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   From: stephen.neal@as-directed.com   
      
   On 12/7/03 4:11 pm, in article 3F10251F.AD626882@yahoo.co.uk, "The Technical   
   Manager"  wrote:   
      
   > Steve Roberts wrote:   
   >   
   >> 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.   
   >   
   > Older VHS video recorders can handle 405 line material with few problems.   
   > The Ferguson Videostars or their JVC equivalents are good choices. Around   
   > 1988 there were changes in circuitry that prevent them from properly   
   > recording and playing back of 405 line material. Possibly something to do   
   > with Macrovision.   
      
   Don't think it was related to Macrovision - I think it was the introduction   
   of VHS HQ.  This uses line-delay techniques to "improve" the picture - and   
   as they line lengths are different in 405 and 625 it doesn't cope with 405   
   at all well.  Personally I'm not sure HQ improves decent recordings at all -   
   it just seems to add artifical ringing-style edge...  Certainly some of the   
   best pictures I have seen from a VHS VCR were recorded on an early 80s   
   Hitachi machine (first generation with electronic rather than piano key   
   controlled transport?)  I suspect build quality and specs were higher then   
   (but then the machines cost massively more in relative terms?)   
      
   Even non-HQ VHS machines had problems with 405 recordings with drop out - as   
   the drop-out comps in VHS machines were based on line-delays (designed for   
   625 line recordings)  Therefore drop-out comps made 405 recordings worse not   
   better. (I think 405 enthusiasts either use high quality tapes or disable   
   the DOCs on their VCRs?)   
      
   I wonder if anyone has produced a Video CD style MPEG recorder for 405 lines   
   ? With more data available (no colour content) it could look quite good?   
      
      
   Steve   
      
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