Topband: Battle Creek Special vertical as a simple tx antenna
w8uvz at voyager.net
Sat Jun 16 22:55:45 EDT 2007
Hello Bill etal
As one of the three "principals" of the Battle Creek Special vertical loan
program, I feel compelled to comment (hi).
I would agree with (WA4FKI) Bill's conclusion of the BCS as a simple tx
antenna for low bands - by design. It is simply a trapped vertical for 40 &
80 m, and an inverted L for 160 m all rolled into one unit. Comes in a
box/bag with guys, radials and a manual for construction - a low band
vertical for DXpeditions - add RF via a piece of coax and....
I say by "design" since it is simple as stated - a single vertical using
known antenna techniques to tx on those bands. But as a practical matter,
construction is not as simple. One needs properly resonated traps, with
some top loading for 80 m to make it all work. And the traps themselves are
more complicated than they appear with an "L/C trap" that utilizes coils and
coax stubs to provide the capacitance for the trap (stuffed inside the
aluminum antenna tubing). All this designed not to fail in subzero
Antarctic regions as well as 130 deg heat on some Pacific islands. And in
100 mph winds if encountered. Average ham doesn't need all this to venture
onto the lower bands.
Anyone who has tried to construct and tune a multiband commercially made
vertical will understand that there is some difficulty involved in getting
the antenna to resonate on all the desired bands at the same time.
Better u take your tx needs band by band and simply use a single vertical or
inverted L to get the same tx result.
The "BCS" was originally designed to help DXpeditions gain low band
capability. It was designed when many of the DXpeditions took triband yagis
for upper bands and need a compliment for lower band operation.
Today's modern DXpedition carries monoband yagis for upper bands including
40 m. Some even utilize vertical arrays for each band. Low bands may be
covered with commercially made verticals that are mostly complete in their
makeup (Titanex comes to mind, Force 12, DX Engineering etc).
Our BCS loaners are still available and work very well but the demand has
certainly declined. They powered low band signals from such rare places as
3Y5X, VK0IR, VP8SSI, YK0A, 3Y0PI, 5X4F, 3B7RF, 9M0C, FO0AAA, K5K(Kingman),
TX0C, FT5XO and over 30 other places.
But we have never recommended that hams copy the design for use as a low
band tx antenna. Not that we would mind and would, in fact, be flattered.
Use a wire hung as an inverted L or build a single band vertical - all with
plenty of radials. Or try "shunt feeding" an existing tower for low bands.
All good choices that ON4UN's book describes.
73 George W8UVZ
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