What kind of antenna is this?
 

I have a photo of an antenna at the Long Marine Labs in Santa Cruz,
California. The view in the photo is to the n-n-west. I'm curious about
what looks like some sort of array of rectangular elements. Is this an
antenna, what type or frequency range? The length of the sides is about
1 meter. I can't post a binary on the newsgroup so the image is
temporarily at this url. http://www.cyberplasm.com/temp/ant_500.jpg

On Sun, 01 Feb 2004 15:24:27 -0700, ps wrote:

I have a photo of an antenna at the Long Marine Labs in Santa Cruz,
California. The view in the photo is to the n-n-west. I'm curious about
what looks like some sort of array of rectangular elements. Is this an
antenna, what type or frequency range? The length of the sides is about
1 meter. I can't post a binary on the newsgroup so the image is
temporarily at this url. http://www.cyberplasm.com/temp/ant_500.jpg

Looks like an array of broadband receiving loops. I would bet it's for
direction finding. The signals from the individual loop antennas are
electronically combined to produce a steerable antenna pattern.

You can buy similar antenna arrays from several commerical suppliers.

The loops look home made, from common plumbing parts, a mix of PVC and
copper pipe.


Jack K8ZOA

Diversity DF???

ps wrote:

I have a photo of an antenna at the Long Marine Labs in Santa Cruz,
California. The view in the photo is to the n-n-west. I'm curious about
what looks like some sort of array of rectangular elements. Is this an
antenna, what type or frequency range? The length of the sides is about
1 meter. I can't post a binary on the newsgroup so the image is
temporarily at this url. http://www.cyberplasm.com/temp/ant_500.jpg

"Dave Shrader" wrote in message
news:cGhTb.201548$I06.2220041@attbi_s01...
Diversity DF???

Could be a big loop Yagi...the wide-angle
lens has distorted the horizontal axis. Are
the loops lined up, or are they at staggered
heights?
__
Steve
KI5YG/EA
..




ps wrote:

I have a photo of an antenna at the Long Marine Labs in Santa Cruz,
California. The view in the photo is to the n-n-west. I'm curious about
what looks like some sort of array of rectangular elements. Is this an
antenna, what type or frequency range? The length of the sides is about
1 meter. I can't post a binary on the newsgroup so the image is
temporarily at this url. http://www.cyberplasm.com/temp/ant_500.jpg

Stephen Cowell wrote:
"Dave Shrader" wrote in message
news:cGhTb.201548$I06.2220041@attbi_s01...

Diversity DF???


Could be a big loop Yagi...the wide-angle
lens has distorted the horizontal axis. Are
the loops lined up, or are they at staggered
heights?

Its not a wide angle lens. They are at varying heights. From the
responses I guess this must be some sort of tracking system for marine
mammal research. Whales, seals, etc. Don't know for sure.

"ps" wrote
Its not a wide angle lens. They are at varying heights. From the
responses I guess this must be some sort of tracking system for marine
mammal research. Whales, seals, etc. Don't know for sure.

Probably vhf, but the clumsiest looking RDF setup I ever saw.

From http://www.ucsc.edu/currents/01-02/10-08/otters.html
sea otters join conservation research project at Long Marine Lab

About 40 wild sea otters have been outfitted with radio transmitters and
temperature monitors.

loop antenna (some on a pcb can look strange - not a loop, but really are)

"DaveC" wrote in message
al.net...
A small transceiver in a wireless security system uses a small square
spiral
solid wire (3 turns?) as an antenna. The frequency is 315 MHz, I think.

What kind of antenna is this? What are its characteristics?

Web references to peruse?

Just curious...

Thanks,
--
Please, no "Go Google this" replies. I wouldn't
ask a question here if I hadn't done that already.

DaveC

This is an invalid return address
Please reply in the news group

A small transceiver in a wireless security system uses a small square spiral
solid wire (3 turns?) as an antenna. The frequency is 315 MHz, I think.

Most of the remote control transmitters use a 1 transistor LC oscillator that
is turned on and off by a digital pulse stream. The spiral on the circuit
board does double duty as the frequency determining inductance for the
oscillator, and acting as a small loop antenna.


73 Gary N4AST