This is the fifth in a series of articles about my recent quest to replace a broken VCR in this era of DVDs, DVRs, and other newfangled gadgets. Click here for the beginning of the series.
Before we go exploring the mystery of the disappearing tuners in VCRs let’s take a look back at how cable ready tuners came into being and why they were such an important development.
TV signals are just radio waves that travel through the air like regular radio. Such signals are often called RF signals (radio frequency). In television, the RF signals not only contain audio information, they also contain video information as well. The tuner on a television set could be a smooth turning dial with frequency numbers on it just like a radio receiver. However to simplify things they picked specific frequencies and assigned them channel numbers. Originally only numbers 2-13 were defined. These are known as VHF frequencies (very high frequencies). It wasn’t until 1952 that the FCC designated additional channels 14-83 called UHF (ultra high frequency) channels. In the early 1980s channels 70-83 were reassigned to wireless phones. Click here for a Wikipdeia article about UHF broadcasting.
Early televisions had only VHF tuners which were a clunky dial that snapped into place from one channel to the next. Because this mechanical dial didn’t always hit the frequency exactly, you usually had another dial that you could turn back and forth smoothly that was called “fine-tuning”. It would adjust the frequency of the RF receiver in your TV set. In order to get UHF channels, typically would turn your VHF dial to a position “U” and then turned a smooth turning UHF dial to tune a UHF channel. Some UHF dials actually had fixed positions for each channel that would click into place but most simply had a smooth turning dial like a radio dial.
In 1962 the federal government mandated that all new television sets have a UHF tuner by 1964. The argument was that it was unfair to license a television station to broadcasts on a frequency that no one was able to receive. There are those that argue that this saved UHF stations but there are others who argue that initially cost consumers millions of dollars for TV tuners but most of them did not really need. When I was growing up we only had four channels here in Indianapolis. Channel 13 was the ABC affiliate. Channel 8 was the local CBS channel. Channel 6 broadcast NBC and Channel 4 was an independent channel from Bloomington. (No that is not a typo… at one point Channel 13 and 6 swapped affiliations to the current state of affairs where 13 is NBC and 6 is ABC). Eventually a local PBS station began broadcasting on UHF Channel 20. It’s much more recently that religious broadcasting began using Channel 40 and a local Fox network affiliate was established on Channel 59.
As I explained in a previous post, my first VCR had about a dozen individual tiny tuner dials that you would tune to specific channels using a small thumbwheel. There was also a small three position toggle switch to select lower VHF, higher VHF, or UHF channel ranges. If you drew a frequency graph and plotted the channel numbers on it you would see there is a large gap of frequencies between VHF channels 6 and 7. That is why the VHF channels were split into low and high ranges.
Eventually mechanical tuners and dial tuners were replaced by more modern electronic tuners that were much more compatible with remote controls. Early remote control TVs actually had a motor which turned the TV dial for you. Electronic tuners had no moving parts and were able to select frequencies precisely so a fine-tuning dial wasn’t necessary. For this brief era, everything was just fine. That is until cable TV came along and missed everything up!
In our next installment, we will discuss the chaos that came with the introduction of cable TV.