SIGMA-80 Vertical
"This is not your Daddy's vertical!"
This is a brand new, high performance vertical for the 80/75 meter band. Consuming over 4 years of elapsed time for several designs and long term testing, the SIGMA-80 will open your eyes on the popular 80/75 meter bands. If we knew how to make it better, we would do it! The only thing to enhance the SIGMA-80 is to place it adjacent to salt water.
Plots of single element and 2 element SIGMA-80 vertical dipoles are shown below.
The SIGMA-80 vertical is the latest in the SIGMA line. (The development of the Sigma series can be read about on the SIGMA 40 page.) Since many people have desired a high performance vertical for the 80/75 meter bands, this was a natural, it simply took some time to get it right. With the SIGMA series, there is no need for taking up your real estate with radials ( for two full-length radials ). The SIGMA 80 is "self contained" with its T-bar construction and is guyed once for high wind survival.
The name for this new vertical is "Sigma." This is the Greek mathematical symbol meaning "the sum of" and the Sigma series is truly the sum of years of experience, designs and testing. Not all ideas were successful, but that is the manner of research.
SIGMA-80 80/75 METER VERTICAL DIPOLE |
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SIGMA 80 36' tall, plus base 90 mph, guyed once 47 pounds 70 kHz 2:1 VSWR 5KW rating |
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The Sigma verticals are all vertical dipoles. This means they do not need radials, so the real estate needed is minimal. SIGMA 80 verticals have been in use since February, 2001. The photo is from the Field Day site of W6R in 2001. The vertical produced many east coast QSO's and many questions about what antenna we were using. Another west coast station used one for about 6 weeks this past summer and worked 24 countries, including Europeans and TY (Africa) - not bad for summertime!
The SIGMA-80 is guyed once, rated for 90 mph and 5KW. The SIGMA-80 is bolted together and the loading technique is a combination of T-bars at the top and bottom of the antenna, plus high-Q coils at the center. The coils are non-adjustable and tuning is very simple -> adjust the length of the T-bars. The SIGMA 80 comes with compression clamps to make initial or temporary adjustments on the T-bars, plus rivets to complete a permanent installation.
A heavier model is available (and has already been shipped )for extreme weather conditions - please contact the factory for details.
DXpeditons have also used the SIGMA-80 --> XT2DX in the 2001 CQWW CW competition.
Get the high performance Sigma-80© from Force 12, Inc., your performance antenna company!