[BC] Repacking the TV band

[James B. Potter]

Rob: 

I am familiar with the design and app of Yagis and Logs.  I have always
viewed TV antennas as Yagis with elements carefully interspersed and trimmed
to length to physically fit down the boom.  It was pretty cool how those
designers interspersed the low-band and UHF elements, and how the whole
she-bang actually worked with respectable VSWR and gain!  It always amazed
me they worked at all given the mutual coupling among elements.  There were
ham articles on how to trim the elements and adjust the spacing for use on
ham 2 meter and UHF bands, too.  I don't believe the common 'fish spine' TV
ants are logs, though. Logs have tapered elements all of which are 'driven'
(electrically live) with center feed points crossed over from element to
element.  TV antennas have just one live element and connection point for
the coax or ribbon cable.  The other elements are either directors or
reflectors -- characteristics of Yagi designs, no?  

In the Phila area since the 1950s, we had Channels 3, 6, 10, and 12.  Just
about every house in the Phila area and outward on all compass points plus
the Jersey shore had bowtie antennas on the houses back then  Later when UHF
came along, they sprouted mini-bow-ties for Channels 17 and 48.  Those
antennas must have been designed for VHF low-band also, by the evidence of
use.  The bow-tie is just a physically broad dipole element for wide
bandwidth.  On UHF, there was usually a reflector behind the little bow-tie.

Thanks/Regards/Jim 

-----Original Message-----

 From: Robert Meuser

Bowties have always been manufactured as a UHF antenna. Check the Channel
Master site. They are preferred for DTV because of the wider beam width. BTW
yagis are not usually broadband you may have them confused with log
periodics.