Aerial Photography - Modern

The local relay was less than half a mile away across the valley and clearly visible, but signals from it were rather low, and ghosting was a problem. We went to the relay site and found out why. The transmit aerials pointed up the valley and down the valley, but not across the valley. The strongest signals went down the valley to a variety of large buildings, from which they bounced back to cause ghosting at locations near to the transmitter. I guess that the BBC engineer responsible had tailored the transmissions to provide equal field strength at all points along the valley, but it hadn't occurred to him that areas just across from the transmitter would suffer from ghosting. The stacked TC18CDs more or less solved the problem. The aerial at the top is a Sunfen (Norwich) 18 element designed specifically for channels 35 to 39, used here for C5 on ch37. The narrow bandwidth gives very good gain and directivity.

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