I used similar devices back in the 1960s. I had a weekend/summer job with Technical Trading in Brighton. They used to sell cut price valves.
They bought large quantities of used valves. We tested them using Mullard valve testers (the ones with big punched paxolin cards for each valve type, to select voltages and tests). If OK, we cleaned them off and relabelled them by printing on the side.
If they had low emission, they went into an RF coil that would ignite what was left of the getter. That usually got them to pass the test.
The driving techniques for flat screen were around 40+ years ago. What was missing was the ability to produce small enough plasma cells reliably. The advent of LCD volume production enabled todays screens. CRTs AIUI are still difficult to beat for high brightness/temperatre range displays.
I have DAB in the car. In general, *reception* is far superior to AM or FM in the SE of England.
It's very interesting to ask a DAB hater to tell which recording he is listening to of something simulcast on DAB and FM. Provided you sync them up and match the levels.
I did just that with a chunk of R2 from FM, DAB and FreeView. A panel of
10 'experts' gave almost entirely random results. But I'd guess even they might have heard a difference with AM.
I had a passive colour screen on an early laptop, picture quality was abysmal. Huge amounts of noise & smear, and watching motion was unworkable due to excessive slowness.
No, but the manifestation of them is worse with NTSC than with PAL, in that NTSC suffers drift in the hue whereas PAL just suffers a reduction in saturation without any change in hue.
I remember in the early 1970s my friend's parents had a Hitachi colour TV and it had a tint control (we had fun tweaking it just before his granddad wanted to watch the snooker!). I understand that Hitachi didn't pay the royalty to use a genuine PAL decoder and converted PAL to NTSC and then used an NTSC decoder (or something like that).
I can remember having an old 405-line B&W telly that my grandpa was getting rid of when he got a colour set, and it had all sorts of user-adjustable controls such as frame and line hold, frame linearity, spot wobble - as well as loads more inside near the "tingly bits". Even as a 9-year-old lad, I knew enough not to go anywhere near the inside when the power was on or until I'd run the end of an earthed 10 M ohm resistor across the HT terminals and associated capacitors.
I remember when the "man" came to repair our rented colour TV he let me watch him, providing I kept a safe distance away as he made adjustments while the TV was on, and there was a whole rack of pots that you turned with a screwdriver for tweaking different aspects of the picture. I was a bit young to understand concepts like PAL decoder, colour sub-carrier phase, back porch, sync pulse separation etc and how you used different parts of the testcard to check the adjustment of them :-)
Some of the early colour PC monitors had all manner of esoteric convergence, geometry, rotation and alignment controls. The only difference was that they were accessed from on-screen menus rather than pots. But still plenty to adjust if the picture was blurred or had coloured fringes, and enough interdependence between the different settings to drive you mad. LED screens are so much easier! They are also considerably lighter: my 21 inch CRT monitor was about feet deep and *very* heavy.
Mains valve radios were up and running in 20 seconds.
A lot of modern equipment takes a lot longer than that. Apart from (obvious) computers, TVs and mobile phones have quite restricted functionality, or are very slow to respond, until a lot of background tasks have finished running.
When STD coin box phones came in, they took threepenny bits, sixpences and shillings. They soon blocked up the threepenny slot, so doubling the cost of short local calls.
"Jim GM4DHJ ..." wrote in news:oig5cr$5bm$ snipped-for-privacy@dont-email.me:
The CRT was amazing how it became so good and could be mass produced. Reminds me ot that old Cadbury Smash advert - Aliens laughing as it was explained that electrons would fire through some magnetic coils and through holes in a mask to hit little dots of phospor to make them glow.
Why do modern, but non-smart TVs take so long to start up? You'd have thought they'd be up and running in seconds, but they take ages. What is there to do other than switch on the back-light, clear the memory sync the data stream from the last used input (or start from the next frame when using UHF to ditribute around the house) and start displaying it?
I think it was only in the '80s that they changed the tone received by an operator from a payphone - until then they could not tell them from private phones and people had learned that you could make free reverse charges calls *to* phoneboxes.
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