Digger’s Diary – The geophysical survey 25th June 2010
25th June 2010 – A Town Unearthed
The Geophysical Earth Resistance Survey – East Cliff
Off to the East Cliff having not read the Health & Safety Leaflet for safety reasons of a psychological nature, not knowing a thing about any Geophysical Earth Resistance Survey and feeling a generally useless article.
Not so. The knitting I did years ago came in handy as all those wiry bits that were coming off a drum of cables started getting tangled up and had to be unravelled and I began to feel part of a team.
That drum by the way held the goods that did the JOB but we couldn’t get the cables off without a lot of smash ,bang, wallop from Vince and Bill our two very, quietly competent, leaders. Vince’s little invention fell to pieces and all he said was “I should have made that detachable”
Once we got all the cables together again we could see that it took the form of a square filled in with a grid of parallel lines marked at metre intervals. It was then pegged down into the ground but not just anywhere. Vince had set out where everything should go and I only realised much later in the day that he had marked out triangulation points all over the field.
Flags seemed to be very important and I am not sure I understood their significance but I dutifully put them where I was told and Vince came along later and sprayed the area around them with paint so that the points could be located at a later date if necessary. So that’s why!
That box on legs that you see in the Time Team programme is attached to a cable, attached to two probes located in the ground 15m away from the survey area and they don’t tell you this on TV but they talk to each other. They must have said an awful lot when I started to fold the cable in coils.
I haven’t told you this but the BOX has a personal minder who holds its cable clear as it plods along the ground with its operator (two minders no less). Coiling the cable to keep it tidy was not what was wanted as we progressed up and down the grid. COILING THE CABLE upsets the reading and I was asked very politely NOT TO DO IT AGAIN.
We took it in turns to plod. Straddle the cable one way, matching the metre points and plunge the legs of the box into the ground, BEEP. Get to the end BEEP BEEP. Turn round and back the other way down the middle matching the metre points again. Beginning to get the hang of this? Get to the end of the whole grid and BEEP BEEP BEEP.
Move the whole grid making sure it’s lined up to the flags (I think) and off you go again. That grid could be moved sideways as well as forward and how it all worked out is a miracle to me and a tribute to Vince’s invention.
The result of all this energy being expended over three days was that we got to see Folkestone’s “Underworld”. – In a matter of hours we all received a printout of what that box could see and we couldn’t, and, we think we have found a road or earth bank that no-one had any inkling was there. Is it a Roman road?
Only time and a lot of digging will tell. – Thanks Vince for being so patient with us.
Still can’t find my trowel