[SBE] Cert Q 4

[Wilson Brown]

This is truly turning into a fun day.

In the 1930's my Dad worked transmitter shifts at an experimental TV station run by WMAQ in Chicago. They transmitted just above the AM broadcast band and used a Nipkow mechanical disk to scan the picture. Source material was rough cartoon drawings sketched by an artist sitting at a drawing board. They published details in the Chicago papers on how to modify a standard AM radio to get up to the experimantal transmissions and how to use a neon bulb and mechanical disk to create a "picture" of sorts on a ground-glass screen. Picture size was about 1 x 2 inches. (Sounds like a cell phone doesn't it?)
 
Best Regards,
 
Louis Brown
(508) 294-5869



----- Original Message ----
From: "A9xw at cs.com" <A9xw at cs.com>
To: sbe at sbe.org
Sent: Thursday, November 15, 2007 2:59:19 PM
Subject: Re: [SBE] Cert Q 4

Its a trick question.  15/7.5 for quad FORMAT tape,  A 10 mil head for 15 ips 
and 5 mil for 7.5.  (also a 15 mil notched to 10 and 7.5 notched to 5) Lots 
of stations used the 5 mil Mark 3, mark 10 (and RCA equivalent) since you could 
double the record time on the $200/hr tape stock. 
Linear recorders, few of which ever reached the market used speeds to 120 
IPS, but lacked TBC's and didn't do color. But ... early TV over radio, used 78 
RPM records to record the "audio" rate signal of the very low rez video 
signals, similar to slow scan TV used on ham radio. The disks could be recorded with 
the aural portion of the program and the visual, often just a still of the 
orchestra which was transmitted over a handful of AM radio stations in the 20's 
and 30's. Spinning disk technology  to compliment the Nipkow spinning disk!  
_______________________________________________
SBE mailing list
To unsubscribe, go to http://seven.pairlist.net/mailman/options/sbe
_______________________________________________
SBE at sbe.org
http://seven.pairlist.net/mailman/listinfo/sbe