One for the engineers among us

Yes I do like this. Good example that demonstrates the phenomenon of what I was taught was called wringing.
By having super flat and super smooth surfaces the two parts are held together by a combination of air pressure and molecular attraction.
Phil

Modern conrods on engines are machined in one piece then the big end part is broken in two, apparently it makes a better joint! amazing stuff

incidentally Phil .... thanks for the explanation

well if you were working on radar in the same era as me, half of that had more similarity to plumbing than electronics  



I think I have now thrown it out, but I used to have a quite thick textbook just on waveguide theory  

bloody hell Terahertz !!! I was working on 10cm, 3cm and 1.5cm as marine

Bloody hell that's about one millionth of the wavelength of our shortest wavelength marine stuff

We thought we were hot stuff working on 144 Mhz with homebrews and helical aerials for OSCAR

terahertz goes over mine as well Phil ..... the last bit ..... Homebrews   Home built transmitters and receivers (very little commercially available for those amateur frequencies although military/marine/aircraft stuff was available to be modded) and Orbiting Satellite Carrying Amateur Radio the first one was launched in the early 1960's ....... although it only lasted about 3 weeks, it helped me get even more interested in radio and helped the decision to go into radio/electronics as a career.

The Americans launched them, piggybacking them onto their own payloads, as a result the orbits could be odd. 
They had to be built to a specific size and weight and were used to balance the (often military) payloads for other launches. As a result the orbit you got .... was the orbit you got.

The college amateur club station (not me operating unfortunately .... but I was in the room) managed a link to Oscar III on 144Mhz to a Swedish amateur but only for a few seconds.  It was a pity but the transponder in that satellite stopped after quite a short time (a couple of weeks or so)
Later the same year there was another Oscar launch and we had massive problems constructing the downlink receiver as that was 432Mhz.  then after all that work and effort ..... the rocket had a fault during launch and put it into an extremely low orbit making it almost impossible to use.

That was my last experience with OSCAR as the next launch wasn't until 4 or 5 years later (the Australian Oscar if I remember right) and by that time I was at sea. I let my amateur licence drop shortly after as my interest in working stations waned after doing it for a living, and anyway I think it was working out ways of constructing or modifying kit for special purposes that used to really get my interest.

Aaah !!! a member of the million miles per watt club ...... I was expected to provide world wide communication at any time with a measley 60 watt CW transmitter ...... My hats off to you, I know the frustration of trying to get through to a distant station when some b$%&$£d opens up near you with a few kilowatts.