This is interesting, Dave.
They only give dimensions for the 2M.
I assume that the #12 wire wound around the long pole is the gamma
capacitor. I also wonder what the sun & time does to the insulation on this
wire.
In this version, the SO-239 is exposed to the WX as is the PL-259 screwed on
to it. In the more usual
"run-the-coax-up-to-the-feed-point-and-solder-or-clamp-it-on" method exposes
the coax end to the Wx - allowing seepage into the coax.
I am trying to figure out a good way to get the feed line completely
INTERNAL when using the "tap-the-coax-up-a-ways-on-the-matching-section"
feed method. This is so the feed line and the connector (if needed) is
not exposed to the Wx.
Sumptin' like this:
Drill a hole in the long pole, facing the short pole, where the feed line
will attach. However, if you try to solder the shield here and just extend
the center insulation and center conductor to the short pole, water can
enter the coax. Trying to put a SO239 or something smaller (and probably an
elbow version), inside the long pole at this point (to take advantage of its
"sealed" construction) is difficult. You could put a "thru joint" right
below that point to improve access for soldering such a connector -- that
may do it. Or you could use a pipe "T" with the lone opening facing the
short pole and do something in there to use an already sealed "something" to
go from the coax (inside the pipe) to the other side of the matching
section.
Any Ideas?
"Dave Platt" wrote in message
...
[...snipped...]
These J-poles use a somewhat uncommon feed technique - the SO-259 is
attached near the center of the crosspiece and grounded there, and the
short side of the matching section is fed through a bent-wire
transmission line and gamma match.
http://www.pcarc.net/jpole.pdf shows the construction, including the
crossbrace.
--
Dave Platt AE6EO
Hosting the Jade Warrior home page: http://www.radagast.org/jade-warrior
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