Fiberglass motorhome, needs antenna...

[jassing]

We bought a small fiberglass motorhome. Adding a sufficient ground plane is not easy as there isn't enough free flat space on the roof.
So this leaves me with using a no-ground plane antenna.

For ease of install, there's the side mirrors. For added height, I could travel the distance (under the carriage) to the rear where there is a ladder I could attach it; bu then I risk taking it out at underpasses and trees.

I do not want to drill the fiberglass as there is no easy way to put a proper backing plate w/o tearing up the interior.

So I think that leaves me with the only real place of the mirrors. I have been partial to ugly firestik antennas, as (for me) they have proven to take abuse on my 4x4 rigs; but I have never used their no-ground plane antennas.

Does anyone have experience with any no ground plane antennas?
I know dual antenna's offer more "directional" -- I am more interested in trying to get out in all directions (realizing that the RV itself will block some); will dual antennas result in less coverage in side-to-side directions than a single antenna? Or will duals just result in more forward-rear direction coverage?

I seem to recall an experience that a dual antenna resulted in more forward/rear coverage and less side to side coverage, but can't locate anything to back that up.
Basically, if a single antenna gets out "in general" as good as a dual antenna, simple is better... but if dual antennas provide direction AND additional coverage, then I'll go that route.

Thanks.

 

[prcguy]

Do you have a Scamp or Casita or similar? Have you considered making a ground plane on the roof using something like 2" wide aluminum ducting tape? Ideally it goes on the inside of the roof but I've done external tape ground radials on my fiberglass Casita and it works great. I also have a solar panel on the roof and use the aluminum frame of the solar panel for a partial ground plane suplemented by some 1" wide copper tape radials stuck to the roof.

I would also consider a base loaded antenna with thin whip so if you hit something there is not much mechanical force transferred to the roof. A fold over feature would also be good.

We bought a small fiberglass motorhome. Adding a sufficient ground plane is not easy as there isn't enough free flat space on the roof.
So this leaves me with using a no-ground plane antenna.

For ease of install, there's the side mirrors. For added height, I could travel the distance (under the carriage) to the rear where there is a ladder I could attach it; bu then I risk taking it out at underpasses and trees.

I do not want to drill the fiberglass as there is no easy way to put a proper backing plate w/o tearing up the interior.

So I think that leaves me with the only real place of the mirrors. I have been partial to ugly firestik antennas, as (for me) they have proven to take abuse on my 4x4 rigs; but I have never used their no-ground plane antennas.

Does anyone have experience with any no ground plane antennas?
I know dual antenna's offer more "directional" -- I am more interested in trying to get out in all directions (realizing that the RV itself will block some); will dual antennas result in less coverage in side-to-side directions than a single antenna? Or will duals just result in more forward-rear direction coverage?

I seem to recall an experience that a dual antenna resulted in more forward/rear coverage and less side to side coverage, but can't locate anything to back that up.
Basically, if a single antenna gets out "in general" as good as a dual antenna, simple is better... but if dual antennas provide direction AND additional coverage, then I'll go that route.

Thanks.

 

[radioman2001]

I don't know what frequency you are looking to use, but for UHF I use a 1900 electrical box with the 3/4 in hole and screw it down on the roof after applying lots of RTV. For VHF I use a cookie sheet and do the same, and both require you to drill hole in roof a little larger than a NMO mount to run the coax down. If you don't have enough room for either of those flat copper grounding straps can be used on the outside by following the roof line and just either RTV'd and or screwed down with SS screws.

 

[jassing]

Do you have a Scamp or Casita or similar? Have you considered making a ground plane on the roof using something like 2" wide aluminum ducting tape? Ideally it goes on the inside of the roof but I've done external tape ground radials on my fiberglass Casita and it works great. I also have a solar panel on the roof and use the aluminum frame of the solar panel for a partial ground plane suplemented by some 1" wide copper tape radials stuck to the roof.

I would also consider a base loaded antenna with thin whip so if you hit something there is not much mechanical force transferred to the roof. A fold over feature would also be good.

Yes. I have considered creating a ground plane, and dismissed it as not a good option. Tape would not last on the outside, and on the inside would be hugely destructive to get on the actual inside of roof.. Additionally, there is no good place to mount the antenna on the roof, I'd have to tear the interior apart to attach a backing plate.
And no, it's not a scamp, it's a small class A motorhome.
Good idea about a base loaded whip... I"ll look for a ngp whip...

 

[jassing]

I don't know what frequency you are looking to use, but for UHF I use a 1900 electrical box with the 3/4 in hole and screw it down on the roof after applying lots of RTV. For VHF I use a cookie sheet and do the same, and both require you to drill hole in roof a little larger than a NMO mount to run the coax down. If you don't have enough room for either of those flat copper grounding straps can be used on the outside by following the roof line and just either RTV'd and or screwed down with SS screws.

Frequency? 27mhz, since it's a CB, I thought that was obvious...

Sorry, I thought I mentioned that creating a ground plane on the roof was not an option...
if it were possible to delete the thread, I would -- I guess I wasn't clear in my thoughts.

 

[radioman2001]

You could look into some no ground plane antennas, Havn't used them and I don't know if even available anymore

 

[jaspence]

A marine antenna designed for fiberglass boats should work, but the length could be a problem as they are half wave. See Marine VHF whip antennae - what are they? for more information about this type of antenna.

 

[FiveFilter]

Yep, it should be a given that a post in the CB forum would imply it pertains to 27MHZ.

I don't use one, but have read that no-ground-plane antennas can work well, but at somewhat of a reduced capacity. In any case, it's probably the most practical way to use CB on a composite rig.

 

[cmdrwill]

There are 'half wave' type mobile antennas for 27 mHz made by Larson, Comtelco, and other commercial antenna manufactures.

 

[BloodandRoses]

Larsen makes a good one...