Whereup> Plausable, just 'false to fact'.
Sullivan is correct.
As Sullivan acknowledged, some old TV sets did work like Bonomi's1930s Crosley: they required "tuning in on a single band by twiddling an analog variable tuning capacitor to the right frequency [which] would have been difficult."
But by the 1950s, TV set manufacturers were installing "turret tuners" to simplify VHF tuning. A single knob rotated a cylindrical mechanism fitted with twelve little hand-wired circuit boards, one for each channel. Each circuit board had a bunch of capacitors, some hand-wound coils, and a row of metal contacts that mated with metal springs. As each circuit board was brought into position by the rotating mechanism, the springs mated with the contacts on the board, placing that board in the circuit.
After the introduction of UHF, turret tuners were manufactured with 13 circuit boards, one for each VHF channel + one that switched to a separate UHF tuner. The UHF tuner was tuned in one continuous-tuning dial.
On each channel, the fine-tuning control engaged a tuning slug inside one of the little hand-wound coils.
Here's a link to a picture showing a turret VHF tuner (left) and what appears to be a continuous-tuning UHF tuner (right). This particular photo happens to be on a British website, but the basic structure of the turret mechanism is the same in the USA.
Things got even worse when we introduced our first pay service (HBO) in1978. We "hid" it in the midband on cable channel 17, "in the clear" (not scrambled, not trapped). We provided each HBO sub with a primitive converter: a little box with a single two-position switch:
- One position converted channel 17 to channel 2 for HBO.
- One position passed the incoming cable signal through unaltered for channels 2-13.
It wasn't very good security, but the powers-that-were considered it to be good enough, since turret tuners couldn't tune it.
Well, it wasn't long before local TV shops discovered a new line of business: retuning one of the lesser-used turret circuit boards (like public access) to channel 17.
Of course, Bonomi's old Crosley would have tuned to it. But by the1970s, virtually all TV sets used turret VHF tuners. Varactor tuners with digital displays were just coming on the market, and the old continuous-tuning models had just about disappeared.
A few years later, we moved HBO to channel 2 (so we could sell HBO to hotels and motels), installed negative traps to secure it, and abandoned all those old two-position-switch converters. But some people never figured it out: for years thereafter, those old boxes kept appearing at garage sales and flea markets, sometimes accompanied by "get HBO free" signs.
As for the folks who paid some TV shop to illicitly retune a circuit board to channel 17 ... well, they got what they paid for.