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Re: [ARSCLIST] OTR online?

Hi Steve, Bob, Anthony, Robert, et all.

I bit more info on real hi end AM and FM radio performance from the Golden Age. By the end of the 1930s around 1940, E. H.. Scott Labs (no relation to H. H. Scott) was making some extraordinary radios. AM could have wide bandwidth when circumstances permitted. In these earlier times, the AM band was not cluttered with a lot of stations which tended to interfere with each other. In those days there were fewer stations with lots of power and clear channels. They also usually were limited to daytime operation because interference went up at night due to atmospheric conditions.

When the AM band got crowded (in the 1960s? or later), receivers had to have 9KHz or 10KHz audio filters to help reduce increasing man made noise issues and station reception interference. AM noise in car radios from the ignition systems raised havoc with reception, not to mention the mechanically noisy acoustic car environment. When the filters went in and the AM band got crowded, then received AM fidelity really went down even though the AM transmitter could still transmit wide band audio. Also in earlier times, there was a real emphasis on quality. Later on, music sources had their sound manipulated by processors in the recording studio and also more signal processing at the broadcast station to be louder and also attempt to reduce various noise issues and sound well on cheap AM radios of limited performance. Sound quality music reproduction reception moved to FM for obvious reasons.

Back to the story. In 1940, E H. Scott, who called themselves 'The Stradivarius of Radio Receivers', made a "Philharmonic Receiver" that had 5 bands, including the new
Armstrong FM on its original frequency band of 41 to 50 Mhz. The set had 33 of the large big pin tubes and came with a 5 year parts warranty. The frequency response of the
AM section was the same as the FM section, 30 to 15KHz. It had variable IF Bandwidth to adjust for reception conditions. The AM antenna was adjustable for gain, nulling,
pick up pattern, and was highly shielded against local interference. There were tube voltage regulators to keep the tuner from drifting off station. One could order 8 different cabinets,
woods, colors, etc. and there were options of speakers, amplifiers, etc. The circuits had multiple Mixers, RF amplifiers, IF Amplifiers, Detectors, AGC, AVC, Tuning Eyes, an 8 tube Audio Amplifier, Noise suppressor for suppressing 78 record surface noise, separate power supplies with high filtration, dual tuning speeds, etc., a 4 speaker option, a sensitivity of
.5 microvolts, logging scale, muting between stations, etc. It used dual chassis construction of 14 gage chrome plated steel. If memory serves, In 1940 this radio cost between $3000.00 to $4000.00! Think of that in today's dollars. It was the best of the best. Many musicians and those with deep pockets owned these E.H. Scott sets. It was one of the few
equipment items that got a rave review from Toscanini who said "Never would I have believed it was possible to attain such marvelous reproduction... the quality of tone is mellow,
clear, beautiful, and not confused as in other receivers which I have had before yours. To you assuredly belongs the credit of having produced a miracle of perfection."

Then World War II put it all on hold due to the war effort, etc. After the war, the FM frequency band was changed from the better lower 41 to 51 MHz band to the higher current 88 to 108 Mhz band due to the Armstrong and RCA (Sarnoff) patent battle in which Sarnoff got the FCC to change the FM band spectrum location. This FM band frequency change ruined Armstrong financially as all the Scott FM receivers and his FM transmission equipment did not work on the new FM frequencies. The personal stress and financial loss was so great that it was a substantial factor in Armstrong committing suicide. His wife kept up the patent legal case and decades later won against RCA. Also eventually Armstrong got very deserved recognition from broadcast engineers for his many contributions to broadcasting. The change in FM bands hurt Scott financially in that a lot of their expensive equipment now had a useless FM band. I think that E. H. Scott changed hands and its name changed to Radio Craftsman and then later Ravenswood which eventually had a plant in my home town.

I clearly recall when young of an extraordinary broadcast I heard on one of these Scott Philharmonic radios. A station got hold of an English Decca FFRR full range 78 recording that had a disc frequency response out to 15KHz for a 78 record! This was played on a wideband AM station and I heard it on the Scott set. Superb sound, and a stunning experience I will
not forget. Later on, I got a newer E. H. Scott receiver made in 1947 which had the new FM Band, and also a very good AM section, but it was not as good as the older Scott Philharmonic. This 1947 radio is now 62 years old and still going strong. No problems or bad parts, other than a few tubes, in all these years. They do not make them like that anymore.

In the early 1950s stereo recording began and prerecorded tapes came to market. Later, about 1958, stereo records came out. Then broadcasts started to be updated. They started with simulcasts which would broadcast TV programs and then feed the local FM station the mono wideband audio for better sound quality while one watched the performance on TV.
Then stereo simulcasts started with one channel on an FM station and the other channel on AM. The FM was better, but the AM could still be excellent if the receiver was good and the AM station took out the signal processing. I set up my Scott for the AM and used something else for the FM. The AM quality and stereo sound was excellent. There were no crosstalk
problems or high frequency birdies. Then the effort to make FM itself into stereo. The technically better system was by Crosby, but the Crosby may have had mono compatibility issues, and they did not have influence with the FCC. Instead, the Zenith GE FM stereo system was chosen which had mono compatibility, but was technically inferior in stereo with more noise, a filtered bandwidth reduction from 20Khz to 15KHz, the 19Khz pilot tone birdie issue, SCA interference, etc. Zenith GE Stereo FM had influence with the FCC which decided the issue of broadcast standards at the time.

Before 4th grade I would build tube crystal radios with cat whiskers and also collected old radios, etc. By 4th grade I became a Ham and Stereo enthusiast. I made my own Ham radio, wound the coils, did all the metal work, hand wiring, etc, This project took two years to finish. I continued into the kit era. I do miss the fun of making things from kits, but Heath, etc are long gone.

AM died on the vine as far as music and sound quality was concerned. It took decades for AM stereo to be developed. By then, it was too little and too late. FM could be a lot better than it presently is, but this has been discussed before.

A few memories of older times for those who may not know.

Charlie Richardson



On Jan 6, 2009, at 10:20 PM, Steven C. Barr wrote:

----- Original Message ----- From: "Bob Olhsson" <olh@xxxxxxxxxxxxx>
-----Original Message-----
From Anthony Baldwin: "...the generous bandwidth of 
national AM channels in the 1930s and '40s offered a far higher level
of AM fidelity than we're used to today..."

Most younger people don't realize that the average AM station of the 1940s
sounded far better than the average FM station of the '80s.

And they had MUCH better AM radios as well! Consoles usually had 10" or
12" speakers. My E. H. Scott 800-B is admittedly MUCH better than average
(it cost $1600 in 1946...more than a new Chevrolet...!!) but puts out 25 watts
of power into a coaxial speaker with a 15" bass driver...!

...stevenc

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