I bought one of these at a hamfest from a SK's estate and thought it was a
ARX-2 and then noticed the 52" coax harness attached to it and realized that
it was probably a ARX-2B which seems to be the same except for the 3 radials
which I guess didn't get sent to the hamfest.
Reviews of these 2 antennas seem to almost use the 2 model numbers
interchangeably so the question is... Is it worth making up a radial
system and taking another 5 feet of mast to re-manufacture this thing into a
ARX-2B?
What would be the advantage? Maybe somebody's used both.
My understanding is that the original Ringo design doesn't do a good
job of decoupling the feedline (and mast, if conductive) from the
antenna. There can be a significant amount of RF current flow on the
outside of the feedline, below the impedance-matching loop/ring. This
radiates RF which combines with that of the radiating section,
altering the antenna's pattern to some extent (I think I've heard
people say that it can cause the antenna to "squint", with its main
radiation lobe pointing above or below the horizon). Because feedline
RF depends on the length of the feedline and its grounding
configuration, feedline-RF issue makes the original Ringo somewhat
sensitive to the specific conditions under which it's installed -
works great for some people, poorly for others.
Ordinary copper-pipe J-poles can suffer from the same problem, but as
they're a lower-gain antenna with an inherently-broader vertical
pattern I suspect that the problem is less noticeable.
The coax harness and radials (which you can probably replace with
quarter-wave sections of aluminum rod-stock, suitably threaded) act as
a decoupling section, isolating the feedline from the antenna and
making it less sensitive to the conditions of installation.
You might be able to achieve a similar effect by simply rolling up a
couple of feed of the top of the feedline into a coil 4-5" in
diameter, just below the feedpoint, and insulating the antenna from
the mast itself.
--
Dave Platt AE6EO
Friends of Jade Warrior home page:
http://www.radagast.org/jade-warrior
I do _not_ wish to receive unsolicited commercial email, and I will
boycott any company which has the gall to send me such ads!