Do You Remember?
The Time Tunnel digital audio delay system offered a
broadcast-quality, six-second audio delay that used a digital memory
system to provide consistent audio reproduction. Unlike tape delay
systems, it had no moving parts to wear, no preventative maintenance
was necessary and the performance did not degrade with time.
The Time Tunnel was offered in two models: the TDG-1 with a 15kHz
bandwidth and the TDG-2 with a 7.5kHz bandwidth. Both models created a
frequency response flat within 0.25dB and a total harmonic distortion
of less than 0.5 percent. They offered an operating range of greater
than 66dB with a clipping level of 12dB and a system signal-to-noise
ratio of greater than 80dB.
That was then
This is the radio transmitter room of KPO in Hale's Department
Store, San Francisco, in 1925. Shown in the foreground is the Western
Electric 1kW model 6A transmitter. In the background are marble-faced
electrical control panels, which at the time were the only ones of
their kind in the country.
The KPO employee inspecting the transmitter is probably Claire
Morrison, KPO's first full-time announcer. The transmitter was a newer
design and unlike earlier transmitters, it was capable of 100 percent
modulation. By this time, most stations were assigned to their own
frequencies and transmitted for significant portions of the day. KPO is
now KNBR, San Francisco. Photo courtesy of Bill Ruck, KNBR.
Sample and Hold
A look at the technology shaping radio
What do talk-radio listeners do while listening to the radio?
Source: Scarborough Research, Release 2 2001