CB Antenna Debate

Brentbba

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Pretty much finally decided on the Uniden 520. Three times out now w/o any communication and I feel really uncomfortable about it.

Last debate in my mind - which style antenna. I've read, read and read all the posts about cb's and antennas. Down to either the Wilson Lil Wil, Wilson 1000 or a fiberglass mounted to the Kaymar tire carrier where their telescoping light would go.

Benefits of the mag mount - better reception on top of the roof; completely removable when not in use.

Benefit of fiberglass - permanently routed cable; can unscrew the pole when not in use.

Post up your pros and cons. Goal is to have cb and antenna in place by Thanksgiving for the SoCal get together at Anza.
 

alvarorb

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Brent,

I've had all 3 types antenas. All made byu Wilson. By far the best setup was with the Wilson 5000 Magmount. However, my current setup is a fiber glass antenna on my rear bumper. My CB is installed in my dash and I wanted something permanent.

Having said that, I'm planning to move the antenna to the front bumper and use the 5000 antenna instead of the fiber glass one. The 5000 is the way to go. But not on the rear bumper. It's coil resides on the bottom of the unit and most of the engergy would get lost by reflecting from the body of the Cruiser.

Regards

Alvaro
 
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Yep, antenna (any) mounted on the rear tire carrier or front bar won't have a good ground plane, it'll work, don't get me wrong, but it won't be optimal. Go mag mount on top if you don't want to drill.
 

Brentbba

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alvarorb said:
Brent,

I've had all 3 types antenas. All made byu Wilson. By far the best setup was with the Wilson 5000 Magmount. However, my current setup is a fiber glass antenna on my rear bumper. My CB is installed in my dash and I wanted something permanent.

Having said that, I'm planning to move the antenna to the front bumper and use the 5000 antenna instead of the fiber glass one. The 5000 is the way to go. But not on the rear bumper. It's coil resides on the bottom of the unit and most of the engergy would get lost by reflecting from the body of the Cruiser.

Regards

Alvaro
Good to know. Much difference between the 1000 and 5000? Coil size? Lil Wil being even smaller than the 1000?
 

Tools R Us

 
 
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For the longest range communications, debating the finer points of antenna construction maybe worth it, but a 104" whip mounted in the center of the roof will just about always win. For trail caravan type communications just about anything will work. I run a Walmart $9 mag base unit, works good and if a tree knocks it off and I run it over there wont be much :crybaby: :crybaby: .
 
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Absolutely correct Tools R Us. Best world for 11 meter there would be a a 1/4 wave or longer antenna dead electrical center atop the truck.

A rule of thumb is the longer the antenna the better :) but don't quote me on that as I'll get a lot of flack.
 

Mark W

 
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3fj40 said:
Yep, antenna (any) mounted on the rear tire carrier or front bar won't have a good ground plane, it'll work, don't get me wrong, but it won't be optimal. Go mag mount on top if you don't want to drill.

Hmmm... I'm running five different rigs with 102 inch steel whips mounted on the front bumpers. I've got 1.2-1.3 SWR in all of them and better transmit/receive than any of the guys running with me.


Mark...
 

Niner

 
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Quite a few of the Parks that I have attended won't allow antenna's over 48" in length, For safety's sake they don't want the lenght to hit a tree and wip back causing someone watching to loose an eye.
 

honk

 
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All CB antennas are electrically the same length. The coil or the windings on the various types of shorter antennas have the length. The best thing you can do with any antenna is get it as high as possible and in the center of metal mass. Mounted in the center gives more or less equal performance in all directions while mounting fore or aft of center will bias the performance toward the back or front, respectively.
There's another factor usually called loading. That's making the antenna electrically longer in multiples, or part multiples, of the standard 1/4 wave. It can increase performance but depends on design quite a bit.
The best antenna for 11 meters would be a full wave length stainless whip but you won't see it often as that would mean someone driving around with a thirty three foot rod whipping everything around it. Original sidewalk sweeper :)
 

Kofoed

 
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The 5000 can handle up to 5kw of power, and the coil is a little different than the 1000. I doubt that the difference between a 1000 could be discerned at legal power in the field.

Second, while most antennas are electrically 1/4 wavelength long, they DO NOT have the angle of radiation that a true 1/4 vertical has. The angle of radiation for a vertical antenna is important because it tends to direct the transmitted power (and receive) more horizontally--that is toward other cb-er's. Think of the difference between light from a light bulb and that from and a tube on end. Some of the bulbs power is going up into the sky--wasted.

The groundplane every one talks about is really a counterpoise to electrically balance the unbalanced 1/4 wave length, 50 ohm antenna system. Mounting a vertical on the roof helps the horizontal directivity of the signal *very* slightly. It offers a very good counterpoise, though

My vote, given your choices, is the Wilson 1000 mag-mounted to the roof. If you look at the fiberglass antenna, the element is wrapped around the shaft. Think about the angle of radiation analogy I used above
 
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Remember, standing waves aren't the whole story on antenna and RF performance, it's just a matter of how well you've (mis-)matched your impedance. Again, it will work and may perform well, but having a full ground plane underneath that 1/4 wave would make it perform even better.

A good discussion on this is here, albeit it a little lengthy: http://www.k0bg.com/images/pdf/antennas.pdf


P.S.: I end up running a few antennae on my bull bar for convenience alone.
 

Cube Dweller

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Anecdotal feedback: I have a lil' wil and a $10 ebay radio shack cb. On a run this summer when our group was seperated I was the only one in our sub group of 3 that could pick up the radio traffic from the seperated group. CruiserDrew and Dieselbigot were the other two in our subgroup, not sure what radios and antenna's those guys are running.

tony
 

Mark W

 
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Oh yeah, I agree. Middle of the roof of a full size van would be the best location from a radio performance point of view. But, just as the full size van would not work for what I need, the middel of the roof mounting location is less than ideal for me too. The bumper doesn't seem to loose enough perfomance to matter. If I'm putting it on a bumper and not on a bar attached to the bumper, I use a pedestal to raise the base of the anttena up to about headlight height.

Some parks don't like whips? No problem, I don't go to parks. ;)

All the various antennas with the big claims of enhanced peformance compared to whatever competitors they choose to compare to... They are all just attempting to match the perfomance of the plain old 102 inch steel whip.


Mark...
 

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exactly mark, everything out there is trying to be a 102" whip. unfortunatly only a few can or will run that whip so other creations have been made.
i have two, the normal use antenna is a wilson 48" top loaded fiber whip mounted on the front bumper, it works great at medium range. the other is a wilson 5000 that i mount in the same place for when i need to talk much greater distance over bad terrain. i either need to detune my radio or get a 3rd antenna for short range though, i have problems talkin with the guys i wheel with unless we have some distance between us.


kofoed, i think about it this way, the fiber i run is the more direct antenna to other cb'ers, the 5000 is like an umbrella which is why i use it for distance in bad terrain.
 

Mark W

 
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I'm not a real radio guy. I have some hands on experience, but only a layman's knowlege of theory. That said... Sounds like maybe something isn't quite right with your setup??? Overmodulating maybe??? I have Cobra 29s in the rigs I mentioned previously. I can talk to rigs right beside me with no distortion. I have amps in a couple of the rigs. With the output at the 100 watt level I can still talk to the guys in the group nice and clear, as well as reach out for 30 miles. I haven't tested them yet for max range or extremely close operation at the 300 watt setting but I don't expect to see a problem there either.


Mark...
 
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Mark W said:
Hmmm... I'm running five different rigs with 102 inch steel whips mounted on the front bumpers. I've got 1.2-1.3 SWR in all of them and better transmit/receive than any of the guys running with me.


Mark...
I get 1.5 swr plus/minus 1. across the band with. :D Tuned it at Settlers bay at 2 in the morning. Communication is good. :flipoff2:
 

RHINO

 
 
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whats your point loquito?? lower SWR is better so your setup is still not as good as marks :flipoff2: :flipoff2:

yeah mark your right, it sounds like overmodulating or high mic gain. everything seems in order with good SWR and stuff, i think i'm gonna cruise down to the CB shop and let that guru check it out for me.
 
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Hi Rino
I know that the lower number is better, I was more talking to Mark directly.
-S-
 
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Not to belabor the point, but you should test your SWR both at the antenna and at the transmitter itself. A bad feed line or bad ground plane for the antenna can counteract each other and erroneously produce low SWR when read at the radio only. Ensure you check both spots.

SWR is just a measure of how well the impedance matches: if the feed line (coax) and antenna are both off you can still get an good impedance match at the meter; but continue to loose radiating power through the system.
 
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