XPost: alt.satellite.tv, alt.satellite.tv.australasia, alt.satellite.tv.europe   
   XPost: rec.radio.shortwave, rec.video.cable-tv, rec.video.satellite.misc   
   XPost: rec.video.satellite.tvro, sci.engr.radar+sonar, uk.tech.broadcast   
   From: junk@junk.com   
      
   "Steve Roberts"  wrote in message   
   news:3f0ac941.25351983@news.reith.bbc.co.uk...   
   > On Tue, 8 Jul 2003 13:11:24 +0100, Nigel Goodwin   
   >  wrote:   
   >   
   > >You couldn't record 405 line on a 625 line recorder, it wouldn't work,   
   > >there were no domestic 405 line VCR's made (it was too early) but   
   > >commercial machines were available.   
   >   
   > Au contraire on both counts, Nigel!   
   >   
   > You most certainly can record and replay 405 line TV on a domestic 625   
   > line VHS, because I've done it! The field period is 20mS on both   
   > formats, so the rotary heads spin at the same speed. The VHS doesn't   
   > mind how many lines are included in that period.   
      
   Exactly the point that I was making: I'm glad someone's come to my defence   
   and convinced me that I wasn't making it up!   
      
   > There were domestic 405 line reel-to-reel VTR's - the Sony CV2000   
   > being the most well-known and popular one. You could buy a matching   
   > monitor and camera for it, to allow you to go out and shoot your own   
   > videos.   
      
   I remember this: I think it recorded on 1/4" audio tape - it certainly   
   *looked* narrower than 1/2" VHS tape, but I could be wrong. The VCR had a   
   very obvious circular cover over the head, with a semi-circular guide around   
   which the tape was wrapped. Stability of the picture was atrocious: at best   
   the picture wobbled and shimmered - and if you breathed on the VCR (let   
   alone jogging it or carrying it), the picture broke up completely.   
      
   > > The BBC originally used to convert   
   > >between standards (405/525/625) by playing it back on a monitor and   
   > >recording from a camera aimed at the monitor.   
   >   
   > That was true of very early 525/625 conversions, but not 405/625, as   
   > this could be done using simple electronic line stores and averaging,   
   > even in the early days.   
      
   That must have resulted in *horrible* moire fringes and 5 Hz flicker. I'm   
   too young to remember it being done - I presume nowadays that if any very   
   old 525 material is shown, it is converted a lot more professionally so one   
   would never see the effect nowadays.   
      
   Was there a simple relationship between the number of active lines for 405   
   and 625? Certainly 405/625 isn't a simple fraction. I'm not sure how many   
   active lines the 405 system had.   
      
   --- SoupGate-Win32 v1.05   
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