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SHUNT
FEEDING A HUSTLER 40 METER MOBILE HF ANTENNA
BY KC8SGO
MARK
GET A BETTER MATCH AND A BIGGER
SIGNAL!
"Well, it's not my invention by any means - comes from ARRL
Antenna Handbook.
It's known as shunt feed, and is quite
simple."
I use a
Hustler MO-3 mast, and RM series resonators, on a ball mount off the
left rear fender of the station wagon. I could not get a match
below 1.7 to one until I built
this. Now I get 1:1
at my
frequencies of
interest and considerable useable
bandwidth!
The coil is 20 turns, #12
solid, 1 & 1/4 inch I.D. ( closet hanger dowel works great )
spread to 5" long, ( thats 4 turns per inch ).
One end to feed
point, other to ground.
Clip lead from ground taps up the coil
to adjust the inductance used. Eight turns works perfect for 40m,
and 4 turns for 20m. Mind you, this is on a wagon - results will
vary on a sedan. It works best on a ball mount on a fender, but can
be adapted to other setups.
I have
no camera for pictures for this page but if you get a
ARRL Antenna
Handbook, it's in the chapter on mobile
antennas.
I love
it!!! - From 7.240 to 7.270 my SWR is below
1.5 to 1, and it's flat at 7.258 ( MIDCARS ). Perfect for the
1721 RTG
(see link below) and all the other groups I hang with. On 20m,
flat at 14.275 and I cover the
entire general phone segment with SWR below 1.5 to
1.
I have yet to try 15m ( no resonator ) or 10m.
I have an RM-10, just haven't gotten 'round to
it.
Made a noticeable
difference compared to the straight setup - both on TX and
RX.
Hope this
helps.
See ya on the 1721 RTG
CHECK OUT THE 1721 HF
ROUNDTABLE GROUP
73
Mark
KC8SGO
HAVE A QUESTION?
Email Mark
Here
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