Joe, and friends
What I think you're looking for was a military product made by Collins Radio
Co. which is now Rockwell.
The antenna was a pair of silver plated steel tapes (much like a common
measurement tape) marked in Cementers and motor driven. The control unit
would adjust the length of the silver tapes to a preset configuration. It
had about 12 channels and came in different frequency ranges. The lowest
being 2 to 30 mHz. That is about all I remember, but it is an interesting
idea and would allow the automation of site attenuation and may be better
than using biconicals.
Al Patrick, Sr. EMC Engineer - Scientific-Atlanta Inc. 5030 EMC Lab.
[email protected]
-----Original Message-----
From: Price, Ed [mailto:[email protected]]
Sent: Wednesday, January 19, 2000 1:27 PM
To: '[email protected]'; [email protected]
Subject: RE: Looking for tunable dipole antenna.
> -----Original Message-----
> From: [email protected] [SMTP:[email protected]]
> Sent: Wednesday, January 19, 2000 5:53 AM
> To: [email protected]
> Subject: Looking for tunable dipole antenna.
>
>
> Does anybody have any idea on where I can purchase a set of dipole
> antennas
> that have tunable baluns? I need them for performing pre-compliance
> antenna
> gain tests on some of the antennas that are used on the various Racal
> handheld radios. The frequency range I am interested in is the 30 MHz to
> 1
> GHz frequency range. I am interested in either used or new antennas. I
> had
> a set of them about 20 years ago but don't remember whether they were home
> made or something we purchased from some manufacturer. If you have any
> ideas for a source please let me know.
>
> Thanks,
> Joe O'Banion
>
>
Joe:
First, I wonder why you prefer a tunable balun? But assuming you really do
want that, it makes the selection rather narrow.
The only tunable balun I have ever seen on a test antenna was the old
Stoddart 91598-2 dipole, which operated between 375 MHz and 1000 MHz. Not
only did you have to adjust the length of the dipole arms for each
frequency, you also had to adjust the position of a sliding short on the
twin-tube "boom". (I'm not too certain about this, but the twin tubes and
the sliding short may have been what's called a "J" match.)
However, the other associated Stoddart dipoles, as well as Empire's,
Eaton's, AH Systems' and Schwarzbeck's dipoles all used fixed baluns. The
91598-2 is so old that finding one would very difficult; accessories like
antennas often go astray from the equipment (the NM-52A EMI Meter) when the
equipment is scrapped.
Regards,
Ed
:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)
Ed Price
[email protected]
Electromagnetic Compatibility Lab
Cubic Defense Systems
San Diego, CA. USA
858-505-2780 (Voice)
858-505-1583 (Fax)
Military & Avionics EMC Services Is Our Specialty
Shake-Bake-Shock - Metrology - Reliability Analysis
:-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-):-)
---------
This message is coming from the emc-pstc discussion list.
To cancel your subscription, send mail to [email protected]
with the single line: "unsubscribe emc-pstc" (without the
quotes). For help, send mail to [email protected],
[email protected], [email protected], or
[email protected] (the list administrators).
***
---------
This message is coming from the emc-pstc discussion list.
To cancel your subscription, send mail to [email protected]
with the single line: "unsubscribe emc-pstc" (without the
quotes). For help, send mail to [email protected],
[email protected], [email protected], or
[email protected] (the list administrators).
