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Author Topic: mounting 102 inch stainless steel whip on truck bedside  (Read 4734 times)
KC0YEW
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« on: April 07, 2013, 05:51:53 PM »

I am having difficulty with my 102 inch stainless steel whip grounding out after a short time driving...the center conductor which actually carries the current is adjusting itself in the mount hole and shorting.  My difficulty is my 1997 chevy s10 pickup's bedside is made with two layers of steel instead of being one layer thick.  I have tried wrapping some bicycle inner tube followed by electrical tape, but in the installation the inner tube is being damaged, is there some sort of hard plastic insert to go in the hole to keep this from happening?
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AC5UP
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« Reply #1 on: April 07, 2013, 06:57:17 PM »

Do you have a ball mount at the base of the antenna?  http://www.radioshack.com/product/index.jsp?productId=2062088

If not, you'll either need to fabricate a mounting plate with a 3/8" nylon bushing and matching washers or get a ball mount at DuhShack.

That's how CHP mounted radio whips on their cruisers and if that was good enough for Broderick Crawford then it's damn sure good enough for............
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KC0YEW
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« Reply #2 on: April 07, 2013, 07:00:48 PM »

no, i wasnt using a ball mount, i bought the antenna at radioshack and installed it with the basic hardware that came with it.  i have no actual mount, i was attempting to use the bed side itself as the mounting bracket as the antenna came with a simple flat plastic washer to keep the top portion of the antenna from grounding out.  A ball mount itself  doesnt really have a flat spot to be mounted to.  My truck has a very curvy bedside as it's a sport edition. 

http://www.stu-offroad.com/cb/cb_install-3.htm
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KE3WD
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« Reply #3 on: April 08, 2013, 05:34:03 AM »

There are right abgle mounts made that are smaller than the good old ball mount design.  IMO you should use the ball mount.  Ball mount with spring is even better.  Much sturdier. 

http://www.ebay.com/sch/sis.html?_nkw=3-8-x-24-Right-Angle-Antenna-Stud-Mount-CB-Ham-Radio-

While the angle mounts designed for clamping to truck mirrors can be adapted to the side of pickup truck bed, using the same four bolts as the clamp, the moment angle of the 102" whip on a moving vehicle can wear and tear over time.  But is possible. 

There are steel angle mounts available for use on side of truck, or one can be fabricated to suit as well. 

One nice thing about using the ball mount is that you can rather easily remove the whip by unscrewing from ball, can also quite easily put something shorter in its place, such as the loaded fiberglass single band sticks as well. 

Attempts to fabricate your own mount can be done, but would likely have to incorporate use of machine shop techniques and Delrin or Nylon to fabricate proper hard insulated bushings.  Not advisable for someone trying to utilize inner tube rubber there, though, and certainly not affordable to go that route when the ball mount design currently available is inexpensive, time proven for decades and easy to make work right. 

73
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AD6KA
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« Reply #4 on: April 08, 2013, 11:23:56 AM »

Would this stake bed antenna mount work with your truck?
http://www.shopjubilee.net/itm00547.htm
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WA3SKN
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« Reply #5 on: April 08, 2013, 03:15:38 PM »

Rubber is a poor insulator at RF.  It appears you need a better mount for the 102 inch whip.  I think Hustler makes the best ball mount, but it is expensive solid stainless steel.  I am sure there are others on the market that will work for you.
Time to check out what the market now offers!
73s.

-Mike.
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KC0YEW
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« Reply #6 on: April 09, 2013, 12:20:55 PM »

i am supposing i will pick up a ball mount for mounting this as it seems like the best option at the moment.  I did manage to make it work and i no longer have direct  continuity between the antenna, but my vom is showing me about 1600 ohms of resistance between the driven element and the truck body.  i tested it yesterday and there was no continuity and no resistance between the truck body so i tried to work a dx station, it seems like the signal just is not getting out so i am worried that the cab of the truck is absorbing the rf, i am going to move the antenna back by the wheel well a bit more, i just hope i have enough room to install the ball on the bed rail.  My bed rail is not exactly flat, so my polarization is going to be slightly off from vertical by just a touch.  Pocket stake install is not possible as my truck has no pockets to put the stake in unfortunately.    This is an image of what my truck looks like...looked like 5 years ago before the rust started eating the cab corners and the fenders.   http://www.smartcarguide.com/listimg/img1_0214/01/img_3G13K63Lb5L15F35M9d17fe385021ff0c16e6.jpg
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KE3WD
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« Reply #7 on: April 09, 2013, 12:27:37 PM »

Your sig will still be vertically polarized with tilted antenna base, so no worry there. 


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K8AXW
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« Reply #8 on: April 09, 2013, 10:02:18 PM »

Whenever you mount an antenna of any kind on a vehicle; where you mount it determines the radiation pattern of the signal.

The signal is radiated in the direction of the greatest mass of metal which is in reality the other half of the antenna.

So if you're antenna has a low SWR but you're finding it difficult working some stations, pay attention to the direction the "greatest mass of metal" is pointing.

Antennas mounted at a vehicle "corner" will radiate in a diagonal direction.  If the antenna is centered in the middle of the vehicle, then it radiates pretty much in all directions.

Tractor-trailers use phased vertical antennas (one on each mirror) to provide a radiation pattern that has major lobes going forward and rearward.  (A figure 8 pattern)

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KD8GEH
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« Reply #9 on: April 10, 2013, 01:34:31 PM »

My 2 cents  Grin

For a 102 in whip you really need the HD mount, better yet the mount with HD spring. The antenna naturally vibrates, esp the fiberglass ones hihi. This tends to loosen the mount bolt on longer antennas.  A 4 foot whip is usually fine with the thru hole mount.

Been there done that...

73 and have fun!

Dave KD8GEH
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KC0YEW
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« Reply #10 on: April 10, 2013, 01:39:38 PM »

i agree, i probably need to move the antenna back a bit as it may be too close to the passenger cab corner, that's no big deal, i'll put it over the fender well and i will definately use the spring as it is already mounted with the spring i just hope the ball mount is narrow enough to sit on the bed rail. 
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KE3WD
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« Reply #11 on: April 10, 2013, 02:36:41 PM »

If you bed has stake holes, consider the Stake Mount and ball. 

With that, no holes are drilled in the bed, an added attraction IMO. 

You could also experiment by moving it to other stake holes rather easily, find out about the patterns you've been told about here.


73
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KC0YEW
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« Reply #12 on: April 10, 2013, 07:32:55 PM »

negative my truck has absolutely no stake holes
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W6EM
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« Reply #13 on: April 11, 2013, 03:54:21 PM »

negative my truck has absolutely no stake holes
I used to have a ball mounted 10M antenna mounted on a Dodge Dakota.  I made a large, 5/16 aluminum angle bracket and mounted a ball to it.  The bracket I bolted to the frame behind the driverside rear fender well.

An easier approach, if you have a hitch receiver, would be to buy one of the hitch mounts for the ball.  Some of those put the ball in the center of the bumper, while some are offset to the left or right.

The other problem with thin insulation bushings are that when they get wet, they will short out the antenna and will retain moisture.  The ball mount, regardless of whether it's from the Shack, Hustler, or (the best) /\/\otorola surplus from the CHP.......  :-)
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KB3HG
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« Reply #14 on: April 14, 2013, 07:02:10 PM »

Double wall , even if you were able to tighten your mount per your diagram the torque exerted on the body would bend sheet metal.
Suggest you look at www.K0BG.com . Al has a great site lots of information.
The larger the base the less deflection of sheet metal.

73,
Tom Kb3hg
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