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Message |
    
Georgia235
New member
Username: Georgia235
Post Number: 1
Registered: 3-2005
| | Posted on Tuesday, March 29, 2005 - 9:58 pm: | 
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Hey guys, new member here. I've been into CB's and Export radios for years, but am just now getting back into it.
I've put a Cobra 25 in my truck and am going to run a 3' Wilson Fiberglass for my antenna. What I was wanting to know, are there any major benefits of running a dual antenna setup? I'd put a 3' on the left and right side of the bed of the pickup.
Thanks |
Tech808
Moderator
Username: Tech808
Post Number: 5393
Registered: 8-2002
| | Posted on Wednesday, March 30, 2005 - 12:04 am: |
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Georgia235,
WELCOME TO THE COPER FORUM!
Personally I would suggest a single antenna like a Wilson 1000 Mag mount or Roof mount dead center in the roof and I think you would have much better overall performance.
Just a thought,
Lon
Tech808
CEF808
N9OSN |
Coyote
Intermediate Member
Username: Coyote
Post Number: 176
Registered: 11-2004
| | Posted on Wednesday, March 30, 2005 - 5:56 am: |
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Welcome back to radio. I think I've read enough on here about the proper way to co-phase antennas that unless you can get the antennas 9 feet apart that they cannot be properly co-phased. So I guess I'd suggest a bit taller single antenna mounted in the center of the truck. Of course that's kind of hard to do on a truck. You may want to go with a Wilson mag mount in the center of the cab. |
Hotwire
Intermediate Member
Username: Hotwire
Post Number: 225
Registered: 1-2005
| | Posted on Wednesday, March 30, 2005 - 7:29 am: |
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Daul antennas dont really improve much at all if any. If you want better performance go with a longer antenna and keep it away from the side of the truck. Above the roof as much as possible is what you want. |
Mrbigshot
Member
Username: Mrbigshot
Post Number: 50
Registered: 2-2005
| | Posted on Wednesday, March 30, 2005 - 10:08 am: |
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you would need at least 3 foot above the roof and they need to be 9 foot apart or else you will have a distorted signal |
Skilletlicker
Intermediate Member
Username: Skilletlicker
Post Number: 195
Registered: 5-2002
| | Posted on Wednesday, March 30, 2005 - 2:21 pm: |
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the only benifet of a dual antenna is that the mfg.gets to sell more
the skilletlicker
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Bluegrass
Intermediate Member
Username: Bluegrass
Post Number: 279
Registered: 12-2004
| | Posted on Wednesday, March 30, 2005 - 2:46 pm: |
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Yeah co-phased antennas may look cool but really only work if there at least 100 inches apart so for a pickup i would suggest you get a roof mount antenna.The roof is always a better mounting place then the mirror. |
Racer_x
Intermediate Member
Username: Racer_x
Post Number: 223
Registered: 2-2005
| | Posted on Wednesday, March 30, 2005 - 3:45 pm: |
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Duals can help to even out a directional pattern, but mounting them on your truck bed - especially 3' whips - isn't the best way to go. Mobile antennas work best when they are above all of the metal on the vehicle, and centered over it. |
Hotwire
Intermediate Member
Username: Hotwire
Post Number: 235
Registered: 1-2005
| | Posted on Thursday, March 31, 2005 - 8:08 am: |
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The daul antenna debate is just like the coax length debate. It will continue on forever. |
Keithinatlanta
Advanced Member
Username: Keithinatlanta
Post Number: 560
Registered: 3-2003
| | Posted on Thursday, March 31, 2005 - 8:32 am: |
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Georgia 235, go with a
Wilson 500 or 1000 Magnetic Mount antenna. They work great and very little problem with setting swr's!
Keith in Atlanta
CEF 150 |
Georgia235
New member
Username: Georgia235
Post Number: 2
Registered: 3-2005
| | Posted on Thursday, March 31, 2005 - 2:17 pm: |
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Well, I actually ended up deciding to stay with the Fiberglass antenna setup. I went with a single, 4' Wilson mounted on the forward right side of the bed of the truck. It looks good, just haven't set the SWR yet. I pretty much had to go with fiberglass because of where we park the truck there's about 2 foot of clearance between the top of the truck and the ceiling, so the antenna would be bent all the time, and it would be a pain to back out. As the tips said, it has right about 2/3 of the antenna above the top of the truck.
Thanks for the help and welcome as well, I'll post some pictures soon! |
Racer_x
Intermediate Member
Username: Racer_x
Post Number: 234
Registered: 2-2005
| | Posted on Thursday, March 31, 2005 - 7:02 pm: |
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I don't how there's a debate about duals. On vehicles there really isn't enough space between the antennas to create a very directional pattern. On big trucks it might make the pattern a small oval - but that's about all.
The real benefit on a big rig is that it evens out the radiation pattern. A single antenna mounted on the mirror bracket is very directional because the ground plane for it is off to the side. By using whips on each mirror bracket the pattern is much more omnidirectional.
I've also been told by a local CB shop owner that duals have a bit more bandwidth on a big truck than a single whip does. I've never done an install on a big rig so I can't say from personal experience that it's true, but I'll take his word for it - he's a pretty good guy. |
Snowfire
Member
Username: Snowfire
Post Number: 76
Registered: 2-2004
| | Posted on Thursday, March 31, 2005 - 9:10 pm: |
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I got dual 4' k-40 ant. on my pickup and they work great. Just my info
CEF 294 |
Bigbob
Senior Member
Username: Bigbob
Post Number: 1817
Registered: 12-2001
| | Posted on Friday, April 01, 2005 - 5:29 am: |
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If the first 2 feet(bottom) is in close proximity to metal much of your signal will be lost,without a sophisticated matching network,better to put it on the center of the bed rail,not as good looking but the perfomance will be better,and you can use a co-phaseed set on the back your pattern will be more front to back rather than side-to-side as in the big rig,at 4.5 feet apart you will have an oval pattern front-to-back,closer spacing will be like running one antenna in the middle.So if you want duals,far be it from me to disuade you,do it,besides they look cool,a friend mounted his on the front corners of his hood and put flags on them,real cool.Bigbob |
Rover
Intermediate Member
Username: Rover
Post Number: 148
Registered: 2-2004
| | Posted on Friday, April 01, 2005 - 12:31 pm: |
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Duals. They relieve back pressure in your performance exhaust system? Oops, sorry.  |
Georgia235
New member
Username: Georgia235
Post Number: 3
Registered: 3-2005
| | Posted on Friday, April 08, 2005 - 11:59 am: |
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Just for and update, putting the antenna there just did not work out. I had a constant SWR of over 3 that would not go down. That's with constant adjustment of the tip.
I decided to move it to the left rear corner of the bed of the truck and that worked wonders. That immediately brought it down into the 1.5-2.5 range. So, I'd remembered reading somewhere that some people don't use the ground wire because it affects SWR. So, I unhooked the ground wire from the bracket, and that brought my SWR down to almost nothing! So, I didn't cut the ground wire off, I just cut off the tip and wrapped a tad of electrical tape to keep it from coming in contact with the metal mount and the system works wonders.
I talked 13 miles away yesterday over the white noise on channel 19 while i was just sitting in my front yard, and that's surrounded by trees! Ha ha, I guess I lucked up here.
Thanks for all the help. |
Redwolf_145
Junior Member
Username: Redwolf_145
Post Number: 17
Registered: 4-2005
| | Posted on Sunday, April 10, 2005 - 6:15 am: |
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left rear Corner of the bed that should have made it very directional... |
Outkast
New member
Username: Outkast
Post Number: 3
Registered: 9-2005
| | Posted on Wednesday, September 28, 2005 - 1:14 am: |
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Just to add to the debate, I measured a truck that came into my work the other night, this was a 2000 Peterbilt 379 EXHD and the antennas were only 7'8" apart but I have heard a million times they need to be 9' hmmm anyone know of a bigger truck I could put them on? |
Sg569
Intermediate Member
Username: Sg569
Post Number: 256
Registered: 12-2004
| | Posted on Wednesday, September 28, 2005 - 10:40 am: |
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I belive that the limit on cars and trucks width is about 8 feet, any more and you need special permits to move. Something about road lane width.
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