>The cover foto Tom, N2SR, was commenting on to Bill, N4VJ/???, was one
>of a series of cover fotos over the years of Frank Clements antennas.
Terry is correct. But I detect a bit of confusion about some details in
subsequent posts so I'm tempted to set the cyber record straight....
There were two QST cover photos of W6KPC arrays in modern times. There may
have been a third, actually, way back in the early 50's but I'm too lazy to
look for it.
November, 1969 QST had a cover photo and very detailed construction article
of Frank's rotating array for ten meters which he called a "stacked,
collinear yagi quartet." This was a gorgeous array of four 6-element yagis
with 25-foot booms. Each side-by-side pair was mounted on a non-conductive,
25-foot cross-boom made of spruce wood. There was about 25 feet of vertical
separation between the two horizontal booms, using a chrome-moly mast and
(of course!) a prop pitch rotator, all mounted on a Tri-Ex LM-470HD tower.
Re-reading this article after all these years was a real eye-opener because
the information provided by Frank about stacking details is so excellent.
Remember, there was no computer modelling then! There is an appendix about
how to calculate windloads and related items, too. This is truly a classic
article which should be examined by anyone planning a stack of any kind
(along with W2PV's stuff, too).
The second W6KPC cover photo was June 1980 QST, in color. This photo and a
much shorter article inside (QST had already started editing "good stuff"
for the masses?) concerned Frank's twenty-meter version of the earlier
ten-meter array. At the time of the photo, there were "only four" of the
planned six yagis in place; so it was just a collinear yagi quartet. Later,
he added a rotating, custom-made ring mount partway down the rigid part of
the tower, and put another side-by-side pair of yagis on a third crossboom
there. Each yagi was a KLM 6-element on a 57-foot boom, and each pair was
on a 66-foot crossarm made of fiberglass and steel, for a total of only 36
elements on twenty!
This antenna was active for many years (Frank is primarily a DXer, not a
contester) but as Ron Hill pointed out, it suffered major damage 2 or 3
years ago and as of last April, when I saw it while driving back from
Visalia DXC, it had not been repaired.
Incidentally, near the main house Frank has a 100-foot skyneedle which had a
side-by-side pair of M-Squared seven element yagis for 15 meters on a
crossboom. At the moment I can't recall whether it was just a pair, or
whether it was a quartet... maybe Ron can tell us. In any event, it was a
Frank will probably be at Fresno this weekend. Read the 1969 article on the
ten-meter quartet, and when you see Frank at the convention, thank him for
putting that extremely informative article into the antenna record.
73, Glenn K6NA
FAQ on WWW: http://www.contesting.com/towertalkfaq.html
Administrative requests: towertalk-REQUEST@contesting.com