[SMCARA] Slim Jim

[Clarke, Tom AIR4.0P NATOPS]

I have been collecting info on the slim jim and thought I would share it
with you.

There is a ton of stuff on the web, and this is just a small collection
of info to get you started.

Remember a lot of antenna work is considered "experimentation", i.e.,
"cut and try"!

The excel spreadsheet is a compilation of dimensions, both metric and
English.

The .gif's will give you an idea of the different ways to put one
together - from a "plumbers delight" to something slapped together with
twinlead, wire, pvc, or whatever you have in your "junque box".

The vertical beamwidth of this antenna tends to be a bit narrow, so you
might shoot over a close in station, especially if it is on top of your
100 foot tower!  Might be fun to experiment with this by installing it
(temporarily!) off vertical and seeing the effect on signal strength.  

An interesting example of this is cell phone coverage.  Verizon
installed a cell site on the water tower in Wildewood and we all thought
our dead spot problem was gone.  Wrongo!  Kemo Sabe!

With the antennas on the top of the water tank and aimed at the horizon,
we had some major dropouts.  I live about a 1/4 mile from it and had
problems.  There was some serious shading going on and after a lot of
complaints, Verizon moved the antennas and we now have great coverage.
I wish my 2M antenna was up there! (about 200 feet up)

In case you don't have Excel, here is a copy (go full screen or it will
scramble)


		Dim A		Dim B		Dim C		Dim D
Dim E* 	Dim F**	
		Overall	Half Wave	Qtr Wave	Feed Pt	Gap
Spacing	
Frequency							
50.125	4m 15cm	2m 8cm	1m 4cm 	15cm		10-12cm	2-3cm	CM
		167.8"	110"		55"		6-8"
3"	 	3" to 6 "	
		14' 11"	9' 3"		4' 6" 	6-8"		3"
3" to 6 "	
							
146.000	144.9cm	96.6cm	45.7cm	7.5cm		2.6cm		3-4cm	
		57"		38		19		3-4"
1 1/2"	1" to 2"	
		4'  8"	3'  3"	1'  7"	2" to 4"	1"
1" to 2"	

							
222.000	95cm		63.5cm	32.75cm	2-4cm		1cm
2cm	
		38"		25 1/4"	12 5/8"	1" to 2" 	1"
1"	
							
445.000	47cm		32cm		15.8cm	2cm		<1cm
<1cm
		19"		12 5/8 "	6 1/4"	1" to 2"
1"		< 1"	
							
				Adj for these for best VSWR -->	*Approx
** Non 	
	
Critical

73 de Tom/W4OKW