UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Specific Vintage Equipment > Television Standards Converters, Modulators etc

Notices

Television Standards Converters, Modulators etc Standards converters, modulators anything else for providing signals to vintage televisions.

Closed Thread
 
Thread Tools
Old 7th Dec 2005, 1:33 pm   #21
ppppenguin
Retired Dormant Member
 
ppppenguin's Avatar
 
Join Date: Dec 2003
Location: North London, UK.
Posts: 6,168
Default Re: 405 line recording.

Well worth trying a B&W mode if one is available.

Slightly OT, I've got a couple of older VHS machines hanging around doing nothing. AFAIK they both work but I haven't tried them for several years. They are Fergy Videostars, clunky push button electronic controls. Not sure which model but they're the right sort of age to be OK with 405. 10 each or 15 the pair but I really wouldn't want to pack and ship them. Collection from North London or some kind of arrangment if a kind person is headed in the right direction.
ppppenguin is offline  
Old 7th Dec 2005, 2:13 pm   #22
peter_scott
Dekatron
 
peter_scott's Avatar
 
Join Date: May 2003
Location: Edinburgh, UK.
Posts: 3,249
Default Re: 405 line recording.

Quote:
Originally Posted by channel405

The tape differences shouldn't make a difference, I think this is a playback phenomenon rather than a recording issue.

Tim
Hi Tim,

Again, I haven't looked to see how SVHS differs but the recording is certainly different because an ordinary VHS machine can't play SVHS tapes. I think you'll find that your SVHS machine will sense whether or not to record in SVHS mode by the hole pattern on the cassette base.

Peter.
peter_scott is offline  
Old 7th Dec 2005, 3:54 pm   #23
channel405
Tetrode
 
channel405's Avatar
 
Join Date: Jun 2004
Location: CH3, Blaen Plwyf Transmitter, Aberystwyth, WALES
Posts: 72
Default Re: 405 line recording.

Hi Peter

Yes thats right about the hole in the cassette activating the switch between both recording formats. SVHS machines are backwards compatible with VHS. The main difference is wider FM deviation for higher Y bandwidth (about 400 lines instead of 240) and wider for chroma. Y and C are kept apart through the whole signal processing hence the seperate connections. The pic quality is only slighlty better though because noise remains quite high despite denser tapes (metal?) and drum/tape speed is still quite low compared to Beta SP etc. Still its good enough for 405 lines, apart from the ghosting thing of course!

Tim
channel405 is offline  
Old 7th Dec 2005, 6:25 pm   #24
oldeurope
Retired Dormant Member
 
oldeurope's Avatar
 
Join Date: Dec 2003
Location: Solingen, Germany
Posts: 727
Default Re: 405 line recording.

Quote:
Originally Posted by channel405
Hi Peter and all,

Daruis, thanks for your suggestion about the back porch with Umatic recordings. But if I remember the original 405 spec didn't include a porch before the H pulse, and as the camera I used is of 1966 vintage I don't know if the camera would be generating one.
Tim
Hi, I am born in the same year as your camera.
In the british standard it is 0.5us before the H-pulse begins and app. 5us
after the end of the H-pulse.
You can see it on the oscilloscope. But from your pics this is not your
problem. Vision in the flyback looks different.

Darius
oldeurope is offline  
Old 7th Dec 2005, 6:28 pm   #25
oldeurope
Retired Dormant Member
 
oldeurope's Avatar
 
Join Date: Dec 2003
Location: Solingen, Germany
Posts: 727
Talking Re: 405 line recording.

Quote:
Originally Posted by peter_scott
Hi Tim,

Again, I haven't looked to see how SVHS differs but the recording is certainly different because an ordinary VHS machine can't play SVHS tapes. I think you'll find that your SVHS machine will sense whether or not to record in SVHS mode by the hole pattern on the cassette base.

Peter.
Hi Peter, drill a hole in your standard VHS-tape and try to make recordings.
If you have a good tape you'll get success and save money hi hi.

Darius
oldeurope is offline  
Old 7th Dec 2005, 6:32 pm   #26
Heatercathodeshort
Dekatron
 
Heatercathodeshort's Avatar
 
Join Date: Jun 2005
Location: Warnham, West Sussex. 10 miles south of DORKING.
Posts: 9,122
Default Re: 405 line recording.

Hello,
I have checked the speed of the video head on both 405 and 625 and you are correct, it is the same and of course must be! I had checked it visually at first and by the sound of the head. It never fails to amaze how you can convince yourself of the impossible! I ended up sticking a small square of reflective tape onto the drum and using the head off a truck tacho tester proved that they were the same. The garage guys thought I had gone off my rocker....The two readings were identical but were in MPH rather than RPM. Thanks for putting me right on this issue. Regards JOHN.
Heatercathodeshort is offline  
Old 7th Dec 2005, 11:59 pm   #27
channel405
Tetrode
 
channel405's Avatar
 
Join Date: Jun 2004
Location: CH3, Blaen Plwyf Transmitter, Aberystwyth, WALES
Posts: 72
Default Re: 405 line recording.

Hi Darius,

Yes you are of course quite right about the presence and duration of the porch on the 405 waveform, I have just consulted my 1949 "Priciples of (405 Line) Televsion". I was sure that there was something like a porch that 405 never used but 525 and 625 did, could I be thinking of equalising pulses? Or am I just talking jiberish?!

I must point however the pics are from a VHS tape were kindly recoreded for me and not from the Sony 405 camera. The camera footage is on a Umatic tape and I will get a pic of that as soon as I locate the tape.

Tim
channel405 is offline  
Closed Thread

Thread Tools



All times are GMT +1. The time now is 5:57 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2023, vBulletin Solutions, Inc.
Copyright ©2002 - 2023, Paul Stenning.