William_H
Well-Known Member
Re: SSB Radio: Backstay Insulators - what\'s the deal?
Hello John (morris Major) My experience of RF burns came from my youth as a trainee radio rech based at a local (national) radio transmitter. The aerial radiated 55 kilowatts on 690 Khz and 10 Killowatts on 720 kilohertz. The aerial was located quite some distance from the transmitter hall and so for trend monitoring purposes the meters in the antenna tuning hut were recorded every morning.
The obvious way to get to the tuning hut was by bicycle and the obvious ones to do the job were the young trainees. When you got there the obvious place to park the bike was leaning against the hut wall.
There was so much field around the aerial base that any light contact with the bicycle handle bars produced an RF burn. Hence the comment about grasping firmly. In fact you could sneak up to a coleague and lightly touch the back of his neck to draw a tiny arc which stung the victim while not being too bad on the index finger.
The aerial riggers said how they would turn off the power then ascend the aerial (about 500 ft.) It was normal to return the power to the aerial once they were on the aerial but they had to always ensure a firm grasp of the iron ladder to avoid RF burns. And jump off the bottom rung when finishing. (acttually in hindsight I wonder if that was true. over 40 years ago)
No I never got near to a real RF burn everything was safely protected by interlocks. They did transmit on 6 and 9 mhz but only at 10Kw for a local program to remote north of West Oz. The antenna switching with freq. change gave a lot of trouble with melted contacts but I had no experience there of burns. Sadly HF has all gone now.
I am sure that burns from RF vary a huge amount with frequency.
The bottom line is it is just as nice to avoid them. good luck olewill
PS sorry about the old reminissing.
Hello John (morris Major) My experience of RF burns came from my youth as a trainee radio rech based at a local (national) radio transmitter. The aerial radiated 55 kilowatts on 690 Khz and 10 Killowatts on 720 kilohertz. The aerial was located quite some distance from the transmitter hall and so for trend monitoring purposes the meters in the antenna tuning hut were recorded every morning.
The obvious way to get to the tuning hut was by bicycle and the obvious ones to do the job were the young trainees. When you got there the obvious place to park the bike was leaning against the hut wall.
There was so much field around the aerial base that any light contact with the bicycle handle bars produced an RF burn. Hence the comment about grasping firmly. In fact you could sneak up to a coleague and lightly touch the back of his neck to draw a tiny arc which stung the victim while not being too bad on the index finger.
The aerial riggers said how they would turn off the power then ascend the aerial (about 500 ft.) It was normal to return the power to the aerial once they were on the aerial but they had to always ensure a firm grasp of the iron ladder to avoid RF burns. And jump off the bottom rung when finishing. (acttually in hindsight I wonder if that was true. over 40 years ago)
No I never got near to a real RF burn everything was safely protected by interlocks. They did transmit on 6 and 9 mhz but only at 10Kw for a local program to remote north of West Oz. The antenna switching with freq. change gave a lot of trouble with melted contacts but I had no experience there of burns. Sadly HF has all gone now.
I am sure that burns from RF vary a huge amount with frequency.
The bottom line is it is just as nice to avoid them. good luck olewill
PS sorry about the old reminissing.
