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Message |
    
Gundog
New member
Username: Gundog
Post Number: 9
Registered: 1-2005
| | Posted on Thursday, January 27, 2005 - 9:06 pm: | 
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i am runnig a steel whip on the drivers rear bed stake on a full size pickup.is this the best location, what length coax is good for swr? and i dont really want to run a spring. any tricks of the trade would be great.peace |
Cbblackbeard
Intermediate Member
Username: Cbblackbeard
Post Number: 154
Registered: 12-2003
| | Posted on Thursday, January 27, 2005 - 11:38 pm: |
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If I'm not mistaken, you should always run 18' of coax in a mobile instalation. You may also NEED to use a spring to get the best SWR. Most people that I know who use a 102" whip had to use a spring to get the SWR down. As for location... the best location is always in the center of the roof, which may not be so easy to do with 102" of whip. I'm happy you posted this question because I want to try a 102" whip also, and am looking for advice. I'm thinking about mounting mine on the left hand corner of the rear bumper. |
Doc_kilowatt
New member
Username: Doc_kilowatt
Post Number: 1
Registered: 1-2005
| | Posted on Friday, January 28, 2005 - 12:09 am: |
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21' of coax while running a 102" atop a 6" spring. Thats the best formula I have come up with over the years, and if i must use jumpers they are kept short at 3' if possible |
1861
Junior Member
Username: 1861
Post Number: 47
Registered: 2-2004
| | Posted on Friday, January 28, 2005 - 8:29 am: |
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I USE 18 FT MINI 8 WITH 3 FT JUMPER TO AMP . INSTEAD OF SPRING , I GOT A PIECE OF ALL THREAD 8 INCH LONG . MOUNTED ON BACK BUMPER , MY SWR IS PRETTY WELL FLAT THROUGH OUT THE BAND |
Racer X (Unregistered Guest)
Unregistered guest
| | Posted on Friday, January 28, 2005 - 6:08 pm: |
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Use the shortest length you need to make it from the antenna to the radio. If you want to read an accurate VSWR at the radio end, then it needs to be a 1/2 wave multiple in length.
To find that length divide 492 by the frequency in MHz to get the freespace 1/2 wave length in feet, then multiple by the velocity factor of the coax used to get the physical length in feet.
I wouldn't bother with trimming the coax to try to read the VSWR at the radio with a 102" whip. It'll be good unless you have other CB antennas on your vehicle or it's mounted where there is a large piece of metal above it's feed point. |
Cbblackbeard
Intermediate Member
Username: Cbblackbeard
Post Number: 156
Registered: 12-2003
| | Posted on Saturday, January 29, 2005 - 3:22 pm: |
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1861,
How does your 102" whip perform being mounted on the back bumper? How is it mounted? With a stud or some kind of bracket? |
1861
Junior Member
Username: 1861
Post Number: 49
Registered: 2-2004
| | Posted on Saturday, January 29, 2005 - 4:32 pm: |
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IT WORKS GREAT , I HAVE A SMALL CAR . I MADE A PLATE THAT BOLTS TO FRAME WORK RIGHT AT BUMPER AND STICKS OUT FROM UNDER BUMPER . DRILLED THIS PLATE FOR SS 102 . WORKS ALOT BETTER ON DX THAN MY WILSON 1000 MAG MOUNT |
1861
Member
Username: 1861
Post Number: 50
Registered: 2-2004
| | Posted on Saturday, January 29, 2005 - 4:33 pm: |
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IT WORKS GREAT , I HAVE A SMALL CAR . I MADE A PLATE THAT BOLTS TO FRAME WORK RIGHT AT BUMPER AND STICKS OUT FROM UNDER BUMPER . DRILLED THIS PLATE FOR SS 102 . WORKS ALOT BETTER ON DX THAN MY WILSON 1000 MAG MOUNT |
Kid_vicious
Intermediate Member
Username: Kid_vicious
Post Number: 187
Registered: 9-2004
| | Posted on Saturday, January 29, 2005 - 5:02 pm: |
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AAAAHHHHHHHH!!!!!! when will we finally put these silly coax notions to reast?!
if you mount that 102" whip properly, whatever length of coax you use will work just fine.
i am not a fan of mounting anything to the bumper, but if it works i guess thats good enough. i mounted mine to the side of my pickup bed tool box which is bolted to the body. i have a 1.5 to 1 swr or better from 26.5 to 28.5.
the bed rail is a fine place to mount your antenna, just make sure its grounded well, (no paint). 102" whips are designed to operate with the spring, i dont know why you wouldnt want to run one. if youre worried about the extra flex, let me tell you this. when i am driving 80 mph, (only to pass of course!) my whip bends like a fishing pole but the spring stays tight. use the heavy duty spring and you'll love the results. BTW, point your truck at the direction you wish to talk to because your set up will be directional favoring the front of the vehicle.
matt |
Sg569
Member
Username: Sg569
Post Number: 72
Registered: 12-2004
| | Posted on Monday, January 31, 2005 - 4:22 pm: |
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Personally I don't use the spring, I have a 102ss on the driver's rear bumper, '85 toy p/u, 19 feet of coax( rg8 none of that small stuff), and had a flat 1 match. I used one of those rat shak mounts( drill 1/2" hole... screw coax to mount... attach ant...) works good |
Cbblackbeard
Intermediate Member
Username: Cbblackbeard
Post Number: 158
Registered: 12-2003
| | Posted on Monday, January 31, 2005 - 11:32 pm: |
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I mounted the 102" on my bumper tonight using the same method that SG569 used. The only difference is that I used the spring. I need to buy new coax and hook that up and check swr. Hopefully I'll get off work early enough tomorrow to do that. |
Hotwire
Junior Member
Username: Hotwire
Post Number: 19
Registered: 1-2005
| | Posted on Tuesday, February 01, 2005 - 12:31 pm: |
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I too use ss102inch whips. I had one on my trunk lid, reinforced of course and it worked great. I now use a little shorter 96 inch fiberglass.Get a better swr with it. So has anyone tried the 96 inch whip from Francis? They call it a true triple qaurter wave whip. I can see three little copper wires at the tip! neato I must say |
Cbblackbeard
Intermediate Member
Username: Cbblackbeard
Post Number: 159
Registered: 12-2003
| | Posted on Wednesday, February 02, 2005 - 12:17 am: |
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I hooked up my brand new coax tonight and on the analyzer I'm getting a 1.4 swr across the band. On the radio's meter it looks a little lower. |
