Any idea what this might be?
https://www.ebay.co.uk/itm/absolute...086144?hash=item1a810a4f00:g:HAgAAOSwm~hdPa3l

 

Looks like some sort of wave guide on image 3, 4 and 5?

Would be interesting to see a view on the top of the "lamp".

 

Looks like some sort of wave guide on image 3, 4 and 5?

Would be interesting to see a view on the top of the "lamp".

Pretty much reflects my first thoughts. It seems strange to have those two long wires inside the glass and not much else (looks like a couple of sockets on the top but I don't think that's likely).

 

Not sure of the physics but could it be some sort of indicator to show that microwave energy is present?

Does the US sign with anchor mean anything?

Made for US navy?

 

its not just some kind of light or signal light for a old boat?

 

I think this picture shows the tungsten filament near the top , just above that is an inverted bowl shaped piece of metal for reflecting the light down onto the parabolic dish in the spot light itself ...Anchor suggests its a replacement bulb for a boat spotlight ...halogen. Probably the round part to the right in the picture and facing away is where it was connected to the boat allowing turning about an axis to aim the light up and down .. the wires probably exited there

Here's a modern equivalent .. the metal bowl has been replaced by a metal coating on the inside of the quartz , painted black on the outside , presumably to radiate heat more effectively...

 

Ionization vacuum gauge, aka hot filament or hot cathode vacuum gauge?
Just guessing.

 

Old style microwave power meter. A later version of pointing the output of a radar system at an automobile's headlight to measure power.

 

I agree with microwave, that looks like a feed tube, the bulb might have been filled with fluorescent gas to indicate microwave power. It looks like it could be slightly dangerous.

 

The glass bit is bolted to the metal plate and that plate has holes round the edge like something was bolted over the top of the glass bit.

 

I think this picture shows the tungsten filament near the top

I can't see anything that might be a filament. Could you point out where this is.

 

There seems to be quite a chunky hex nut inside, at the top of the glass envelope. Unclear what that would hold in place. Stud rectifier perhaps?

 

This is another shot from the listing... my guess would be some sort of shielding

 

It is odd. The metal rods inside are hooked to a top metal plate and in one picture it appears there is a smaller nut above where one rod hooks into the upper plate. Glass bowl fastened down to a mounting flange with a metal plate on top of it being held down by a pair of small rods and the metal plate on top of the bowl has two pieces of metal tubing with nuts on the ends of the tubing inside the bowl. Cast frame it is attached to has a double elbow with a rectangular opening with the flat mating surface but no visible means of connection. The rectangular opening seems to be made of a different material than the casting. What appears to the central casting has metal plates riveted to the outside holding the assembly together. Quite an intricate assembly and strange indeed. The anchor and US insignia are not typical US Navy markings although definitely appears nautical?

 

Could also be a transition from a dipole antenna to waveguide. A twinlead plugs into the top and comes out to the waveguide. Posting on ebay really has lousy pictures that go nicely with its lousy description.

 

Hello,

Have a look at page 11 of the document:
https://docplayer.net/53648178-Magnetron-tubes-cyclotron-type-magnetrons.html

Western Electric 725A is a classic X band radar tube from World War 2 - a Western Electric 725A magnetron! This early tube was used in quite a few aircraft radars of the 1940s and 50s.

Bertus

 

Nice find @bertus

 

I can't see anything that might be a filament. Could you point out where this is.

Follow up photos show what I thought was a filament is not ....

This is a strange one . Looks like the two nuts are sealed within the glass !

I'm sure if we could get our hands on it we could figure it out ...

Who wants to buy it ??? ...Opps too late .. bidding has closed , only one bid , buyer paid 5 pounds.

 

Yes ... Burtus cracked it ... here's a similar but not identical on one ... 2 Raytheon 2J49 tube (USN WWII Radar magnetron)+ 206 EY https://www.worthpoint.com/worthopedia/2-raytheon-2j49-tube-usn-wwii-radar-magnetron-+-206

And a youtube of one ...

 

@bertus got it right.

Google Western Electric or Raytheon 725A magnetron.

http://physicsnostalgia.com/Magnetron/Mag_pg/magnetron_pg.html

https://www.ebay.com/p/Vintage-Western-Electric-Electron-Tube-725A-Magnetron-Untested/1352532186