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Re: "J-Beam" Antenna



At 02:03 AM 8/28/2002 +0000, John Beanland wrote:
***snip***
>	The "Skeleton Slot" antenna was conceived and developed by Bill Sykes,
>G2HCG, in the late 1940s. He obtained a patent and the design became the
>basis of his company, Jaybeam Limited. The original Skeleton Slot was a 2m
>antenna. It was basically a vertical Loop Antenna that was fed, with a
>balanced feed, on opposite sides; hence the polarisation was horizontal.
>The loop was not circular, nor was it square. It was "stretched" vertically
>into a rectangle. He then added a horizontal Director and a Reflector
>element in the plane of the top and bottom sections; hence he had a pair of
>3-element beams. But the driven elements were not "full length" dipoles.
>They were just the centre section of equivalent dipoles (where the current
>is maximum, which is what you want). Later 2 more Directors were added at
>each level making it a pair of 5-element Yagis stacked one above the other
>and having the common slot driven element. The D5-2M, as it was known, led
>to the D8-2M by adding 3 more directors to each Yagi. This was a very
>popular antenna in England and in Europe. The D8-2M was also imported and
>sold for several years in America. 
***snip***
>	73s,   John  G3BVU/W1.

Ah yes, I remember it well!  In 1965 I was living just east of Jackson,
Michigan, and having just got out of college I satisfied ham radio urges
that had been put off four years for my studies!  It was a Johnson 6N2
AM/CW 150w transmitter and a Clegg Interceptor-B 6m/2m receiver.  For my 2m
antenna I bought the 8-over-8 skelton-slot yagi and mounted it 60-foot on
top of a EZ-Way crank-up tower.

Because Jackson was roughly in the middle of the lower part of Michigan and
nearly half-way between Detroit and Chicago, and because Jackson was a high
elevation point in that span, I enjoyed nightly conversations with hams in
both cities by pointing at Chicago with Detroit off the back.  Most were
the early 2m-ssb stations of the time, but did not object to my strong
plate-modulated AM signal since I was xtal controlled and very stable.

Your describing the antenna brings back fond memories of my early years on
2m!  I later bought the 10-over-10 432 Skelton-slot antenna...in 1972 it
was used in the Californian Mojave Desert briefly for the UHF uplink
antenna of the AO-6 west coast command station! 

Ed, AL7EB

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