|Deutsche Welle - Trincomalee, Sri Lanka|
Wednesday, August 15, 2018
Animals and Insects ... in Radio
It was back in the early part of the year 1985 that our DX editor Adrian Peterson teamed up with the well-known shortwave radio personality Jonathan Marks from Radio Netherlands and his wife Marian for a five hour journey by car across the island of Sri Lanka from Colombo to Trincomalee. The purpose for this journey through the sometimes-dangerous insurgency areas was for a visit to what was the Deutsche Welle relay station which had been installed in what had previously been a Royal Navy wireless communication station.
Following our inspection of the shortwave and mediumwave equipment in that very modern international radio broadcasting station, our tour guide at Deutsche Welle took us out into the massive antenna field. He explained that there were occasions when a tribe of wild Asian Elephants had broken down the protective fence surrounding the antenna field and they then encroached onto the station property, sometimes causing damage to an aerial system.
Then too he added, from time to time, a troop of wild monkeys has come parading through the area, swinging from the structural wires of the huge curtain antenna systems, though thus far, they had caused very little damage, and neither had any of them become electrocuted.
We should add that SLBC, the Sri Lanka Broadcasting Corporation, now operates the Trincomalee radio station, and that this our DX program Wavescan is regularly heard on shortwave from one of their four powerful 250 kW transmitters.
Then too, VOH the Voice of Hope in Zambia Africa has experienced a similar problem with monkeys invading their station property. There are many wild monkeys that live in the trees surrounding the antenna field of their isolated shortwave station. Sometimes they get so bold that they come right down onto the ground surrounding the transmitter buildings looking for food.
A few months ago, the engineering staff discovered that the air temperature in the main transmitter building itself was getting dangerously high; and in addition, the industrial air conditioning unit was no longer working.
When they investigated, they found that much of the insulating material surrounding the ducts from the compressors outside the back of the building had been stripped bare by the monkeys; and in addition, some of the electrical wiring had been broken off also. When all had been repaired and replaced, they were careful to ensure that all of the outer surfaces were monkey-proofed.
Over in nearby India, Manosij Guha tells us in the 2002 edition of Larry Magne’s now defunct annual publication Passport to World Band Radio that a shortwave radio station in his country had a similar animal problem. Manosij tells us that All India Radio AIR established a shortwave relay station near the small town of Aligarh some 60 miles east of New Delhi in 1971.
Initially this station, on its estate of more than 800 acres, contained two shortwave transmitters at 250 kW each, together with 39 antenna systems and 15 miles of feeder lines. Manosij Guha stated that on several occasions nilgais, the large brown Indian antelope, have invaded the antenna farm and been electrocuted in the antenna field.
On two separate occasions in two widely separated countries, sheep have been the culprit in causing strange sounds in a radio transmission.
The now silent shortwave station operated by Radio Australia in Victoria was installed on a property of 600 acres located at 490 Verney Road in what is now North Shepparton. Although the property is located in what is described as sheep grazing country, currently the area is becoming somewhat built up with local housing.
At the height of its operational capacity, Radio Australia Shepparton contained seven shortwave transmitters; 4 @ 100 kW, 2 @ 50 kW, and 1 @ 10 kW. On the antenna farm were 15 steel towers standing 210 ft high supporting 24 curtain antennas, with an additional four rhombic antennas for use in emergency occasions.
In its earlier usage in the postwar years, the growth of high grass in the antenna field became a problem due to the likelihood of fires during the hot dry summer. So a flock of 850 sheep were obtained, Border Leicester cross with Merino, and they kept the grass down.
On one occasion way back, apparently there was a meter in the transmitter hall at Shepparton that gave a strange erratic reading. When the staff investigated outside, they discovered that one of the sheep was scratching an itch by rubbing itself against a feeder line pole.
Back towards the end of the year 1993, a similar event occurred in England. It was reported that a government communication radio station at Scarborough in Yorkshire, Northern England was emitting strange high frequency noises. An investigation revealed that sheep were rubbing against what they described as an aerial pole.
Back towards the end of the year 1993, Jonathan Marks (again!) in his DX program Media Network from Radio Netherlands shortwave told the story of how a school of shrimp put their station on the island of Bonaire in the Caribbean off the air. The concentration of shrimp in the water pond clogged the water intake for the cooling system and the station had to be closed until the fish were cleared from the cooling equipment. The abundance of shrimp in the wetlands and shoreland areas of Bonaire attracts the Pink Flamingo for which the island is quite famous.
The March 1999 issue of Contact, the monthly magazine from the World DX Club in England, tells us another interesting story. They state that the National Rivers Authority in Great Britain inserted a tiny radio transmitter into 450 salmon fish so that they could be tracked as they migrate up the River Hirnant in Wales.
At one stage, their mobile radio detector indicated that one of these fish had leaped out of the water and was moving across dry land. The authorities tracked the mobile salmon with their radio receiver to the home of a fisherman, who confessed that he had been fishing without a license.
And finally, one for the birds! This item happened back during the 1940s, and it is taken from a 1995 issue of the American radio journal, Radio World.
The incident that we refer to occurred at mediumwave station WBAA, which is still located at Purdue University in West Lafayette, Indiana. At the time, the station was located in the Electrical Engineering Building, and the antenna was suspended between two towers that were part of the steel framework of the building. These towers extended 88 feet above the top of the building and they supported a cage antenna made up of several parallel conductors each about seven inches apart.
One summer afternoon back in the 1940s at about four o’clock, the meter on the transmitter indicated a gradual change in the antenna current. The operator checked all systems, and everything seemed to be OK. After half an hour with very low antenna readings, the meter reading began to improve until it slowly returned back to normal.
Next day, and on the following days, always at about the same time, the antenna reading began to deteriorate to a dangerously low level, and then gradually return to normal. Now on Sundays, station WBAA was off the air, and on one occasion the operator happened to drive past the station at about the same time, four o’clock in the afternoon.
He was amazed to discover that the antenna was literally covered with Blackbirds, perched on the cross bars from one end of the antenna to the other. In spite of the heavy construction of the antenna, it was sagging noticeably, enough to change the level of capacitance with the ground.
In addition, the effective increase in the size of the antenna with all of the birds upon it changed the impedance factor of the antenna. This then was the cause for the low meter readings and the deterioration of the level of the transmitted signal.
Indeed, that cage antenna was actually … a bird cage antenna!
(AWR Wavescan/NWS 493)