timz
Topic Author
Posts: 6579
Joined: Fri Sep 17, 1999 7:43 am

What's This? ("meteorological Equipment" SFO 1967)

Fri Oct 16, 2015 1:30 am

 
barney captain
Posts: 2299
Joined: Tue Nov 06, 2001 5:47 pm

RE: What's This? ("meteorological Equipment" SFO 1967)

Fri Oct 16, 2015 1:45 am

Wow, absolutely no idea - interesting find.

It looks like something that would fire a laser.....


http://www.whatsageek.com/wp-content/uploads/2014/12/Dr-Evil.jpg
Southeast Of Disorder
 
tribird1011
Posts: 214
Joined: Mon Mar 14, 2005 10:08 pm

RE: What's This? ("meteorological Equipment" SFO 1967)

Fri Oct 16, 2015 7:49 am

Although it seems "fancy" my guess is a wind measuring device (speed/direction) -- only a guess though  
 
WIederling
Posts: 9305
Joined: Sun Sep 13, 2015 2:15 pm

RE: What's This? ("meteorological Equipment" SFO 1967)

Fri Oct 16, 2015 3:59 pm

Quoting tribird1011 (Reply 2):
only a guess though

The part pointing away from the viewer is a helical antenna. The plate with radials the reflector.
I'd guess the diameter is around .5m? that would fit ~300MHz ?

I can't make anything out of the two "thingies" projecting towards the viewer.
they seem to be movable up and down.
Murphy is an optimist
 
jox
Posts: 119
Joined: Fri Jan 03, 2003 3:39 am

RE: What's This? ("meteorological Equipment" SFO 1967)

Tue Oct 20, 2015 6:35 am

I asked some radio amateur friends. They thought it is a helical antenna that is (was) used to listen to weather balloons. The "fins" at the back are probably counterweights of some sort that also takes the wind load that otherwise would try to rotate the antenna. The reason that they are pointing in different directions is probably that they shouldn't block each other regardless of wind direction.
 
timz
Topic Author
Posts: 6579
Joined: Fri Sep 17, 1999 7:43 am

RE: What's This? ("meteorological Equipment" SFO 1967)

Tue Oct 20, 2015 9:30 pm

Do airports still use weather balloons? If not, what has replaced them?
 
WIederling
Posts: 9305
Joined: Sun Sep 13, 2015 2:15 pm

RE: What's This? ("meteorological Equipment" SFO 1967)

Tue Oct 20, 2015 9:56 pm

Don't know about airports.

But the National weather service ( Germany, Europe in general?)
still does start ballons on a regular basis:
http://www.radiosonde.eu/RS00-D/RS02H-D.html#ancre220984

I've visited Schleswig Wetterwarte ~15 years ago.
They had a start at noon and at midnight each day.
( Seem to still do so going by my link.)

Afair the tracking antenna ( via the radar reflector on the payload ) there was a parabolic mirror.
Can't remember what they used for data reception ( ~400Mhz).
Murphy is an optimist
 
Viscount724
Posts: 19316
Joined: Thu Oct 12, 2006 7:32 pm

RE: What's This? ("meteorological Equipment" SFO 1967)

Wed Oct 21, 2015 12:44 am

Quoting timz (Reply 5):

Weather balloons are still in widespread use. This video is a year old.
http://www.youtube.com/watch?v=UUe8KyIEfrU
 
PSAjet17
Posts: 375
Joined: Thu Dec 11, 2003 5:50 am

RE: What's This? ("meteorological Equipment" SFO 1967)

Wed Oct 21, 2015 4:02 pm

Quoting timz (Reply 5):
Do airports still use weather balloons? If not, what has replaced them?

Yes they launch from 102 sites in the US.
http://www.ua.nws.noaa.gov/factsheet.htm
 
timz
Topic Author
Posts: 6579
Joined: Fri Sep 17, 1999 7:43 am

RE: What's This? ("meteorological Equipment" SFO 1967)

Wed Oct 21, 2015 5:11 pm

Do those 102 sites have helical antennas like the one at SFO? If not, what instead? Anyone seen circa-1967 pics of antennas like that at other airports?
 
nikeherc
Posts: 670
Joined: Thu Sep 13, 2012 8:40 pm

RE: What's This? ("meteorological Equipment" SFO 1967)

Wed Oct 21, 2015 5:42 pm

It is a helix or helical antenna. The flat plate is not actually a reflector, but is the antenna ground plane. Helix antennae have good gain and are quite directional. The structures behind the ground plane are counter weights.
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