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Cornish Hazards
© Chris Youlden, 2013


The first flakes of snow were already falling as I made my way back a second time to the lonely farmhouse on the moors above St Austell in Cornwall. Before I had chance to ring the big old-fashioned doorbell, the door sprang open and a middle-aged blonde woman greeted me with the words "Ah,come in! I was expecting you!"

It was January 1990, and I was planning a live OB for the Pebble Mill Daytime programme on BBC1 the following week. At that time the daytime strand had been running a series on home improvements, visiting houses where the owners were doing conversions, such as bedrooms in the loft etc. This one was about turning an attached garage into another room, and was in an advanced stage of completion.

I had received a phone call a few days before, as per normal, from the OB engineering manager inviting me to a planning meeting at the OB site where I would plan and arrange the vision and audio circuits required. The most usual way of providing this was via temporary microwave links, since satellite operations were still at an early phase. Some research was applied into the most efficient way to route the vision signal to Birmingham, using the BBC's internal contribution network where possible.


Computer plotting

We had taken delivery of a profile plotting program on an Atari computer produced by Research Department primarily for transmitter coverage. Viewed from today's computer standards it would seem archaic, but at that time it was revolutionary. Previous SHF planning required the use of mapping tables, with maps joined end to end. A pencil line would be drawn between one site and another, with heights along that line plotted on special graph paper. Earth curvature was taken into account. If nowhere did a high point pierce the pencil line, all was well as long as Fresnel clearance was also taken into account. Woe betide any planner who overlooked a thin ridge of hills along the path, as this could mean curtains for the OB. Often a radio link test had to be booked to prove the plot.

Then came the revolution. From the comfort of one's office swivel chair, a computer plot could be done. Enter the NGRs of two points and the profile plot would appear together with the earth's curvature and Fresnel curves. Modern versions of this are abundant now, but in those days we were in a privileged position to be allowed to use the program. There was a cautionary note on this, however. One had to check the result carefully, as there were known errors where it could miss some high points.

Then a new software update was released which added another extremely useful option. By entering an NGR and the height of the mast/aerial, then selecting an area to scan, one could generate a grid plot, where black represented a point which was obscured i.e. not line of sight, grey represented a point which was within the first Fresnel zone, and white was line of sight. Each point or square represented one kilometre square on the OS map. But one kilometre is quite a distance, and if it was white on the plot, then it meant that 'somewhere' in that square was a high point line of sight to the mast. So one had to be very careful.

I used this plotter to find some possible midpoints from the OB site at St Austell to BBC Plymouth where we could enter the BBC network. There were several that popped up, but only one had real potential, and that was located up on the moor north of the town.


Planning visit

We met at the OB site at 11am. It was a bitterly cold day with snow forecast. The planning process duly swung into operation and notes were made of the requirements. However, it was taking quite a while to agree all issues, and I was becoming nervous about the weather, since I needed to get up on the moors and snow was in the air. Finally, just before lunch I was able to make my excuses and break free from the production team to head for the hills.

Looking carefully at the OS map I found a track to a farmhouse which ran along the ridge of a hill in such a way that a midpoint van could park so as to see the OB site over a hedge and with a good aspect out towards Plymouth. An ideal site. The next thing to do was to obtain permission to park there and offer a wayleave payment. I rang the farmhouse doorbell. After a few moments the door swung open and a slightly dishevelled blonde woman enquired what I wanted. I explained and she asked me to come back after school ended that day.

This was of some annoyance since I wanted to get off the moor and head home - but there was no choice. So it was back down to St Austell for a tiddy oggy and slice of lardy cake whilst I drew the site plan for the midpoint.

On my return at 3.30pm I was invited in to the farmhouse kitchen by the smartened up blonde woman. Would I like a drink? I thought a coffee would be most welcome, but then noticed she had reached out for a bottle of whisky from the sideboard. Somewhat perturbed at this development, I turned the offer down on the grounds that I was about to drive a long distance in bad weather. We agreed on the wayleave payment and her name and address were recorded.

It was then that she explained her interest. She was an out of work actress because of the Camelford Water incident, where aluminium sulphide had been poured inadvertently into a reservoir in July 1988 resulting in serious consequences for any drinking the water. She was one of those badly affected and had been very ill for 18 months, one symptom being that her hair had turned green, and had been unable to work. She would do anything, she said clutching the whisky bottle, to get back into television. Could I introduce her to the producer of the programme? She would be most grateful. I decided that the weather was taking a turn for the worse, so gave her the producer's name, told her where the OB was, and left swiftly.


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