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ANOTHER VARIATION OF THE J-POLE..THE SLIM JIM_KIMMEL

 
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ANOTHER VARIATION OF THE J-POLE..THE SLIM JIM_KIMMEL
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Black_Hawk
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Compulsive poster:)


Joined: 15 Mar 2004
Posts: 112
Location: Entering The Flags...but simply an arm wielding a sword signifying power

Post ANOTHER VARIATION OF THE J-POLE..THE SLIM JIM_KIMMEL Reply with quote


Hey you car thieves out there..Dont let the name lead you folks astray..and no it was not Dzined by Jimmy Kimmel and Saul either..However i heard thru the grapevine that Saul was into Car Jacking out in LA when he was a Young Punkster
Sat May 29, 2004 7:26 am View user's profile Send private message
Black_Hawk
Compulsive poster:)
Compulsive poster:)


Joined: 15 Mar 2004
Posts: 112
Location: Entering The Flags...but simply an arm wielding a sword signifying power

Post ANOTHER VARIATION OF THE J POLE DZINE courtesy Jimmy Kimmel Reply with quote


The Cautionary notes apply..not rekommended to be used in Car Jackings
Sat May 29, 2004 7:32 am View user's profile Send private message
Doc
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Post The world's best 15 dollar antenna. The Desert Slim Jim Reply with quote
Using the Slim Jim drawing borrowed from an english site -there is an easier way to make a slim jim. This version is stronger, and cheaper
to construct. (Use the drawing that says "Aerial Construction" on the top.)

The Desert Slim Jim

You start with a 3/4" (19mm?) by ten foot length piece of 200 psi PVC pipe, or the 125 PSI version. It is very thin, and very light weight.
Do not use schedule 40 or other thick, heavy plastic pipe.

Cover the Pipe "Lengthwise" with fiberglass reinforced packaging tape.
This tape is almost clear & you can see the reinforcing strands of fiberglass running lengthwise. 3M makes the good stuff. Overlap the tape so the effective cover is two layers from top to bottom completely around the pipe. Next, run another complete layer half way up from the bottom. 3/4" or 1" wide tape is good to use. When done, the pipe will have three layers covering the bottom half and two layers covering the top half. -all the way around.

You end up with a length of pipe that is very stiff, flexible to high winds, lightweight and contains no metal.

Do the math to convert the given lengths in the drawings in mm
to the length needed for the frequency you need. Convert all lengths by the same frequency. For example: 98mhz times 2.205M = 216.09 divided by the new frequency (for example) 95.5mhz = a new overall length of 2.263M Do the same math for feedpoint length and breakpoint
length. The "open gap" length at 37mm is fine for all 3 meter frequencies.

Measure from the top for locating the wire. Apply the over all length
and make your mark. Next, apply the other two measurements from the bottom mark, measuring "up" from the bottom. I have used a 16 gauge
multistrand copper wire, it weighs very little and will easily handle 125 watts. It might handle 300 watts as well but I have no experience at those higher power levels.
Start by running the wire up one side of the pipe starting at the top of the Gap, make a small notch across the top of the pipe to set the wire into
and run it down the other side to the bottom mark. A small 1/8th inch hole will have to be drilled clear through the pipe at the bottom mark, If you do not have a drill a soldering iron could melt a small hole through each side.

Beware of fumes!

Pass the wire through both holes and run it back up from the bottom to the "gap" With more of that reinforced fiberglass tape secure the wire every foot or so, taking care not to put tape over the feedpoint area plus or minus two inches.

Take the coax and tin each end of the wire after making about a one inch lead out of each conductor. "tack" solder the coax at the measured feedpoint. For simplicity, the outer coax lead is attached on the "gap side" at the feedpoint, while the inner coax lead is attached to the opposite side where the wire runs up and over the top. (the long side) Set the slim jim up vertically on a temporary pole or taped to a wooden ladder in an open area. Check the SWR using a very low power setting, even less than one hundred milliwatts should work if your SWR meter is sensitive enough. Move both wires up 1/4 inch or down 1/4 inch till you find a 1 to 1 SWR. Sometimes no movement is necessary. Permanently solder the leads after bending the leads around the 16 gauge wire a bit, dont use too much heat.

BTW: It is not necessary to have the bare 16 gauge wire stretched tight, a wee bit loose is OK !

After things cool, use some silicone RTV Blue automotive gasket maker
sealant, cover the end of the coax all over so both leads are immersed in
the silicone and the outer coax covering is overlapped with silicone sealant. From the ends back to the outer covering on the coax, no more. Sabe?
Less than a teaspoon of RTV Blue total.


Take a one inch dia. by ten foot length of common mast pipe from Radio Shack or wherever. Saw off the small "male", formed end of that pipe that normally fits into the larger (female, straight) end. Slip the Slim Jim
inside the mast pipe, till the bottom of the over-all length is 8 inches away from the mast pipe, (the bottom of the 16 gauge wire?) you will need a bit of that fiberglass tape to make it a very snug fit. Plan to Drill one 1/4" hole near the bottom end of the PVC pipe. Try to hit at say 9'- 10" down from the top of the PVC.

****Do not drill the hole near the top of the of the mast pipe, it would weaken the plastic pipe near the highest stress point! ****

This drill hole measurement will fall a ways down from the top of the mast.
This measurement will vary according to the Electrical frequency/length of the Desert Slim Jim.

Once again, Drill through the mast, with the plastic pipe inserted so that it 8 inches is between the mast and the bottom of the overall mark.

Tape the coax down the side of the Desert Slim Jim, leaving a bit of slack
(partial loop) near the feedpoint, that way the soldered leads will not rip off
in a strong wind. This antenna is designed to bend in high winds a bit, which is good! Use duct tape or fiberglass tape, three or four layers is a good idea at each tape point. Paint the whole plastic part of the antenna with some cheap white titanium based paint, the $1.88 stuff works very well. Use three coats, let it dry well between coats. Be sure and ground the base of the mast pipe for your protection from Electrical Power lines and Electrical storms. Make sure the antenna site is 1.1 or more times farther from any overhead electrical hazzard than it is tall.

If you are going up twenty, thirty, forty, or fifty feet, Belden 9258 RG-8x gives very good performance for the money & Less than one Db loss. I attach a whole length to the antenna and that way I only need one connector at the Exciter.
At less that 40 feet high, this antenna when paired with a 1 watt exciter will reach cars for a solid 2+ miles on flat terrain.
Mon Jul 05, 2004 8:09 am
Strominorm/Fleetinglimpse
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Post Well certainly Cheaper..But not stronger Reply with quote
Are you stationed out in Irak or Afghani?..Watchout for them desert Snakes
Tue Jul 06, 2004 7:33 am
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