Here's a tale of geekery that I stumbled across yesterday morning. It belongs over at Retrotechnologist but I'll debut it here. Though it's about radio and TV broadcasting here in Indiana, the story begins in Turkey.
The principal of the tale was Armenian. He was born in 1900. It was a bad time to be an Armenian in Turkey, and getting worse; his father saw this and in 1907, took the family to the United States.
Sarkes Tarzian grew up with the infant science of radio and was a bright student; out of college, he worked for Atwater-Kent and, eventually, RCA. He was a good engineer and a master of cost-effective designs. When WW II ended, the 45-year-old engineer found himself in Bloomington, Indiana, at an RCA plant already back to building consumer radios, much like the Atwater-Kent factory where he'd started out.
Rather than go back to the grind, he hung out his own shingle, a consulting engineer. FM broadcasting was just getting started back up, settling into the new band RCA had managed to get it nudged into, but receivers were expensive. The new mode didn't use spectrum as efficiently as AM, either -- and that left an opening for a sharp engineer: "All-American Five" AC-DC radios for the AM band were cheap to build -- and, if you knew what you were doing, cheap to convert to the FM band. Detecting FM required plenty of additional, expensive parts -- but if a station transmitted an AM signal, the AA5 would do the job. In early 1946, Tarzian put amplitude-modulated W9XHZ on the air on 87.75 MHz, built scores of up-converters into ice-cream tins so existing radios could pick up the station, and modified a few dozen "generic" AA5s built at the not-too-distant Meissner plant (Mt. Carmel, IL) as fix-tuned receivers. It worked.
However, the experiment had already been tried. In the late 1930s through early 40s, "Apex" stations transmitting AM on frequencies from 24 MHz up through 50MHz had been on the air. They worked, too -- but Major Armstrong's FM system worked better. TV was starting to grow and by May, 1949, it had come to nearby Indianapolis: WFBM-TV was the first, on channel 6. The sound carrier -- FM! -- for channel 6 is, oops, 87.75 MHz. The FCC required Tarzian's station to shut down any time channel 6 was on the air and when the license (for by-then KS2XAP) ran out, that was the end.
If you can't beat them, join them: Sarkes Tarzian and his crew got their own TV license (and a regular AM-band station, too, WTTS) and by November of 1949, WTTV was on the air on Channel 10, with a transmitter and antenna built at the Sarkes Tarzian factory. Five years later, they moved to channel 4, put up a tall tower midway between Bloomington and Indianapolis, and went head-to-head against channel 6. Little love was lost between the two; noting that transmitter problems had put WFBM-TV off the air for an extended period of time in 1949, WTTV promoted themselves as "Indiana's oldest continuously-operating TV station" for years afterward.
Sarkes Tarzian got into the consumer side of television early on; realizing the tuners were the trickiest part of building a TV set, he designed his own sturdy, inexpensive version and built them in bulk for many manufacturers. TV station WTTV was built with TV-tuner money!
...That's the story of how central Indiana had, for a few years, an FM-band station that wasn't FM.
BUILDING A 1:1 BALUN
1 month ago