(H.H.M.S. stands for His Hellenic Majesty's Ship.)
7. German sabotage at the Cable & Wireless station at Pallini, Greece, in World War II.
As the German army was pulling out of Greece in October 1944 its engineers carried out extensive sabotage to installations of a strategic value. At Pallini, not far from Athens, an attempt was made to destroy the transmitter hall by dropping one of the antenna towers onto it, but the equipment was not damaged.
They were more successful at the Royal Navy transmitting site at Votanikos. Here they tried to destroy six 300 foot tubular masts. One remained standing and also the lower part of another. All the test gear in the lab was thrown out of a second floor window and burnt. I was acting as official photographer for my unit at the time. When I walked into a small store room I saw all the equipment had been thrown off the shelves on to the floor, but appeared to be intact. I spotted a box of brand new packed German navy morse keys and decided the time had come for me to acquire a small war trophy of my own. As I bent down to pick up a key, I was horrified to see two large sticks of gelignite perched perilously on the edge of a shelf. The explosive was tied with white ribbon, with a weight attached to the other end. I froze to the spot. Gingerly I lifted my trophy out of the box and began to walk slowly backwards, being very careful not to knock anything over. I breathed a sigh of relief when I was out of the room and immediately alerted the engineers who came and defused the booby trap. So this book might never have been written thanks to the German army.
At the Athens broadcasting station transmitter site at Liosia my unit erected a small temporary 'T' antenna which allowed the station to come on the air again, but a short time later, when the ELAS guerrillas overran the area they began using the transmitter to broadcast their own view of events. We provided the broadcasting authority with a BC 610 mobile transmitter installed next to the Parliament building in the centre of town, using the same frequency of 610 KHz. Listeners in Cairo couldn't understand what was going on when one moment they heard an official government announcement and a little later a war communique issued by the Communist guerrillas.
8. Over-the-horizon or Ionospheric HF Radar—OTHR
As mentioned briefly in Chapter 1, it was in April 1976 that the then Soviet Union first unleashed a diabolical noise on the HF bands which caused widespread interference to all broadcasting and telecommunication services between 6 and 20 MHz. On the first day the "knock-knock-knock" went on continuously for over ten hours. Radio amateurs, who were among the services that suffered from the interference, soon came to call this noise "the woodpecker". By rotating their beams when tuned to the 14 MHz band they established that the transmissions appeared to originate from the vicinity of the town of Gomel in the U.S.S.R.
The governments of many countries world-wide immediately protested to Moscow, and all they got in reply was a brief statement that the U.S.S.R. was carrying out "an experiment".
The reason for the very strong on/off pulses was probably because, at first, the Russians were using existing radar antennas which permit the transmitting and receiving functions to share the same antenna. Modern OTHR installations have different transmitting and receiving sites, often located many miles apart.
From the early 1950s pulsed oblique ionosphere sounders had shown that the normal ionosphere is much more stable than had previously been thought to be. The physical reason for this is that the incredibly tenuous ionized gas which does the reflecting has a molasses-like viscosity. Of course, there are daily and seasonal changes, but over limited periods of half an hour or so, the F layer at a given location is actually quite well-behaved. It bounces back signals in a nearly constant direction and with nearly constant amplitude—just what is required for good radar performance.