[SBE] Cert Q 4

[A9xw at cs.com]

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!