From Phil's 09/13/03
After trials with 90 degree welded hubs
VK2ABQ style , I then went on to the g6xn moxon and then again on to the
w4rnl version with the 40/140 degree angles, as a single bander on 15 meters
this seemed awesome against my reference dipole and stayed up in the air for
over 12 months. The desire for more efficient multi bander prompted me to
look at the Hexbeam and correspond with EI7BA John Tait who was very helpful
as well as Dave Douglass VK2DPD who is well into home brew hexbeams.
So , (see above
photograph) this moxon frame started out as an attempt at a HEXBEAM with
centre hub being a 1.5 inch hexagon nut around which I welded 6 x 2 foot
long pieces of 1 x 1 inch angle iron. Initially I used cable ties to hold
the 5 metre long fishing rods in position. When I reverted back to the
MOXON, I left the angles at 60 and 120 degrees just pushing in two of the
opposing rods which acted as good support for the feeders and opposite side.
This prototype has been up in the air nearly 18 months now and has withstood
all sorts of weather thrown at it !! In fact, the wires have stretched
a bit I think, and resonance isn't as good as when it first went up but it
seems to be doing the trick so I have left it for now.
All four bands are fed
independently with feed points soldered and sealed with silicone then
bound for good measure with self amalg`g tape. Using the KISS
approach, I actually salvaged my single band MOXONs!! This is where the
two extra fishing rods came in useful to support the weight of the RG58 on
the one side and of course to balance the whole thing off on the other
side. She really had to look the part for the XYL!!
It was no picnic for
tuning even with the MFJ analyser - up down, up down, up down. In the
end I put little wire tails on (see above photograph), hanging from screw
connectors to adjust for best resonance . Fortunately they haven't
touched yet !! I call these my WaSP tails. HI HI
The bracing is thin
polypropylene line taken from a raised centre pole flexes the tips of the
rods (hexbeam style) thus sort of layering the 4 bands at each of the ends.
A simple glue gun comes in handy here for tacking in position. I use
cheap stranded copper wire - the lengths and critical distances
(disregarding the WaSP tails !! ) used are from Cebic W4RNL's info.
While I most certainly don't claim full optimized performance, I know that
my MOXON is working well from the comparative reports that I have
received over the years.