What's this metal thing?

January 28, 2015 9:08 PM

I came across this cute metal thing in a closet and have no idea what it's used for. It's like a three dimension capital I. A magnet doesn't stick to it. Dimensions are about .75"x.75"x1". It weighs 1.5oz, which seems heavy for its size and the fact that part of it is hollow. Photos inside!

Sitting on its end
Sitting on its side, with slot visible. The slot is an opening into the hollow post.
Top view
Alternate view There is a square cover on one end fastened with two allen bolts diagonal from each other. The other corners are empty bolt holes.

posted by oxisos to Grab Bag (6 answers total)

Best answer: It's a piece of waveguide, dunno why it's in your closet though. The cover looks homemade.
posted by Confess, Fletch at 9:16 PM on January 28, 2015 [5 favorites]

To be a little more specific, it looks like a waveguide from a airborne radar system. You could measure it and figure out what frequency range it's designed for and then make a fairly good guess as to what it's from.
posted by Confess, Fletch at 9:25 PM on January 28, 2015

Best answer: Yup: Waveguide, almost no question about it. Haven't used one of those in anger for 20 years :)

What are the hole measurements?
posted by pharm at 2:08 AM on January 29, 2015

Response by poster: The unthreaded corner holes on the non-covered side are 3mm in diameter. The threaded corner holes on the covered side are 2mm. The rectangular slot opening is 11x4mm. Does that help narrow down the use?
posted by oxisos at 8:48 AM on January 29, 2015

Best answer: Definitely a piece of waveguide, probably WR-42 ("K band"), for the 18-26.5 GHz range.

Whoever lived in your place last was either a ham radio operator with a passion for rather high frequency equipment, or a microwave engineer, physicist, or member of a similar occupation who brought their work home with them.

Any idea who lived there last? Are there patched holes in the roof where antennas used to be mounted and cables routed?
posted by eotvos at 9:56 AM on January 29, 2015

Response by poster: Actually, we had a physics grad student (who worked in a machine shop) living here recently, so I will ask her!
posted by oxisos at 10:07 AM on January 29, 2015