Hi David, and Gang
I am familiar with the ZX mini-yagi, the one with traps in the
elements,
3 elements, 6 ft. boom. Although mine is not in the air, it will be
shortly.
I have no info suggesting that it was designed by ON4UN, so i cannot
confirm that.
The hardware is stainless steel, its an easy to put together antenna,
there
are no adjustments. However there are some mechanical/electrical
integrity
problems that need to be worked out with it. This requires that you
replace a
few screws with longer ones before you assemble it. If you don't you will
be
disassembling it to do so, after the fact. Trust me, i discovered it the
hard way.
Apparently the antenna is so new that they had not debugged it by the
time i
bought one back in the early summer.
Recently, i saw where another subscriber to towertalk, had one and
appealed
for help on the reflector. I shared my experience with him and he
successfully
repaired his and has it back up in the air. He seemed positive in his
initial report
of his experience with it and i'll be interested in following it .
The center of each element is a phenolic rod, used to insulate each
respective
side of an element from the other. The rod also serves as a form on which
to
wind the loading coils. Since the loading is in the center of each
element, it isn't
possible for the antenna to be as efficient as an unloaded antenna,
because that
is where the high current part of the element is. The 10 meter part of
the antenna
element is only 8 ft. across, and the boom is only 6 ft. long. Claims for
the gain
of the antenna is only 4.5 dbd for 10, 3.8 for 15 and 3.2 on 20 meters. I
doubt even
those figures. Closer to 0 dbd might be more like it. Power handling
capability is
touted as being over a kilowatt( i don't remember for sure whether it was
as high
as 1500 wts. PEP).
But even if the gain of the antenna were zero on all three bands, i
think that the
compactness of the antenna, coupled with some front to back and front to
side
ratio and its cost( a bit over $200 now), may well prove to be
"redeeming" features.
After all, you still get the "up to 6 db" of ground reflection gain and
if you get the antenna
in the clear, it might not prove to be a half bad performer. While 6 ft.
is hardly enough
boom to permit optimum spacing for the elements, it may be that shortened
elements
are unable to be coupled properly to each other, parasitically, without
such short spacing.
I bought mine for a limited service, limited duty application because i
was planning only
to have a 30 ft. tower, bracketed to the house.Before i got mine up, it
became possible
to build my larger tower in the backyard. Therefore i abandoned the
application, and i will
ultimately sell my ZX mini-yagi. But because i would like to satisfy my
curiosity about its
performance, and would like to be able to describe my results with it
accurately, i do plan
to put it on my 52 ft. tower, in the next few days, and possibly use it
till spring. At that time,
i will replace it with my T-6 log periodic and using the results from the
ZX mini-yagi, will
serve as a baseline for comparing the log.
I'll be glad to share my results with you, if you wish. Just check back
with me occasionally.
Good luck in all endeavors, antennas included. 73 Roy WA4DOU
-------------------------------------------------------------------------
--------------------------------------------------
On Wed, 1 Dec 1999 00:23:18 -0500 "DavidC" <eDoc@netzero.net> writes:
>
> The European ZX-YAGI company http://www.zx-yagi.nl/ seems
> to have US distributors, including one in CT, MTEnterprises
> www.qth.com/mte/ E-mail N1MT@Javanet.com , and one
> here in FL www.freeyellow.com/members6/profet/ or
> RFREPAIRSTATION@HOTMAIL.COM showing an
> E-mail address: pym6166@bellsouth.net
>
> The beams are said to use designs by ON4UN John Devoldere.
> Anyone have additional online resources describing his work?
>
> Anyone familiar with the performance and reliability of these beams,
> please? Other comments?
>
> My natural preference is for US made products for service and
> support and other reasons but I am curious just the same ...
>
> - Thanks! & 73, DavidC K1YP
>
> Sure hope they aren't marketing the 11 meter beams in the US ...
> isn't the use of beams on 11 meters illegal here? :-)
> http://www.zx-yagi.nl/specifications/index.html
>
>
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>
>
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