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| Re: Remember TV Test Patterns? (252464) | |||
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Re: Remember TV Test Patterns? |
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Posted by tracksionmotor on Wed Oct 10 01:27:20 2007, in response to Re: Remember TV Test Patterns?, posted by SelkirkTMO on Tue Oct 9 23:58:15 2007. Per FCC regulations, hams had limited transmission bandwiths. Before slow-scan frame video in a AFM format (shortwave), there was 'spot scanners' that placed a transparancy between a kinescope and a photomultiplier tube...you could transmit a single NTSC frame on the UHF bands. It would be many years before affordable vidicon cameras availed hams for TV.....the TV receiver format is identical to NTSC and slightly modified TVs with preamps. One evening I received a UHF TV repeater underneath the Brooklyn Bridge thinking it was TV Pirates until I heard ham callsigns.'Spot Scanner' was TV engineering staple....unlike a 'monoscope' you could change the image by changing the tranparancy without burning in an image into an expensive tube....Hickock manufactured a unit that looked like a toob tester you could drop a slide into for a B/W image. There was nothing digital in those dayzzzz.....test pattern including an 'Injun' was straight analogue.....monoscope had everything built in including a fixed test image. Hickok produced one of the first color bar generators....a 'gated rainbow'.....not a NTSC color bar pattern....but far better than anything not yet available to adjust color convergence. BTW: Don't knock spot scanners. In post war TV, programming not live was on motion picture film using 'chain film scanners' that encoded image into analogue video for transmission on AM vestigial sideband and audio for FM transmission....AM and FM combined into a diplexer.....YOU should know that better than me! All that violent video we grew up with...Gas House Gang, East Side Comedy, Abbot and Costello, THREE Stooges....were all film chain transmissions. I did radio repair for ABC local news when cameras were motion picture film and they had a fleet of Harley Davidson motorcycles with press permits. Just before my Dayton trip I discovered the Olympus OM-10 I bought my mom. There ia film in it. At Dayton I got a Olympus 135mm lense...I should have bought the 50mm macro too but did not. Problem is that I used to shoot off 36s but it could be a 24....don't know which way to turn! |
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