Today, it's a trip to Working Lunch on BBC2, where I've been asked to reply to viewer's technical questions. These were sent over a couple of days before and powerfully reminded me of the days when I was "Dr Rupe" on Sinclair User -- a mixture of the sane, silly and utterly impossible. "My Spectrum no longer loads games, but shows a collection of flashing multicoloured squares when I turn it on. Is this normal?" "Yes, indeed, Mr Thrimble of Peckham. It means your Spectrum has fried itself for no apparent reason other than to irk you, which is perfectly normal."
We've moved on these days to a world of VoIP, spam, spyware ("Buy a Mac. But please, please, please don't keep going on about it") and Internet access from remote places. Yet somehow, I sensed, these were the same people who wrote to me twenty years ago.
One of the questions was "how can I watch TV on my computer, and what's the quality like?" (curiously consumery for a thoroughly business-oriented programme, but there we go). I said that it was easy, TV cards, USB, Hauppauge, digital options, blah -- and that the quality was splendid. "As good as you get in a TV studio", I said, grandly.
Oh boy. Wrong again.
As nobody in the studio could remember the combination number for the green room -- thus protecting the famous BBC coffee and custard Danish combo from all-comers, especially hungry contributors -- I and my laptop got dumped in the back of the gallery. This is where programmes are made, and consists of a dark room, one wall of which is lined with fifty monitors. Five hyperactive people sit there, ostensibly worrying about camera angles, sequencing clips and counting backwards but in reality passing their time by sending each other out for chocolate, crisps and gossip.
It was the wall of monitors that got my attention. We all get taught at school about the Doppler Effect and how it causes the cosmic red shift. The Curry's Effect is much more complicated. It's where you go shopping for a new telly only to see that each of the sets on display is showing a subtly different hue, picked randomly from the spectrum. Well, Studio 8 in the Television Centre could double as any provincial outlet of Dixon's Store Group. "Oooh, that's a bit magenta!" said the editor, pointing to one of the monitors. "Mine's yellow" said another. "Looks OK on that one", said a third.
So don't expect too much from the great analogue switch-off. We may have crisp, noise free widescreen broadcasts, but if they're made in Studio 8 the televisions of the nation will look like chameleons on mescaline.
I, for one, cannot wait.