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Post by bamber on Mar 26, 2019 21:35:42 GMT
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Post by phil70 on Mar 27, 2019 10:24:51 GMT
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
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Post by bamber on Mar 27, 2019 12:58:15 GMT
As an apprentice, I remember a very early test job being given a block of aluminium and being told to FILE it to a perfect 1 inch cube. Maybe thinking back to the result is why I found that movie clip fascinating.๐
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Post by peterboat on Mar 27, 2019 13:32:13 GMT
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
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Post by phil70 on Mar 27, 2019 14:16:34 GMT
As an apprentice, I remember a very early test job being given a block of aluminium and being told to FILE it to a perfect 1 inch cube. Maybe thinking back to the result is why I found that movie clip fascinating.๐ Huh you had it easy, we had to also file a square hole to accept the block. Phil
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Post by JohnV on Mar 27, 2019 14:20:19 GMT
incidentally Phil .... thanks for the explanation
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Post by bamber on Mar 27, 2019 17:16:57 GMT
As an apprentice, I remember a very early test job being given a block of aluminium and being told to FILE it to a perfect 1 inch cube. Maybe thinking back to the result is why I found that movie clip fascinating.๐ Huh you had it easy, we had to also file a square hole to accept the block. Phil It wouldn't have needed to have been square to accept the shape of the block I ended up with Phil. ๐ What I really couldn't understand was why I was filing anything at all when I had signed up for an electronics apprenticeship ๐ค
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Post by JohnV on Mar 27, 2019 17:59:11 GMT
Huh you had it easy, we had to also file a square hole to accept the block. Phil It wouldn't have needed to have been square to accept the shape of the block I ended up with Phil. ๐ What I really couldn't understand was why I was filing anything at all when I had signed up for an electronics apprenticeship ๐ค 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
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Post by Deleted on Mar 27, 2019 19:09:03 GMT
It wouldn't have needed to have been square to accept the shape of the block I ended up with Phil. ๐ What I really couldn't understand was why Iย was filing anything at all when I had signed up for an electronics apprenticeship ๐ค well if you were working on radar in the same era as me, half of that had more similarity to plumbing than electronicsย ย I think I have now thrown it out, but I used to have a quite thick textbook just on waveguide theoryย ย You should have hung onto some of the waveguides too John. Mind you weโve moved on since apparently... rsgb.org/main/operating/band-plans/microwaves/terahertz/
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Post by JohnV on Mar 27, 2019 19:28:53 GMT
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
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Post by phil70 on Mar 27, 2019 23:59:14 GMT
WHOOOOOooosh... the sound of that going straight over my head Phil
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Post by JohnV on Mar 28, 2019 8:22:51 GMT
WHOOOOOooosh... the sound of that going straight over my head Phil 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.
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Post by bamber on Mar 28, 2019 8:57:40 GMT
John, my Ham interest was at the opposite end of the spectrum (literally) to yours. Homebrew QRP CW, although I later got into weather sats from a software decoding angle. But of course it's far easier to just view weather pages on the net these days so I expect that side of the hobby is now defunct. Still got an attic full of kit though.
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Post by JohnV on Mar 28, 2019 9:10:45 GMT
John, my Ham interest was at the opposite end of the spectrum (literally) to yours. Homebrew QRP CW, although I later got into weather sats from a software decoding angle. But of course it's far easier to just view weather pages on the net these days so I expect that side of the hobby is now defunct. Still got an attic full of kit though. 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$%&$ยฃd opens up near you with a few kilowatts.
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Post by Deleted on Mar 28, 2019 9:19:57 GMT
WHOOOOOooosh... the sound of that going straight over my head Phil Good old CB days! Iโve still got friends I met through that in the 80s. CB is still active. Mainly older people now and a few truckers. Many of them also have a ham licence and use CB for general local chat. I wonder if Stabby had one? They have changed things now so you can legally use SSB at 10w I think. Thatโs more than QRP (5 watts) so you have a good chance of taking to Europe or the States now if the conditions are good. The ham licence changed many years ago too. There are 3 levels now. They are multiple choice ;with a few practical tests in the first 2 levels). The foundation licence limits you to QRP (5 watts), intermediate to 50 watts and advanced to full power (and a couple of other perks like working the 5Mhz band. The foundation course really is easy if you can do very basic maths and remember very basic electronics.
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