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Old 4-Aug-2019, 6:49 PM   #3
tripelo
Senior Member
 
Join Date: Jan 2010
Location: Dallas, TX
Posts: 127
JFD & Area Special Antenna

Quote:
Originally Posted by bobsgarage View Post
[B][SIZE="3"]Just for fun.

While driving around K-Town,...

Here's that weird-looking basket type device. Is it a reflector?
Quote:
Originally Posted by OTAFAN View Post
...
Thanks bobs!...
Yes, second that. Thanks bobs. Interesting antennas.

The top antenna in the 1st image above is a JFD UHF/VHF combo.




In Bobs 1st image, the front of the antenna is on the left, the part on the left is the UHF section.
The disks are directors, the part to the right of the directors is the UHF driven part
(stacked log periodic UHF elements).
The remainder V-log portion using tubular elements is a V-Log antenna for Hi and Low VHF.
The bumps in some of the tubular elements are capacitors.
The capacitors shift the relationship between the fundamental (Lo VHF) & 3rd harmonic (Hi VHF)
The capacitors allow more elements to perform the dual function (Hi/Lo resonators).




The lower antenna in the first image appears to be a VHF-only 'Area Special'.
An Area or Regional Special was custom built by a manufacturer to accommodate specific locations.
Situations like where the main signals were coming from different directions.

That particular antenna appears to be designed to receive VHF-Lo and,
VHF-Hi from the left, while simultaneously receiving VHF-Hi from the right
(possibly VHF-Lo as well but not enough detail in image to determine).

.
Attached Images
File Type: jpg JFD 1969.jpg (57.5 KB, 169 views)
File Type: gif JFD 1969.gif (21.8 KB, 168 views)

Last edited by tripelo; 4-Aug-2019 at 6:52 PM. Reason: punctuation
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