"This B&W Antenna sort of reminds me of the infamous MaxCom antenna feed
which gave a VSWR of less that 2:1 from 1.8 to 30 Mhz sold for a while in
the 70's and 80's. After scamming thousands of hams with these claims the
ARRL lab put the potted matching unit into a X-ray device and learned that
it was nothing more that a series of toaster elements across the feed point
inside or a dummy load on the end of your coax with some wire attached to
it."
ARRL members can access the MAXCOM product review in the link below. The
review shows X-Ray images taken by League staff back in 1984.
http://www.arrl.org/files/file/protected/Group/Members/ProductReview/pdf/pr8
411.pdf
In 1984, prices ranged from $600 to $1,000 for the 2KW unit. As long as
facts are presented, I have nothing against the MAXCOM concept (or the
broadband dipole), and apparently various military government branches using
the BB dipoles are fine with a >3 dB power hit in the interest of a "no
tune" operation. At legal U.S. limit, these things must get very hot. The
B&W BB dipoles use six, 50-ohm resistors (QST, March, 1981, pp. 50-51.)
The difference here is that the MAXCOM device was sold as an "automatic
antenna matcher," conjuring up images in the prospective purchaser's mind of
a sophisticated, low-loss switching device. As I recall, MACOM's ads
contained no direct misrepresentation. The device indeed presented a fast,
automatic match (less than 2:1) between line and antenna, but did so at the
cost of adding severe loss. The result is no different than if one uses
long lengths of lossy transmission line. In such cases, as more line is
added, an SWR meter at the transmitter end of the line looks better and
better as more cabling is added, owing to higher *return loss.*
So, did truth in advertising mean full disclosure of MAXCOM's losses?
Caveat Emptor, I say.
Paul, W9AC
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|