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THE N9AGT
VERSION OF THE SLIM JIM
ANTENNA
This
is the Slim Jim Antenna I made after reading KE5FXU, Richard's article on
Hamuniverse.com.
I used readily attainable parts to assemble
it with. It cleaned it up and made it real easy to look at...as well
as functional! In the pictures below you will see I used PVC tees
(Pic # 2) with a 1 1/8" bushing cut from 1/2" PVC
pipe.
The tees need to be reamed out with a 5/8" drill bit for a
snug but sliding fit for placement.
For the tuning stub (Pic
# 3), I used 1/2" copper couplers that slide on the 1/2" copper
tubing. DO NOT use the couplers with dimples or grooves in them,
these will not slide on the pipe!
I soldered an SO-239 connector
to the 1/4 WL pipe and then soldered a piece of solid wire between the 3/4
WL pipe and the center conductor on the SO- 239 connector. You could
solder the coax or ladder line directly to the sliding couplers. I
personally will use the SO 239 connector on this antenna.
The
pictures below will help show how it all went together. Maybe
this will give you some more ideas on how to construct your Slim Jim
antenna!.
Pic #1 Full Length View
Pic #2 PVC "T"s
Pic #3 Sliding Couplers and tuning stub area at
base
The pictures below show the
final assembly with the SO-239 installed.
Back view of SO-239 installed
Front view of SO-239 installed after final
tuning.
(Antenna is upside down in view
above)
I soldered the center conductor to the 'long' side of the
antenna and the SO-239 base plate to the 'short' side.
The gap spacing ended up being 1 1/4". The distance from the
bottom of the antenna to the center conductor on the SO-239 ended up being
3 1/4".
I could have left the "tap" or feed points at
Richard's (KE5FXU's
project), measurement of 1 1/2" and 4" and would have been fine
with a SWR of 1.5 to 1. I got it down to 1.2 to 1 or less across the
band!
After tuning for lowest swr, I then soldered the
bushing/couplings in place along with the end caps at the gap. I
love these 'one wave length or longer' antennae! Actually, if
you measure from gap end to gap end around the antenna, it is about 1 1/2
wave lengths long. The tuning stub takes up part of that so you could call
it an end fed folded "long wire" or any other name you want to call
it.
I think that with a little more tweaking I could have gotten
the SWR down less than that! I just don't like being perfect!
LOL.
Some time back I also built the 2m Hentenna that was
on the Hamuniverse.com antenna projects
page. I use that antenna at my home now and can't say enough
good things about it.
This Slim Jim performs on par with the
Hentenna and I will
use the Slim Jim at my QTH in Arizona when I get there in middle January
for the rest of the winter!
I have no doubts that at my location
(Florence, AZ.) I will be able to make contacts in both the Tucson and the
Phoenix areas which are nearly equal distance north and south.
That will be a great test for this design! Thanks for a great
website for experimenting Hams!
Having HAM fun, N9AGT
Roy.
If you feel that
this article has been of value to you, please make ANY donation to
help maintain Hamuniverse.com! Thank you in advance for your
kindness!
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