TV (Television), Radio Dials ("Don't touch that dial") and Vacuum Tubes

I subscribe to the daily Chicago Tribune and on October 3 the bag included a copy of the Sun-Times as an advertisement. So I had a chance to read the Garfield comic that had three frames. The first frame shows Garfield watching a flat-screen TV. The TV had the narration of DON'T TOUCH THAT DIAL. The second frame had Garfield thinking OKAY, I WON'T. The third frame had Garfield breaking the fourth wall and thinking AND WHAT'S A DIAL?

I have already discussed a dial phone. Garfield's comic reminded me that a tuning dial is history for both radios and TVs.

TV Tuning Dial

My first TVs, including my first color TV --- a 19-in RCA XL100 --- had dials for selecting the channel.

Photo by Bmuscotty88, CC BY-SA

I had to hunt on the web for a while to find a photo of a TV that was old enough to have a dial and with enough resolution that you could see the numbers on the dial.

Digitally zoomed

When I was a kid, our TVs had just the top dial without the U. That is, the TV could receive just the VHF (Very High Frequency) channles 2-13. To change channels, you had to get up off your seat, walk across the room to the TV, and turn the dial to the new number. When you turned the dial, it would "click" (actually, "clunk" is probably more accurate) at each number. And you had to turn it rather strongly to get it to move to the next number. When I took the cover off a TV, I noticed that what is on the backside of that dial was rather complicated. It was several inches deep consisting of several banks of selector switches. It always blew my mind trying to figure out how they were manufactured in the factory. The newer model shown in the photo supports UHF (Ultra High Frequency) channels as well. If my memory is accurate, that dial turned smoothly.

The fact that we did not have a remote and we could not channel surf was not an issue because we had only three channels --- ABC, CBS, and NBC. Since there was just one TV in the house and just three channels to choose from, who was going to watch what was planned out long before the TV was turned on.

Why just three networks for so many decades? Sending video signals across the country was difficult. Fortunately, using underground coax cables across the country was invented about the time that TV was invented. One was laid across my grandfather's farm in northeast Indiana.

• 1936 — AT&T installs experimental coaxial telephone and television cable between New York and Philadelphia, with automatic booster stations every ten miles. Completed in December, it can transmit 240 telephone calls simultaneously.
• 1941 — First commercial use in USA by AT&T, between Minneapolis, Minnesota and Stevens Point, Wisconsin. L1 system with capacity of one TV channel or 480 telephone circuits.
• 1949 — On January 11, eight stations on the US East Coast and seven Midwestern stations are linked via a long-distance coaxial cable.

[Wikipedia]

Microwaves and satellites had to be invented to afford enough channels to make channel surfing a meaningful activity. Then when we were forced to switch to digitial channels, channel surfing became a joke because it took so long for each channel to buffer up and display an image. I notice now that they at least quickly display the name of the channel. With the advent of fiber optic transmission making streaming possible, channel surfing became even more silly. In fact, some would argue that the TV is obsolete.

I had read that the mechanical turner was the weak spot in the XL100 TVs. But that turned out to be OK because soon after I bought my color TV, I bought my first VCR --- a JVC for $800. (The last VCR I bought new was also a JVC, but it cost $30.) So the turner on the TV set on channel 3 because I used the remote of the VCR for channel selection. (Every once and a while I would click it back and forth a few channels to wipe any corrosion of the contacts.) I finally threw that 19" color TV away after a couple of decades, not because it quit working, but because I wanted a bigger TV.

Radio Tuning Dial

Radios had a knob that turned the shaft of a variable capacitor. There would be a cord that wrapped around the shaft of the little tuning knob and then the cord went around a big pulley on the variable capacity. It would take many turns of the knob to go from one end of the dial to the other. And you had to remember the numbers of the AM stations that you liked. (There was no FM radio when I was a kid.) To this day, I remember from the 1960s that WOWO (Fort Wayne, IN) was 1190 and WLS (Chicago) was 890. I no longer remember the frequency for WCFL, the other top-hits radio station.

Pinterest

I don't know what the lower scale in the photo was. When I was looking at pictures of older radios, I noticed that most of them had both scales.

Lois Tobias-Ushkow posted

Michael Kopcha

Looks like a Zenith Long Distance AM/FM Tube Radio, 1950’s

Lois Tobias-Ushkow shared

Kim Andrus
Metz Portable 45 Record Player and AM Radio... " Beach Party Anyone!"?
Steve Dichter: 1956 Metz. German manufacturer.
[I wonder if that used a bunch of D-cell batteries. They would not have been rechargeable back in the 1950s.]

Photo

A variable capacitor has two banks of metal plates. The lower bank was fastened to the frame and was stationary. The other bank of plates was attached to the shaft. In this case, when you turned the shaft clockwise, you would rotate the plates out of the stator plates, which decreased the adjacent surface area and decreased the capacitance. Likewise, turning the shaft counterclockwise put more area of the rotor plates next to the stator plates and increased the capacitance.

By the time radios were being installed in cars, the dial had been replaced by a slider.

Nathan Gryszowka

For a slider, the cord between the knob and the capacitor pulley was run across the top of the scale and the needle was attached to the cord.

Vanished Chicagoland posted
Today [Aug 20, 2021] is National Radio Day! Here is a 1960s Zenith Radio.

Robert Moynihan commented
Picks up all kinds of things like the atomic clock on one of the stations. A long thin wire antenna which I string about the room.

Glenn Kadas commented
Zenith wood cabinet. Still works. Takes a while for the tubes to warm up.

Photo from CollectorNet

The first purchase I made with my own money (lawn mowing and babysitting) was a portable transistor radio. I added a blue rectangle on the photo to highlight the "teeth" that stuck out on the side of the radio. These were on the tuning dial. This dial was directly attached to the variable capacitor shaft. There was no cord to "gear down" the number of turns between the knob and the capacitor shaft. It required careful thumb movement to tune in a station.

Update: A Flickr photo of a 1946 Farnsworth vacuum tube radio with a slide dial. 

More Old Electronics

This is a multiple waveband (shortwave, airplanes, police, amateurs, AM) show "Selector" displays only the waveband in use. (Note that wave band was still two words back then.)

Mike Matalis shared
Dennis DeBruler: It just occurred to me that we have generations of people now that have never experienced tuning a radio to the exact frequency because digital tuners do that for us.
[The Magic Eye gives visual feedback of how off-center the tuning is.]

Of course, back then it would be just AM, there is no FM scale. (Note the "Vintage Tech" album.)

Marie Dawson shared

Bob Garrett commented on Marie's share

If I remember correctly, after they played the anthem, they showed a test pattern for a while before they turned off the signal and the set would show static. You would also get static if you set the dial to a channel that was not used. I'm sure they also showed a test pattern before their first show so that you would know you were tuned in to an active channel. But I don't remember that because I was never up that early.

Keep in mind that $468 in the 1960s would be over $5000 today. If I remember correctly, I paid over $800 for my first VCR, and VHS unit. And I paid $30 for the last one I bought. And then you could not buy them new anymore.

George O'Brien posted

 

Michael Matalis shared
[Note the radio dial on the right side of the console.]

Comments on a post

Mike Breski shared
Shopping for a color television in 1965.
Don Kullas: Purchasing a color TV in 65 would cost around $4000 today. It was a major purchase back then.

Did this have "push button" tuning? If so, I wonder how they did it. When did WGN start? That might explain why they had a fourth button in addition to the buttons for NBS, CBS and ABC.

Jimmy Becker posted

I can't figure out how these "briefcase sized" TVs fit the rear of the CRT picture tube into the case. The dials are on the side.

Sean Brady posted
Admiral TV ad - 1965
Alan Carver: That's $905.55..in today's inflation.
Chuck Luciano: adjusted for inflation, that's over $1000. Today $1000 will buy a 75" TV.
[A comment indicates that these TVs were rather light because they were made with transistors instead of tubes. Transistors would help with the battery life as well. Other comments indicate these were made in Chicago.]

The dials are on the top.

Sean Brady posted
1959 - PHILCO
Bob Straub: According to the U.S. Bureau of Labor Statistics CPI Inflation Calculator, $159.95 in August of 1959 had the same buying power as $1,681.81 in August of 2023. Inflation is a sneaky tax.
John Lauter: 62 lb. “portable” because it has a handle on the top!

Sean Brady posted
12/2/1949-Sunbury, PA: These television chassis, show moving down the production lane at the Westinghouse Electric Corporation's plant in Sunbury, are the product os some 1,450 seperate operations. At the end of the war there were only 10,000 television sets in operation in this country. Growing in audience appeal, 185,000 sets were built in 1947; 950,000 sets were built in 1948 and thi year's production, by all manufacturers will be in excess of 2 million sets.
Tim Makins: Circular screens? Then how was a rectangular picture shown? Did the screen show a circular portion of the image, or was part of the screen unused?
Phil Nasadowski: Tim Makins Part of the screen was masked off, usually. Some companies did a round screen. Remember, TV was new, and folks didn’t know what a TV should look like.
David Fleegle: Tim Makins It was a little of both. The screen had a bezel in front that blocked off some of the picture tube.
Greg Carey: David Fleegle The orthicon pickup tubes in the cameras were also round. The electronic scanning however represented a 3x4 rectangle in the center which was reproduced on the round picture tube (CRT). The ability to make glass envelopes with squarish corners to reduce the unused parts of the CRT came years later.
[Note the 1965 Color TVs in Mike Breski's post above had round CRTs but the B&W tubes in the background were rectangular.]
Keith Chrysler: The Germans were 20 years ahead of us in tv. They were doing "patriotic' broadcasts in the early 30s with great clarity.
Patrick Kirtley: To me the amazing thing is that these units, being carefully designed and manufactured, were intended to last decades. But even then, technology was rapidly changing and the cycle of quick obsolescence had begun.
Bud Bennett: It boggles the mind that all those chassis were hand wired by individuals doing point-to-point soldering. Hundreds of components per Television set to make them work. PCB's (Printed Circuit Boards) wouldn't become a thing until the late 50's.

Comments on Sean's post

David Myers commented on Sean's post
I recently restored a 1949 Motorola TV, and thought the CRT was a dud as it gave a very dim image. Turned out the ion trap magnet had gone weak with age. It had a round CRT that was masked top and bottom, as was popular at the time. By the early 1950s, rectangular CRTs began to appear, and over the years, as technology improved, the corners became progressively squarer.

Alan Lehman commented on Sean's post
Early sets did have round displays. By the early 60's, squared corners were the norm.

Harry Moore posted three photos with the comment: "The world's largest television October 1973 (TV) tube at its time, a 226-pound, 36-inch cathode ray tube (CRT), intended to be used to train Air Force pilots. Developed by the Air Force Human Resources Laboratory at Wright-Patterson Air Force Base, the CRT was to be used in the advanced flight simulator. The tests were underway at Williams AFB, Arizona. Other tried in 1937"

Ned Carlson: DuMont made a 30 incher in 1950. I saw one, and the owner had it rescreened and rebuilt. Rebuilding CRT's with new guns used to be a thing and was a big business at one time.

The old flight simulators used some kind of projector with a 4-65 Eimac as a sweep tube. Not sure how that worked. Hopefully it was better than the driving simulators I used back in the 70's 😉

Philip Crosby: In the late 80s, Sony built a 46" Trinitron CRT for their HDTV monitors. The monitors had threaded sockets, 3 on each side, for rods that a team of six persons could use to transport it.

Kinda like coffin bearers.

Andrew Wilson: Philip Crosby I remember selling Sony's first 27" Trinitron TV. It was the largest CRT TV we sold ever. I eventually bought one for myself. We thought it was huge! That thing weighed a ton. A two-man job to move it safely.

David Breneman: The RCA tube was called a “demountable” Kinescope. The bell was steel and the glass screen clamped to its face. As you might guess, the seal was not 100% leakproof, and there was a vacuum pump in the base that continuously evacuated it while it was running.

James Snyder: The largest CRT TV I ever used was a 60” Sony tube used at the Advanced Television Test Center during Grand Alliance testing in 1995. It took 6 men to lift the thing. I sat in front of that beast for months QCing the decoded video coming out of the proponent encoder/decoder.

[Several comments wondered about the quantity of harmful radiation that these big tubes would generate.]

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Ned Carlson commented on Harry's post
Oh, here's the 1950 DuMont 30 inch "Royal Sovereign" TV.

A vacuum tube tester.

Clarke Walker posted

Variations of these used to be found almost everywhere( and needed to be).

Remember to check the new tube before taking it home too.

Jay Krajcovic shared

Dennis DeBruler: When a family TV or radio quit working, I remember pulling out all of the vacuum tubes (except for the CRT, of course) and taking them to the local drug store to use one of these testers. When I found the bad one, I'd buy the replacement. It never occurred to me to test the new one. They always worked for me. I don't remember how I kept track of where to plug the tubes back in. If you look on the right side of the chart near the top of the tester, you see a knob. You would turn that to scroll the chart to find the model number of the tube you were testing. That would then tell you which socket to plug the tube in and what settings to dial in for the controls.

Jason Bailey posted
Spotted at the local guitar shop.

Jeffry Brooks: For testing the tubes in guitar amps?

Travis Parker: Jeffry Brooks yep. One of the applications where distortion from diving tubes out of spec is useful. You can do the same thing with DSP but tubes are a cheap and easy way to get that sound, assuming the tubes aren’t overpriced now.

Now, putting that same fuzz in reproduction amps vs instrument amps is questionable at best.

Short Stories posted