ghamblen
Wilder, ID
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This is what I did with mine about two weeks ago. I used a 42 inch battery interconnect cable to ground the rear ladder to the frame extensions. I mounted the 4 ft. Firestik antenna to the ladder using a 3-way mount. Approximately 3 ft. of the antenna is above the roof. I then ran a 45 ft. RG-58A cable from the antenna up to the dash area in front of the driver's seat. I mounted the Cobra 75 interface box under the dash and the CB/microphone unit on the dash just to left of the doghouse. I then checked the antenna SWR with a meter and got 1.6 on channel 1 and 1.7 on channel 40. I decided that was good enough. I could hear communications on the weather channels but could not hear any truckers on channel 19 at the time. On a trip into the mountains the next weekend we could hear the weather channels everywhere we went. The CB channels seem to have a range of about 5 miles. Overall I am happy with the results.
Gary & Mary Hamblen
2006 Gulfstream Ultra LE 6316
2006 Saturn VUE
Roadmaster Sterling tow bar with US Gear Unified tow brake
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fisher60
Plant City, Florida
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I used a hood/fender mount and 48" fiberglass stick, but you need a stiff stick so it doesn't slap the cab-over while driving. Mine works great.
'01 Dutchman Express 28A, Master Tow, '06 Tuscon, '05 Honda VTX 1300
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Bumpyroad
Virginia
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jbbrick wrote:I put in one of the thru-the-glass types on the side window of the upper bunk. Not the greatest reception I think, but it works fine for cumunication between two rv's when traveling. And, no holes thru the wall or roof. Your other option is a pair of the mirror antennas.
If you have dual pain windows,
"don't try this at home". 
don't ask me how I know.
bumpy
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KEBrown
Kansas
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If the ladder is aluminum can it be considered grounded (if a ground wire is ran from the frame to the ladder). I have LOTS of cable and can run it all the way to the cab. Being 3-4 feet above the roof line may present problems as the coach is already 11'4" tall, not including the a/c. Really don't want to go to 13+' for fear of bridges, etc. I might try the "unicorn" magnetic mount on the hood for the short-term and play with different mounting locations. I don't mind the mirror mounts either, that would be simple, but I'd probably stick with just one on the drivers side; would that be acceptable?
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Dusty R
Charlotte Michigan 48813
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Some how my message with pictures got lost. It's there when I hit edit.
* This post was
edited 09/01/09 07:38am by Dusty R *
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Cloots6
Avon Lake, OH
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Joined: 12/21/2005
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The "Unlimited AUVAN" mount that screws into the fender between hood and fender using existing screw from fender, and a 48" no ground plane (NGP) antennna - works great.
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ghamblen
Wilder, ID
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KEBrown wrote:If the ladder is aluminum can it be considered grounded (if a ground wire is ran from the frame to the ladder). I have LOTS of cable and can run it all the way to the cab. Being 3-4 feet above the roof line may present problems as the coach is already 11'4" tall, not including the a/c. Really don't want to go to 13+' for fear of bridges, etc. I might try the "unicorn" magnetic mount on the hood for the short-term and play with different mounting locations. I don't mind the mirror mounts either, that would be simple, but I'd probably stick with just one on the drivers side; would that be acceptable?
I think either way will work just fine. Aluminum is a good conductor and they used to use it to wire houses. Then they found out it causes a fire hazard when it corrodes so it has been banned for this use. When I gounded my ladder I used an ohmmeter to check continuity from the top of the ladder to the frame extension. It read zero ohms so that is about as grounded as you can get.
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Bumpyroad
Virginia
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ghamblen wrote:
I think either way will work just fine. Aluminum is a good conductor and they used to use it to wire houses. Then they found out it causes a fire hazard when it corrodes so it has been banned for this use. When I gounded my ladder I used an ohmmeter to check continuity from the top of the ladder to the frame extension. It read zero ohms so that is about as grounded as you can get.
I thought the problem was in corrosion and a difference in expansion between it and copper screws, etc. causing a heating up and finally a fire hazard.
bumpy
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ghamblen
Wilder, ID
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Bumpyroad wrote:ghamblen wrote:
I think either way will work just fine. Aluminum is a good conductor and they used to use it to wire houses. Then they found out it causes a fire hazard when it corrodes so it has been banned for this use. When I gounded my ladder I used an ohmmeter to check continuity from the top of the ladder to the frame extension. It read zero ohms so that is about as grounded as you can get.
I thought the problem was in corrosion and a difference in expansion between it and copper screws, etc. causing a heating up and finally a fire hazard.
bumpy
You are right Bumpy. The corrosion caused heat build up and then the difference in coefficient of expansions reared its ugly head and things went downhill from there. My uncle had a house wired with aluminum wire and there are fixes for it but its not cheap. He finally got it all fixed but his wallet was considerably lighter. That brings up another thought. I wonder if any RVs were wired with aluminum wire.
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klhutch
Sububan Chicago
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ghamblen wrote:When I gounded my ladder I used an ohmmeter to check continuity from the top of the ladder to the frame extension. It read zero ohms so that is about as grounded as you can get.
Actually it is not as grounded as you can get or at least your Ohmmeter is unable to tell you whether it is or not. Your Ohmmeter uses a DC current to measure the resistance of your connection. It gives you a valid reading for DC and for AC power wiring at 50/60 Hz. But the resistance your 27 MHz CB transmitter sees will be higher because something called the "skin effect" causes the current at those frequencies to flow only on the outer surface of condutors and that makes the effective area or "gage" of any wire or conductor far different from its physical dimensions. In addition wires will have significant inductance at these frequencies which further complicates the picture.
In fact it is a simplification to believe that the vehicle chassis itself is "ground". In reality the whole metal structure of your MH becomes part of the antenna. The results you get can vary quite a bit depending on where and how your ladder (to stick with the current example) is connected to the rest of the chassis. I am not saying this to prove that you are wrong or to discourage people from using the ladder as a "ground" for their CB antenna. I am just pointing it out so that people will understand that if their ladder mounted antenna needs more tuning than another person reports or gives better or worse results it is because the situation is quite complex and variations in results are to be expected.
The situation is not hopeless, it seems like most people do get good results from ladder mounted antennas. Analyzing the situation for any given MH is a daunting task that most radio engineers would struggle with. So we MH owners tend to use the experience of others as a guide instead of attempting to calculate an optimum installation approach for our own MH. Any of the techniques mentioned here will likely give you similar results, just understand that because of vehicle variations your results will vary and an antenna placement that works very well for some can turn out to be poor for others. That just means that if one doesn't work you should try another.
Ken
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