I have 5 of these little tubes all NOS. What are they used for . This really intrigues me . They are tiny tubes with no base on them but 4 long wires. Photos sent.

Hearing aid tubes?

High frequency triode. Characteristics here:

https://frank.pocnet.net/sheets/138/5/5676.pdf

Looking at the specifications for that tube, its and oscillator with the range of 100 to 350MHz.

My guess is 2 way handheld.

GTC - beat me to it on the datasheet... Wow a whole 100hrs life!

They were just a nice little find in my booty from the last Canberra meet.

They were intended for WW2 proximity fuzes.
100 hours is more than enough life - they only have to last from when the shell was fired from the gun until it approached its target.

Incredible bit of technology for 1940s - a doppler radar in the head of an artillery shell. If you were shooting down planes you didn't have to hit them, just get close. Without this technology, it took an average of 80 AA rounds to score a hit on an aircraft The Proximity Fuze reduced this to less than 5 in many cases.

Best kept secret weapon of WW2, had more impact on the course of the war than is generally known. For example:

1. Stopped Hitler sending (manned) planes to bomb London
2. Allowed the shooting down of the flying bombs.
3. Was responsible for the failure of the Kamikaze program in the Pacific.
4. Caused the German troops to revolt during the Battle of the Bulge (when used for air bursts)


A very large number of people worked on the development and manufacture, despite this, the secret was kept. Only released in 1968. Someone should make a movie about it!

The main fellow that developed this equipment was a Aussie . There was a fairly large article on him in the HRSA Radio Waves Magazine. I feel lucky to have these little gems.

The research and development effort for proximity fuses was the next biggest effort after the atomic bomb, and cost about 25% of the bomb.

Heard another feature of this was that the battery was activated when the shell was launched. That the shell rotated, and a weight would crack a vial that allowed a liquid to fill the battery which in turn activated it and then the tube would then come to life. The tube would have to be durable enough to take the rough handling of being shot out of a canon, but it didn't need survive the shell blowing up... Actually, you'd want it not to, so the enemy can't reverse engineer it.

Quite a bit of proximity fuze documentary footage on YouTube. Here's one:

https://www.youtube.com/watch?v=Kq_Uy5hGazc

And here's a later British one about manufacturing the assembly:

https://www.youtube.com/watch?v=GMlHZ4Wy2yw

Yes Wa2ise, the battery idea was a great example of using something you really don't want (the g force when fired out the barrel) to your advantage. Brilliant!

It was also done to extend the shelf life of the fuzes. Also, the resultant startup delay from that and the thermal inertia of the filaments was enough to ensure the shell was well and truly clear of the barrel before it became active.

There are many amazing innovations in these things, to do so much with so little.

As you said STC830, it was the 2nd most expensive R&D effort of WW2 and the secret was much better kept!

I haven't read it, but there was a book on the proximity fuze called "They never knew what hit them".

Wow I found some very interesting pictures on the net last week . One of them is to do with the tomahawks that Trump sent to Syria last week. I have sent the pics to be uploaded. Have a geezer at these.

At least it should stay on tune lol. without drifting.