I believe what Sam did was copy an AEL antenna design that was
originally intended for 18 GHz for SIGINT aircraft usage, but Sams (ISA
founder, and one of F.G. Mason techs) version was really only
successful to about 8 GHz, lacked the microwave connector, and lacked
the mounting studs.
ISA tried to sell the antenna on the end of a wand which was a good
idea, but it did not dawn on them (curses, foil again) to park a filter
and pre-amp in the handle, so that when the electrons started flowing
down the wire at the higher frequencies only a miniscule amount was
actually getting into the detection system as the cable and connector
was only rated to 1 GHz (not 18 GHz).
If your going to do bug hunting beware the cables, and beware the
connectors for they can foil your plas with even a good antenna design.
The AEL log periodic was the best little unit made, and thousands and
thousand got pumped out worldwide and it was likely the most popular
antenna they made. The next most popular was their Litz wire mini-loop
in the little fiberglass box with a similar mount.
-jma
Norbert Zaenglein wrote:
Does anyone know (or can estimate) the upper and lower frequency
range of an ISA Log Periodic antenna? The antenna was part of an ISA
ECR-2 system and has 28 elements. Antenna portion is
approximately seven inches long, about twelve inches including the
handle. Antenna is terminated in a BNC connector.
Any insights appreciated.
Norbert Zaenglein
ACSS
P.O. Box 1
Clay Center, NE 68933
--
James M. Atkinson
President and Sr. Engineer
"Leonardo da Vinci of Bug Sweeps and Spy Hunting"
Granite Island Group
jm..._at_tscm.com
http://www.tscm.com/
(978) 546-3803
Received on Sat Mar 02 2024 - 00:57:22 CST