Wright's Aerials

Albert's Attic Gallery

One day in December 1981 Hilary told me that our video wouldn't work. I was surprised to find a very strong test card signal on top of the VCR's output channel. A year before we had expected it Channel 4, in test card form, had arrived! Over the next few weeks we had a string of calls to communal aerial systems. The problem in every case was cross-modulation. The new signal from Emley Moor was, for a time, stronger than the other three, and in the case of some badly adjusted systems it was the straw that broke the camel's back. At the time we were using a J-Beam 18 element as our standard UHF array, and we were finding that the C4 (ch41) signal was about 7dB above the BBC-2 (ch51) signal. For a while we used J-Beam log-periodics in strong signal areas, and these reduced the discrepancy to 3dB.

It's interesting to note that the introduction of Channel 4 caused far fewer problems than the later introduction of Channel 5. I think this was because the UK channel plan was always designed around a four-channel network, so the new transmissions slotted in quite naturally. There were a few VCR outputs to re-tune, mine included, but overall there was only a tiny fraction of the hassle caused later by Channel 5.

During the year of the test card one very dishonest contractor (if you're reading this George, I hope you're blushing) was fitting notch filters to every communal system he went near, to deliberately remove the Channel 4 signal. The plan was to wait until the actual programmes started, and then make a mint from 'Channel 4 conversions', by simply removing the notch filters! I'm pleased to say that he was shopped, but I won't say by whom. . .

We couldn't fail to be aware of the imminent launch as we went through the summer of 1982. A large parcel of leaflets arrived, then a few weeks later another, and then yet more. Although we conscientiously handed a leaflet to every man, woman, child, and dog, we eventually dumped thousands of them.

After Channel 4 opened in November 1982 we had to wait a year before transmissions started from Crosspool, Sheffield. Although Crosspool is classed as a relay it covers a very large population. At the time I was told that the transmitter originally built for Crosspool had been diverted to Wales, because politics had dictated that S4C should have good coverage from day one.

When Crosspool Channel 4 finally got on the air it used ch21, and we discovered that a lot of Group A aerials were absolutely useless on that channel. The 'contract' aerials pretty well all had reflectors that were actually shorter than the correct length for a ch21 dipole, so the polar response looked like a star-fish! Even the mighty Antiference was tripped up ever so slightly. The design of the TC18A had to be hastily tweaked to provide a more even response. At least they bothered - most of the cheapo makes have reflectors that are too short to this day!

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