[Towertalk] Force 12 Sigma verticals

John Petrich petrich@u.washington.edu
Mon, 18 Mar 2002 11:42:53 -0800


Bob,

    I have not actually constructed my array just yet.  Have been using a
single Sigma 80 on 80 CW for this past season and have compared it's
performance to known antennas at this QTH.

    1) The "standard" Sigma 80 is constructed for the SSB portion of the
band.  Mine wouldn't resonate below about 3.650 MHz.  Had to order some 1"
tubing extensions to get resonance to 3.510 MHz.  Not sure what frequencies
you are interested in, but bear this in mind if and when  you order.

    2) The bottom line is that the Sigma 80 seems to perform equally to my
full sized 1/4 wave GP, 20' elevated feed and 6 elevated radials.  The band
width is, of course, much narrower.  My 150' dipole is better for higher
angle signals and less effective for LP than the vertical or the Sigma 80.

    3) I rationalize the high cost of a Sigma 80 based on the vastly lower
"hassle" factor compared to the alternatives (at this QTH) and the reduced
"clap trap" factor in the garden.  I am putting mine up in September and
taking it down in March.

    4) My plans are to construct a fixed 2 element array for next year.  The
design options are many.  I'm a firm believer in Roy's, W7EL, approach to
driven arrays reflected in the ARRL Antenna Handbook.

    Sorry that I cannot give you any first hand experience with the Sigma 80
in an array.  Next year.  Maybe others are working on some and will respond.

Regards,

John Petrich, W7FU


----- Original Message -----
From: "Finger, Bob" <Bob.Finger@DynCorp.com>
To: <towertalk@contesting.com>
Sent: Monday, March 18, 2002 11:14 AM
Subject: [Towertalk] Force 12 Sigma verticals


> Has anyone built a triangle or 4square array using the Force 12 Sigma 80
or
> 40 verticals?  If so, what are your reactions both good and bad.  Seems to
> me like it might well be an effective solution (but expensive) to limited
> space where a full sized radial screen is not feasible.  Thanks for the
> comments.  W9GE
>
>
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