OddThinking

Once upon a time there were four free-to-air TV stations in Australia, known as Channels 2, 7, 9 and 10 – presumably because they broadcast on VHF 2, VHF 7, VHF 9 and VHF 10.

My father, Joe, at that time, had a TV with a tuner with eight available channels or positions.

So, each station was allocated to a position.

Then came a VCR. It could transmit on VHF 0 or 1, and was relegated to the bottom position. A new free-to-air channel appeared (SBS on UHF 28) and it was put in position 5.

Now, the VCR itself needed to be tuned, and it had far more positions than the TV. It could be have been tuned with positions 2, 7, 9, 10 and 28. My father protested. “Keep it simple!” he argued. So it was tuned the same way as the TV.

Of course, occasionally I would forget and try to record Channel 2 by setting the VCR to position 2, and actually record Channel 7. I remember sitting down to watch a recorded show and finding I had accidentally “ripped” the Flying Doctors instead – repeatedly over the entire season.

Eventually, the old TV was replaced. Now both the VCR and the TV could handle – and display – multi-digit channels. Again, my father protested. “Keep it simple! I can remember the old system!”

And so his TV setup never moved away from the legacy channel numbering system, despite all the elements being replaced several times.

One day, I had reason to plug a borrowed VCR into the TV. I played with tuning, completed the task, hauled away the borrowed VCR and returned everything to how it was.

I was called back angrily to fix the TV – when Position 8 was selected, Channel 2 was shown, rather than the VCR!

I apologised, re-tuned the Position 8 to the VCR, and left again.

The next day, I was called back again – when Position 8 was selected, Channel 2 was shown, rather than the VCR!

Huh? I fixed that yesterday? I re-tuned it, and scratched my head, and watched it for a while. It worked fine.

This repeated several times with my family getting more and more annoyed at me.

Finally, I was able to see it in action: If the VCR was turned off, selecting Position 8 would show a blue screen indicating no signal. Then, after a delay, it would start showing snow and slowly re-tune itself it to Channel 2!

As long as the VCR was on – emitting a signal – the TV would be well behaved. Turn off the VCR, and the TV’s tuner would go a’wandering.

It was very strange behaviour. Of course, to my family, it was all clearly my fault. After all, it never did that before I played with the VCR.

It took me some time longer to realise the cause.

During my playing, I had flicked a switch that made the VCR transmit on VHF 1, rather than VHF 0. The Position 8 had also been re-tuned to pick up VHF 1, so there was no visible sign that I had done this.

However, the TV had some smarts. If it found it was receiving no signal, it would take it upon itself to look for a signal on a nearby frequency.

When the VCR was off, and the TV was tuned to VHF 0, it couldn’t find any nearby frequency, so it sat patiently waiting for the signal to return.

When the VCR was off, and the TV was tuned to VHF 1, it figured that VHF 2 is pretty close to VHF 1, and re-tuned itself to Channel 2.

Hey TV designers, nice and useful feature… NOT!