Antenna

Topic: Antenna (Read 967 times) previous topic - next topic

Antenna

July 19, 2011, 10:11:56 am

There is a antenna base above the driver. Base only. It doesn't appear to be broken, just missing the whip. Is that the CB or Radio antenna? Anyone replaced theirs?

Re: Antenna

Reply #1 – July 19, 2011, 10:35:45 am

The ball mount? Yep, that is where mine is. The other side of it should be in the compartment above and left of drivers seat. I had to replace mine. Brought a new ball mount and spring. And a Firestik No Ground Plane 3 foot antenna w/matching NGP coax. The No Ground Plane antennas are designed for use in a vehicle that lacks a metal roof that would act as a ground plane for the antenna. Lack of a metal roof is not a perfect situtation for a transmitting antenna and the NGP antenna is a compromise.

Re: Antenna

Reply #2 – July 19, 2011, 11:05:35 am

Thanks. Does the coax screw off the ball mount? What brand ball did you purchase. Noticed you have a Fusion. Did you wire to the car lights or add bulbs? Did you install the base plates or have it done?

Re: Antenna

Reply #3 – July 19, 2011, 11:16:45 am

I misread your signature. It says Focus instead of Fusion.

Re: Antenna

Reply #4 – July 19, 2011, 02:00:57 pm

I replaced both AM/FM and CB Antennae.

I removed the entire mount so had a hole in the roof, then used the base which was on the roof and adapted the antennae mounts to it so that holes in roof were sealed.

The aluminum frame in the roof makes a very good ground plane for the CB antennae and will provide better CB performance than a NGP antennae, which are normally used on fiberglass boats. Ground wire must be short with good contact to aluminum . Sand aluminum and immediately connect ground wire and seal with grease. Aluminum oxide is an insolator and it begans forming immediately.

AM/FM antenna must be 7 or more feet from CB antenna or it will interfer with CB antenna tuning. The AM/FM and CB antennae on my 1996 U320 were only one foot apart, so I moved the CB antenna to the passenger side roof and fixed the hole in the roof.

Re: Antenna

Reply #5 – July 19, 2011, 05:10:21 pm

Quote from: P. Wyatt Sabourin – July 19, 2011, 02:00:57 pm

I replaced both AM/FM and CB Antennae.

I removed the entire mount so had a hole in the roof, then used the base which was on the roof and adapted the antennae mounts to it so that holes in roof were sealed.

The aluminum frame in the roof makes a very good ground plane for the CB antennae and will provide better CB performance than a NGP antennae, which are normally used on fiberglass boats. Ground wire must be short with good contact to aluminum . Sand aluminum and immediately connect ground wire and seal with grease. Aluminum oxide is an insolator and it begans forming immediately.

AM/FM antenna must be 7 or more feet from CB antenna or it will interfer with CB antenna tuning. The AM/FM and CB antennae on my 1996 U320 were only one foot apart, so I moved the CB antenna to the passenger side roof and fixed the hole in the roof.

Wyatt, I am curious about a couple of things. I am certainly no expert on radio physics but I always thought for best performance the antenna had to be in the center of the metal ground plane. If the antenna is on one side of the vehicle, it pretty much makes it a directional antenna with very little signal on the side where there is no metal and the maximum signal on the side where there is the most metal. Is the not correct?

Also, do you know anything about cellular antennas? I have purchased the Wilson dual band Truckers antenna that has six small radial rods for its ground plane but so far I am not terribly impressed. I currently have mine mounted to air horn about 16 inches from the AM/FM antenna. Does this configuration sound like a problem? Any tips would be appreciated.

Re: Antenna

Reply #6 – July 19, 2011, 11:56:28 pm

Quote from: Jerry & Coleen – July 19, 2011, 11:05:35 am

Thanks. Does the coax screw off the ball mount? What brand ball did you purchase. Noticed you have a Fusion. Did you wire to the car lights or add bulbs? Did you install the base plates or have it done?

I went Firestick all the way. The coax is already set up to screw on. Fusion is just a bit bigger that the Focus. I installed a set of Turn Stop Tail LEDs on the back rear window ledge. They are set up to work with the motorhome only. Did not want to tie into the toad wiring until the warranty is up. I don't think there is room to add bulbs in the light housing, but would like to. Will have to investigate that some one of these days.

Re: Antenna

Reply #7 – July 20, 2011, 02:10:54 pm

Cellular antenna tuning I know little about. The frequency of cellular is way higher than frequency of AM/FM/CB. The length of AM/FM and CB antennae are similar while cellular antennae are much shorter. My guess, and it is only a guess, is that the AM/FM antenna will have much less effect on cellular then on CB.

CB Ground Plane Theory:
The transmitted signal from a CB antenna which has no ground plane will radiate in all directions evenly (even to space). The ground plane distorts the radiated signal and reduces the amount of signal going to space while increasing the amount going parallel to the ground plane. If transmitting horizontally in all directions evenly is desireable, then placing the antenna in the center of a horizontal ground plane is desireable. When driving a vehicle, it is often desireable to have more signal horizontally straight ahead or straight back, because that is where the highway goes (sometimes). The most important effect of the CB ground plane is to increase the amount of signal going horizontal by decreasing the amount going into space. The most important positioning for a CB antenna is high and clear of obstructions. Centered on the roof is of less importance.

I see CB antennae mounted on the side of the motorhome, however, this shields the antenna and reduces it's effectiveness. I always mount a long stainless whip (Larsen or K40) on top of the roof, as far behind the windshield as possible, and such that the top is just under the 14.5 foot height limit in Canada. A stainless whip will survive a tree branch hit which may damage a spring mounted firestick.

CB Antenna maintenance is very important. Every year I check the SWR reading of my CB antenna and usually find that I need to re-establish good ground contact, good antenna/coax contact, and polish the antenna to reduce static.

Foretravel Owners' Forum For owners and Fans of Foretravel Motorcoaches September 11, 2025 ...

Antenna

July 19, 2011, 10:11:56 am

Re: Antenna

Reply #1 – July 19, 2011, 10:35:45 am

Re: Antenna

Reply #2 – July 19, 2011, 11:05:35 am

Re: Antenna

Reply #3 – July 19, 2011, 11:16:45 am

Re: Antenna

Reply #4 – July 19, 2011, 02:00:57 pm

Re: Antenna

Reply #5 – July 19, 2011, 05:10:21 pm

Re: Antenna

Reply #6 – July 19, 2011, 11:56:28 pm

Re: Antenna

Reply #7 – July 20, 2011, 02:10:54 pm

Affiliate Notice