CB Radio Antenna Mount
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dancojgl
New member
Things to keep in mind regarding any two-way radio antenna:
1. 1/4-wave antennas need a ground plane (the ground plane "reflection" fools the transmission line (coax) into thinking it's impedance-matched to a 50-ohm 1/2-wave dipole).
2. The best all-around (omnidirectional) radiation pattern is obtained with the antenna in the center of the roof.
3. Mirror-mount antennas intensify the radiation pattern to the front and rear of the vehicle, but are only effective if two are mounted 1/4-wavelength (9 feet for 27MHz CB) apart.
You see them often on trucks, which can get the 9 foot spacing, but they don't work on cars or SUVs. On cars, where the spacing is less than 1/4-wavelength, the radiation pattern is actually shortened front and rear and decreases your range for talking with other CBers on the road.
4. A 1/4-wave antenna mounted in the bumper area with a mirror mount will have a poor, if any, ground plane. The radiation pattern will be extremely short to the sides and rear of the vehicle, with a higher "lobe" toward the front.
5. A 1/2-wave antenna mounted in the bumper area with a mirror mount will be fairly omnidirectional (1/2-wave antennas need no ground plane), but the signal toward the front will be slightly attenuated by the vehicle's metal body.
The general rule-of-thumb is to use a ground-plane antenna system wherever possible. This means a roof-mount antenna in the middle of the roof.
If you are leery of punching a hole in the roof and routing the coax cable in the headliner, I would suggest a magnetic-mount antenna. These actually work quite well, don't require any holes, and can be stored inside the vehicle to prevent theft.
{Edit} If you go with a magnetic-mount antenna, be sure to move it around once in a while, to give the paint on the roof a chance to age evenly...
More in-depth info can be obtained at http://www.firestik.com/Tech_Docs.htm
1. 1/4-wave antennas need a ground plane (the ground plane "reflection" fools the transmission line (coax) into thinking it's impedance-matched to a 50-ohm 1/2-wave dipole).
2. The best all-around (omnidirectional) radiation pattern is obtained with the antenna in the center of the roof.
3. Mirror-mount antennas intensify the radiation pattern to the front and rear of the vehicle, but are only effective if two are mounted 1/4-wavelength (9 feet for 27MHz CB) apart.
You see them often on trucks, which can get the 9 foot spacing, but they don't work on cars or SUVs. On cars, where the spacing is less than 1/4-wavelength, the radiation pattern is actually shortened front and rear and decreases your range for talking with other CBers on the road.
4. A 1/4-wave antenna mounted in the bumper area with a mirror mount will have a poor, if any, ground plane. The radiation pattern will be extremely short to the sides and rear of the vehicle, with a higher "lobe" toward the front.
5. A 1/2-wave antenna mounted in the bumper area with a mirror mount will be fairly omnidirectional (1/2-wave antennas need no ground plane), but the signal toward the front will be slightly attenuated by the vehicle's metal body.
The general rule-of-thumb is to use a ground-plane antenna system wherever possible. This means a roof-mount antenna in the middle of the roof.
If you are leery of punching a hole in the roof and routing the coax cable in the headliner, I would suggest a magnetic-mount antenna. These actually work quite well, don't require any holes, and can be stored inside the vehicle to prevent theft.
{Edit} If you go with a magnetic-mount antenna, be sure to move it around once in a while, to give the paint on the roof a chance to age evenly...
More in-depth info can be obtained at http://www.firestik.com/Tech_Docs.htm
Last edited:
MrTom
Member
Am using a magnetic mount in the center of the roof for both CB and Ham , with very good results. I put the magnet in a heavy duty plastic ziplock to protect the roof from scratches and the mast to magnet connection from rain. Can also use just a square sheet from a baggie under the magnet if good weather.
Tom
Tom
Good Times
New member
Mount it on your bumper (the rear if you have a place - if it's not stock..., if not the front then...)
Reason: If you drill into your front fender like me... eventually it'll tear apart while you're offroading... (not a pretty sight). Mine is currently mounted on the fender and it'll be moved to the rear bumper next week.... (fender mount starting show fatigue.... lots of excessive movement)
I suggest you stayin away from the fender area completely since I know you do quite abit of offroading
Hope to see ya soon on the trails!!
Reason: If you drill into your front fender like me... eventually it'll tear apart while you're offroading... (not a pretty sight). Mine is currently mounted on the fender and it'll be moved to the rear bumper next week.... (fender mount starting show fatigue.... lots of excessive movement)
I suggest you stayin away from the fender area completely since I know you do quite abit of offroading
Hope to see ya soon on the trails!!
yabedude
New member
Pics of how I mounted CB Antenna to 4th Gen.
http://f1.pg.photos.yahoo.com/ph/yabedude/album?.tok=phb.DoABmO5OEOLp&.dir=/fdfa&.src=ph
I chose this setup because the antenna could be easily removed. I also have to give credit to another 4Runner owner as I cloned his antenna mount concept:
http://www.hboss.net/4runner/cb_install.htm
http://f1.pg.photos.yahoo.com/ph/yabedude/album?.tok=phb.DoABmO5OEOLp&.dir=/fdfa&.src=ph
I chose this setup because the antenna could be easily removed. I also have to give credit to another 4Runner owner as I cloned his antenna mount concept:
http://www.hboss.net/4runner/cb_install.htm
yabedude
New member
I don't leave the CB antenna on unless I'm on a trip somewhere, so a chrome cap covers the NMO mount most times.
Hope these pics help. Later today, I'll take some pics on the HAM antenna and where I mounted both radios in the cabin. Hint ... HAM radio is not visible and CB is removable.
Hope these pics help. Later today, I'll take some pics on the HAM antenna and where I mounted both radios in the cabin. Hint ... HAM radio is not visible and CB is removable.
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flownosaj
New member
Yabedude--with your hood mount, how is the reception compared to a magnetic roof mount? Do you notice any decreased loss of signal?
I'm thinking that the hood mount may be the next best option to the magnetic roof mount. With the hood mount, I won't have to re-tune it each time I attach the antenna once I have it dialed in.
I'm thinking that the hood mount may be the next best option to the magnetic roof mount. With the hood mount, I won't have to re-tune it each time I attach the antenna once I have it dialed in.
yabedude
New member
flownosaj said:
I never considered a magnet mount. Magnets tend to get pulled off by branches plus scratch the paint. I've not had any problem with reception nor transmission. Don't skimp on the antenna and you won't have a problem. Obviously, you have to make sure that the mount is properly grounded. I used the existing fender screw that is close to center of the fender.
I never got around to taking new pics of the other antenna, but here's a sample of one I found from a trip in August.
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fourwd1
Moderator
dancojgl said:
Ground plane = a METAL surface area, the bigger the better
The ground plane is a necessary part of the antenna, the 2nd half of the antenna, it's not "fooling' anything.
And require a special harness.
They're a waste of $
Magnet mounts DO work.
I run 3 mag mnt antennas on the roof of my Trooper (2M, 6M, 10M ham bands) and they work just fine.
Just get a good one, such as the K40 or Wilson.
Another antenna fact, a basic 1/4 wave length whip at CB frequency (27MHz) is 108" long. Antennas made physically shorter by loading coils become inefficient. The shorter the antenna, the more inefficient. If you're not looking for great range, than it's fine.
Even better in-depth info can be obtained at , and it's not biased like the Firestick site (after all, they SELL antennas)
4RunnerKid
New member
Here's how a I mounted mine...
driffter33
New member
Here is a link to a current thread about the subject.
http://www.toyota-4runner.org/3rd-gen-t4rs/80673-cb-ant-mount.html
http://www.toyota-4runner.org/3rd-gen-t4rs/80673-cb-ant-mount.html
4runner_2006
New member
looks sweet, pm sent
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