Question for you CB wiz kids, Antenna mount?

[FIRE UP]

Ladies and Gents,
We have an '04 Itasca Horizon, 36GD with the 330 CAT. It came pre-wired with a C/B antenna mount, antenna cable and wiring under the dash, just to the left of the drivers left knee. I have mounted and set up a Cobra 29NW. Now, for the most part, I use a small or, short I should say, 24" Firestik antenna. My range, for the most part is adequate. I don't try and talk to the next state, only folks or friends I'm somewhat near, as in around say, 1/2 mile or less. And even then, it's not all that great but, it works as needed.

Now, here's the deal. My antenna mount, factory style, is very flimsy. When I attach the shortie 2' Firestik, there's quite a bit of flex in that area immediately around the antenna base. In my opinion, the base is NOT attached to any structural member of the roof what so ever. In my opinion, it's only attached to the fiberglass sheeting.

And, if that's the case, then how in the world is it getting any form of a "ground plane" that all (as far as I know) C/B antennas need to operate properly?? Could there be a wire attached to the base of the antenna mount, under the fiberglass sheeting, that ties into the framing someplace to acquire its ground plane? There are no signs of stress cracks or anything like them around that antenna mount. The 2' Firestik has been matched to the radio for a close SWR.

And, since the mounting system, fiberglass only, seems so weak, that's why I choose to use a lower profile, 2' Firestik instead of what might be a higher, more capable antenna like a 4' Firestik. I figure there's quite a bit of stress on that mounting system by wind force alone, much less any low hanging branches etc. in many camp grounds.

Now, please don't suggest I remount the antenna on the side of the coach and rewire my whole C/B system. It's not that important of an item to take on such a remodel. It gets used, but not all that frequently.
Scott

 

[Keith4001r]

If your antenna is mounted on the roof a 2' whip is about all you're going to be able to use. I don't know of a shorter antenna unless you build it yourself, and I don't think your range will improve.

If I were setting up a new CB system, here's what I'd do-
I'd stay with the Firestick (good antenna) and Cobra NW and get a good noise cancelling mic. Turner Road King 56 (about $60.00) is the best, IMHO, been using them for years. Find a radio shop in a truck stop and take your radio in for a tune up, usually less than $25.00. They will boost your output from 5w to about 8 or 9w, boost your modulation from about 50% to 75 or 80%. Look in the travel store of the truck stop and get an external speaker with built in talk back (I've been using a "Diesel" brand for about 5 years, about $25.00).

I have been an over the road truck driver for 26+ years, this is the setup I'm running (with the exception of the antenna, I run a Wilson, and radio, I use a Cobra 25). You will be able to set the external speaker so you can hear yourself to adjust your Dyna-mic/ Gain to just before it feeds back. You will sound as good as any radio you hear out there, and your range will be a solid 1/2 mile, weaker but still clear out to a mile. Beyond that? Roll the dice.

If I may offer some unsolicited advice, listen 98% of the time until you get the feel of a conversation. These guys and gals are being pushed hard by dispatch and sometimes don't have a lot of tolerance for rookies. Some drivers want to talk, some don't. And please, PLEASE! Don't EVER call anyone Good Buddy! It has a whole different meaning than it did years ago! (PM me if you want to know more).

Best of luck.

 

[FIRE UP]

Keith4001r,
I surely thank you for your input on this. It's kind of ironic that you mention the "tune up" thing for the radio. We have a gent that lives only a few miles from us that has a shed next to his house that's all set up for "high performance" C/B stuff. He's got a dozen C/Bs hanging around that have been in for much of what you said to do to mine. He mentioned the "Talk back" thing too. He explained it but, it still went over my head. He would also tweak it some for better output etc. I might take it down to him, not sure. It works and works well for it's basic setup and application. So, again, thanks again for your input, very much appreciated.
Scott

 

[Luckiest Dreamer]

As I recall the antenna set up is checked with an SWR meter. It has accepted tolerances that is needed. There are two types of antennas. One that is designed for attaching to fiberglass and one for metal. Yours may need replaced if all you can get is 1/2 mile on a regular basis. Even my handheld will get 1/2 mile (that is if I turn it on) I spent a working lifetime trucking and have learned to disregaurd 90% of what is said on a CB. The other 10% was considered BS! Maybe I should say just Conversation.

 

[whem2fish]

You probably have a no ground plane antenna firestik I do

 

[John From Detroit]

This depends a lot on what your Motor Home is made of... Fiberglass is good, Diesel Pushers are not.

Consider Jeep 3" Tube Bumper CB Antenna Mount Bracket 11503 88 | eBay

This is an E-bay page. but something like this, bolted to a frame rail at the back of the RV might just do the job.. Though normally I say "Height is might" truth be told if mounting it higher means you have to comprimise the antenna by making it shorter, This sucker can (on most RV's) take a full quarter wave and not go over 13'

Depending on the RV you may have to play with the design a bit

For example on mine, if I choose to do that (I do not) I'd mount a very simle corner bracket bolted to the back of the frame rail with the proper size hole and the antenna goes up from there.

Another mount is teh Velvac mirror arm, NOTE this is very THICK metal so a standard 3/8" Snap in mount... WILL NOT WORK You need a mount that can go in a thick arm.

Another option (I may yet try this) is to put the aforementioned corner bracket (only lighter in wieight) on the side of the mirror arm or the mirror arm bracket (The part that mounts to the vehicle) this means an exposed connecdtion on the coax, but hey, Done that before. USE NGP antennas for this type of mount, Mirror is no where near a CB ground plane.

 

[FIRE UP]

You probably have a no ground plane antenna firestik I do

Well Sir,
The Firestik I have was given to me to try out and see if it would work. I have no idea if it's a "non-ground plane" antenna or not. I don't think it says anything on it about it. Well, it does work, and, at times, it (and or the radio) gets out for quite a distance. As for guaranteeing a range, without modifying a radio for higher power and output, that has always been a hit and miss thing. Terrain, buildings, distance, electrical interferences, skip, hills and much more have effects on just how far a standard powered C/B will get out.

I'm not so much concerned about how far it gets out as much as I'm more worried about the stress even that little two footer is putting on the mere fiberglass thin skin up there on the roof. If I could figure out a way, I'd somehow tie into a rib or some part of the steel or wood structure that would be close to the hole for that antenna. I love this coach but, that antenna mounting system is pretty poor for Itasca's normal quality.
Scott

 

[JamesAdam-WO]

The Solution Sir.
Use a Non Grounded CB Antenna, such as you would use on Marine Applications. This works.
JamesAdam

Ladies and Gents,
We have an '04 Itasca Horizon, 36GD with the 330 CAT. It came pre-wired with a C/B antenna mount, antenna cable and wiring under the dash, just to the left of the drivers left knee. I have mounted and set up a Cobra 29NW. Now, for the most part, I use a small or, short I should say, 24" Firestik antenna. My range, for the most part is adequate. I don't try and talk to the next state, only folks or friends I'm somewhat near, as in around say, 1/2 mile or less. And even then, it's not all that great but, it works as needed.

Now, here's the deal. My antenna mount, factory style, is very flimsy. When I attach the shortie 2' Firestik, there's quite a bit of flex in that area immediately around the antenna base. In my opinion, the base is NOT attached to any structural member of the roof what so ever. In my opinion, it's only attached to the fiberglass sheeting.

And, if that's the case, then how in the world is it getting any form of a "ground plane" that all (as far as I know) C/B antennas need to operate properly?? Could there be a wire attached to the base of the antenna mount, under the fiberglass sheeting, that ties into the framing someplace to acquire its ground plane? There are no signs of stress cracks or anything like them around that antenna mount. The 2' Firestik has been matched to the radio for a close SWR.

And, since the mounting system, fiberglass only, seems so weak, that's why I choose to use a lower profile, 2' Firestik instead of what might be a higher, more capable antenna like a 4' Firestik. I figure there's quite a bit of stress on that mounting system by wind force alone, much less any low hanging branches etc. in many camp grounds.

Now, please don't suggest I remount the antenna on the side of the coach and rewire my whole C/B system. It's not that important of an item to take on such a remodel. It gets used, but not all that frequently.
Scott

 

[kb7uxe]

if you have your radio tweek and peaked, it is no longer legal to use.
5 watts AM max, 12W PEP on ssb, fixed frequency channelized 1-40. ( 25.965-27.405 )
100% modulation max. blahblahblah..
the steel frame, while not physically attached to your antenna mount, may be RF coupled providing a 50 ohm RF impedance. You range and performance seems correct for what you have and what performance one could expect from a good working system.
Check and see if you can reinforce the mount perhaps by a backing plate to sandwich the mount. Anytime a coil is used to make the radio think it's looking at something it's not, there will always be a trade off. and that trade off will always be performance and convenience. when one gets better, the other gets worse. There is no better antenna than a full 1/4 wave antenna. best ears, widest usable bandwidth, handle lots of power, low noise. however, it's 8 feet tall ( 234 divided by frequency in megahertz = length in feet X 12= inches )
There's no one thing you can do to make a radio/antenna better, but if you pay attention to all the little stuff, you can do pretty good.
Any time a coil is used, usable bandwidth narrows..
So the performance you describe, is what I would expect from a very good working CB system. so other than a wobbly mount, it's right on. You and use a $2 swr meter from a swap, or a spendy timedomainreflectometer tocheck it..
If the ground plane still bother you, you can use the "metal tape" to make a big box with and X in the middle on the inside wall that will work as a good ground plane. This is what fiberglass rigs use, and it works well. But if you swr is good, don't fix it.. it might get worse.

Good luck.
Dan.

 

[FIRE UP]

kb7uxe,
I certainly want to thank you for taking the time to explain the situation to me. Our C/B, as stated, is working. It works perfect for very short distances like say anywhere from 100' to 1000' but, beyond that, it's a hit or miss thing. Sometimes we get real lucky and I can contact a friend at a mile away or more. So, that's it. Now, also as stated, the base of that antenna is mounted in what appears to be, just attached the fiberglass cap of the coach. There's very little support, even for a little short, 2' Firestick. You can see that base move all over the place.

At this point in time, access to that base, from inside the coach, to what I can recall, is impossible. it's very close to a cabinet face frame that's up against the ceiling. And, on one side is the upholsetered ceiling and the other side (inside the forward cabinet, in front of the driver) is another type ceiling. You can't see the base of that antenna. I'd sure like to re-inforce that base though. I don't like things that are "chincy" like that.

But, by the sound of it, and looking at your picture you posted, I'd say you've got just a bit of experience in not only using all this radio stuff but, surely can comment or advise on how and what to do in a certain situation. Thanks again.
Scott

 

[Ramzfan]

Hi Scott, I have been following this thread, as I too am very disappointed in the distance that I get on my 06' Meridian. (Basically, the same coach as yours) I used to get much better range on my other motorhomes with roughly the same setup. I am thinking of installing a new FireStik non-ground plane antenna and the new cable, etc. that goes with it. I will probably talk to a CB shop at the local truck stop and see how much trouble it would be. I am not happy with the 100-1000 foot range that I now experience.

 

[kb7uxe]

If you want lots of range, install a 102" steel whip from the ladder in back, use RG8X coax, 50' run from fron t of rig, up through fridg vent to roof then to back ladder. it will work super !!!
But every time you stop for fuel, it will knock out all the light bulbs in the station canopy !! ( been there done that ) but you will have the best performance possible,...

Fire Up, you'll need to "mc Giever" it.. stailness screws or nut's and bolts to a wood or metal plate to sandwich the fiberglass cap. This will help hold the antenna in place without wallowing out the mounting holes... bad things can happen if you attach the cap to the frame and prevent the movement required.. A short jumper from one of the bolts to the metal frame will do the trick for the ground plane. and remember, just having the metal close by the mount can couple it also. A copper J-pole is an electrical dc short, 0 ohms. however, built correctly, it's an RF 50 ohm load. Same with resistors, a wire wound resistor can be 50 ohms electrical, but as RF increases, it will flood over the loops and become a 0 ohm RF short.
I sure wish you guys were near by, some of this stuff is easy. and I do like to help. You could also see about a lighter antenna with less wind load.

And Ramzfan, over time, the coax connections and antenna connections can oxidize and suffer effects of electrolysis. Just because it's a good mechanical, or electrical connection, does not mean it a good RF connection. Some times the coax will get moisture inside, and have issues. and remember, just because an OHM meter says it's ok, is not an RF test.. and also it is some times power relevant. ( ok at 1 watt, but fails at 5 watts ) bottom line, prolly need to "class -A " the ckt. re-install the connectors and or replace the coax. again, I recommend, RG8X. slightly larger than RG58, but almost as good performance as RG8.. ( the really big stuff) Coax is like a garden soaker hose.. 5 watts goes in, but less come out the other end. and the RG8X is much less "leaky" than RG58.
now my head hurts, time for a nap.. ;-)

 

[kb7uxe]

And i just noticed KI6OND,
Hey, you already know this stuff !!!
and you know adding a linear will only cause trouble in all the onboard computers!
You could convert to through glass antennas.
Thats what I did to eliminate the problem.
bought 2, one for the CB, one for VHF/UHF..
they were cheap.. and work just fine.
Amazon.com: Midland 18-258 40-Channel Glass-Mount CB Antenna: Car Electronics
And with the tuning capacitor in the inside mount,
they will adjust for cb or vhf or just about any frequency you need.
good luck .
Dan.
kb7uxe
73 OM.

 

[DeWat]

That Midland thru-glass antenna ain't inexpensive... cheap... for no reason! And concerning the ground plane, a ground plane is NOT just a connection to or near metal. For a ground plane to work the way it is intended, it must be a grounded metal surface that has a proportionate size to the frequency of the signal (26-27 MHz for C. A ground plane works like a mirror for the signal coming off of the antenna, as the signal hits the ground plane, it reflects upward for that "X" pattern shown in some publications. The only thing I would use on any motorhome that did not have a true metal roof (and not just metal framed) would be a No Ground Plane (NGP) antenna. Finally, elevation is also a critical factor... the higher the antenna, the better the signal. The problem with motorhomes is that you don't have much room to use above the roof line before you start smacking things.

 

[87Rockwood]

I use a High Sierra 500 screw driver antenna mounted on the trailer hitch. I can tune it while driving by listening on my Yaesu, then use a A/B switch to switch in the CB. Good solid ground to frame and vertical clearance for the antenna. On the open road you should get about 5 miles range from the CB. You can use a "phase array" to push the signal front and back but not to the sides for more range. You see them on trucks as two identical antennas, one on each side/mirror.

 

[kb7uxe]

Well, there you have it,
RF is like making soup. there is no right or wrong way.
what works for you, might not work for me..
That's the fun part about radio, YOU get to find out what works best for you.
I've been doing radio for about 40 years,
sent stuff to the ISS and most of the time back,
built stuff that has flown highest and fastest in the world to this day.
so I have a little radio experience .
Radio antennas are a trade off, the trade off will always be performance and convenience.. yes, a through glass CB antenna will not out perform an 8' whip, but it works much better than a 6 inch antenna inside the motor home. ( there's that trade off thing again ) Yes, attaching a lead from the metal antenna mount to the steel frame under the fiberglass RV lid does help for a ground plane. and no,,there is no exact size for a ground plane, although generally if the ground plane is larger than your radiator element, you'll be fine. and last time I checked, my motor home was a bit larger than a cb antenna. So does aluminum tape on the under side of the lid below the antenna mount. it will RF couple through the fiberglass just like "beam" antennas use directors and reflectors that RF couple to reflect and direct your signal. And screw driver antenna are one of the best antennas going to cover extremely wide band width. A 1/4 wave CB signal is about 8 feet long, for vhf about 19 inches, for an 80 meter signal, about 67 feet long !!!and while it's very inconvenient to have a 67 foot antenna on your motor home, a screw driver antenna will work great. cover a very wide frequency range and reasonable performance. but it's still not a 120 foot dipole 85 feet off the ground. ( there's that trade off thing again )
and some what expensive, about $150 used to over $1000 new. And you have to learn to operate it too. So ok, I don't get 7 miles range on my antenna, I only get a mile or 2 on a good day, but it works for what I need. And like I said, if your set up once worked "better" than today, something has changed. simply replace the coax, clean coax connectors, make sure the radio has enough current, and every thing is tight and secure.
Remember , radio is kinda like Occams Razor, it usually works best if it's not made overly difficult by adding complexity, in thought or actions. ..

hey, is that twilight zone music I hear ????