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RE: L Band Uplink Experience - AO40



Hello John

Adding to Mark's comments, which certainly reflect my findings too, I also
have the same 23 & 13cm antennas (20t & 30t).

On the fragility, once they're up it's not a problem - unless you have a bit
of coax get stuck in the way as the rotator moves around. They're delivered
in cardboard tubes to protect them, but in my excitement to pull them out I
managed to slightly mangle the soft aluminum helix. It's easy to put back
into shape, but of course it never _looks_ as nice as perhaps it might once
have been.

I've been able to measure the SWR on both the 23cm and the 13cm and they com
in at 1.2:1 and 1.3:1 respectively at 2400MHz, with no adjustment necessary.

By the way, I discovered that a Diamond SX-1000 SWR meter, although only
rated upto 23cm, also does sterling service for sanity checking SWR
measurements at 13cm to. The power indication is only barely 20% out too at
this frequency. You'll need a 13cm power source at about 1W or higher.

I did a number of rough comparative measurements between a number of
antennas at 13cm, including the Wimo, a K5OE 20 turn, a Sandpiper 20 turn
and a 15 element yagi, and the Wimo 30 turn was undoubtedly the best, by 3dB
or so.

I'm intending to upgrade the helices to something else in due course as
Mark's already done, but if space/visiblity is a concern, the Wimo's still
perform well.

73 Howard G6LVB

>Hi Mark, I was wondering what your thoughts were on the
>Wimo helix antenna.  I'm thinking about purchasing one
>but you're the first I heard that actually put one to the
>test.  How's the quality and construction, etc. ?
>
>TNX & '73,
>
>John
>N2HMM

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