On (04 Jan 97  18:29:08) Rob Dennis wrote to Larry Kunz ...
RD>  The reason I have to stay away from it is the length of the thing (over
RD> 20ft)
The Diamond is 22'!
RD>  LK> decouple the RF from the outside of the coax. You would think that
RD>  LK> this is one purpose of the ground radials, but placing them about
RD>  LK> 12" ABOVE the feed point seems just plain wrong!
RD> 
RD>  12" ABOVE the feedpoint? That's stupid.
Agree...
RD>  Even Cushcraft's 2m Ringo series ALL have the ground planes integrated
RD> into the main co-ax connector/phasing line.  And their groundplanes are
RD> half an INCH away from where the co-ax screws into the antenna.
RD>  Wonder what `genius' decide to move the gnd planes that far away?
I have a Cushcraft ARX440 (I think) it is the 440 5/8 X 2 ground
plane. The construction is sort of `weak' but at least it tuned and
seems to work.
RD>  Can't you de-couple it by making a small `service/drip' loop where the
RD> co-ax
RD> goes in? Surely a small coil of one or two turns of co-ax near the
RD> connector should work as an free-air RF choke to solve the problem.
RD>  BTW I'm using RG-8X to feed my 6m ringo and have a small,4 inch
RD> across,coil of
RD> the co-ax just under the connector where it goes in.
I plan to do that and add a couple of clamp on ferrite chokes for
good measure.
RD>  No TVI/RFI to me or anyone else on FM,AM or SSB.
RD>  What are you using for co-ax?
I feed this thing with about 80' of 1/2 heliax to a 10' pig tail of
RG-9.
Larry - WA5KBQ
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