why Entegra even installs the current one. Mine works about as well on its portable antenna.
Help Mr. Wizard!

[trvlguyjim]

RE: antenna

I have used the type that sticks to the windshield.
Also have the Cobra one hander.
Not going to work skip but should get road conditions. That's all you really need it for nowdays. Cell phones pretty much do the rest!

[jestal]

Thanks for the info Gary!

Entegra does provide a solid ground wire from the base of the antennae to a bolt on the chassis under the front cap down below the windshield. Based on observation and VOM readings the ground is there and seems fine and should be adequate. Not to mention names at Entegra but they did acknowledge the missing ground plane is a good portion of the problem but it would require glueing or attaching a metallic ground plane to the roof. Not impossible but not something cost effective for Entegra.

I know in a past life I dealt with antennae on deck lids that were composite material and we had to laminate a metallic layer in those deck lid layups to serve as the ground plane which adds credence to what I suspect about the fiberglass roof even with the good ground. It is nice that the ground is there to ground the ground plane should I decide to glue an aluminum sheet in place under the antennae.

I think I am going to duct tape a prototype system in place before I drill any holes and give the DW time to get used to "the look" as she cannot imagine a tacky pair of 4 foot antennaes parallel to the A pillar....

[Old Scout]

Interesting--using a CB radio today----no one to talk to anymore and nothing to say or hear--that is unless you want to learn new swear words or some nasty sex terms....my opinion.

[MRUSA14]

There are two situations I can think of where it would be useful. One is when traffic is backed up, the truckers can sometimes tell you where the problem is, how long the backup is, what lane to be in, or where to detour.

The other time is when two or more coaches are travelling together it helps keep in touch with each other.

[Gregory0495]

I am working on the problem as we speak entrega had rvone put a 18" sheet metal plate for a better ground plane. But my swr reading is still over 2 but the technician that did the plate forgot to check for ground continuity