----- Original Message -----
From: "Peter Dougherty" <w2irt@nac.net>
To: "Al Toothaker" <N6TA@arrl.net>; <towertalk@contesting.com>
Sent: Monday, March 14, 2005 11:43 PM
Subject: Re: [TowerTalk] Help in planning a new QTH
> Oh, the 55' tower, yagi and VEEs were indeed both highly
> suggested and
> recommended; it was just the SteppIR that was not. Indeed,
> looking at the
> specs, it would seem the SteppIR (even the 4-el version) has
> somewhat
> significantly less gain that others, especially the Force 12
> C31XR. Thing
> is, that Force 12 is a behemoth and would NOT pass the XYL test
> in a
> million years. I think even the 4-el SteppIR may be asking for
> a lot.
You have to be careful when you read those Force 12 gain figures.
Take Force 12's "Net Gain," in dBd, and add 2.1 dB to calculate
net gain over isotropic. Then, you can compare the gain directly
with the Steppir specs. Both of these mfrs have a reputation for
publishing fairly accurate gain figures, as does M2. You just
have to be careful how you read Force 12's figures. (I wonder how
many hams get sucked in by Force 12's higher figures that include
ground reflection gain?) Once you do the conversions, the claimed
gain is as follows:
Band 4el Steppir C31XR
20 9.5dBi 8.1
17 10.0 -
15 10.2 8.4
12 10.4 -
10 10.6 9.5
Force 12's gain, swr, and particularly F/B, should vary
considerably over the width of each band. The Steppir should
remain reasonably constant over the band. The Steppir has only 11
dB F/B on 10, which shouldn't be a big issue, particularly for a
DX'er. For a DX'er, I would think that Steppir's coverage of the
WARC bands would clinch the deal.
Dave Hachadorian, K6LL
Yuma, AZ
_______________________________________________
See: http://www.mscomputer.com for "Self Supporting Towers", "Wireless Weather
Stations", and lot's more. Call Toll Free, 1-800-333-9041 with any questions
and ask for Sherman, W2FLA.
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