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Tuesday 2 October 2012

More mad electromagnetic stuff


  I was reminded of this yesterday whilst cycling in the rain under....



  ....a set of high voltage power cables. It was really damp and the pylons were buzzing and crackling in quite a scary way.  I don't know about you, but I can always 'sense' the presence of HV cables, they do some weird magnetic stuff to your brain, I'm sure of it. A bit like old CRT tellies - I can 'hear' them too. And, while I'm on the subject, am I the only person who can see LED's flickering??
  Anyway, I had a pilot friend who was a telecoms engineer and mad into amateur radio and stuff. On an airfield one evening he showed me around the inside of his car - it was more like Jodrell bank with all the radio equipment inside.
  "Watch this!" he giggled, and produced a fluorescent strip light from the boot. He held it next to one of the antennas on the roof and keyed the mike. The bulb aquired a spooky flickering glow whenever he pressed the button. Even better was when he transmitted and spoke - the bulb developed weird sort of standing waves in sync with his voice. Bloody brilliant really.
  But he wasn't finished! A mile or two down the road was a set up those extra high voltage pylons, you know the 400,000 volt ones where the cables are hung in groups of four.  We drove down and walked under the lowest dip of the cables, strip light in hand. It getting quite dark by this point and as he held the tube in the air, it developed a dim, plasma-like glow. The electromagnetic field caused by the cables was able to excite the bulb into life.  I found this similar pic but I suspect it must have been shot on a long exposure as it wasn't quite THAT bright.  Makes you wonder about people living under cables who claim to being made ill, getting cancer etc. A lot of electromagnetic energy going on there.




  A while later, I found myself in the sticks in deepest, darkest Hungary with the same bloke, Alex. Now, he was a bit of a curry monster and was getting withdrawal symptoms by this point. His mate, a fellow radio amateur, was driving out to meet us in a few days time and Alex wanted to get an urgent message to him. Now, a normal person would have phoned him but that was not in the spirit of things. He'd bought his tiny handheld 2 metre transceiver with him but it was far too puny to reach the UK, so Alex rooted around the local hardware shop and acquired some coax and wire. After a few calculations and some scary tree climbing, he put together an antenna, pointed roughly in the direction of the UK. It was an 'inverted V', a standard lash-up by all accounts.



It was connected to the transmitter and off he went...
  "This is Golf Four xxxxx Portable....  Broadsword calling Danny Boy....  My hovercraft is full of eels..." etc etc
  Bugger me, after a while there was a scratchy reply in a broad Leicester accent.
  "Station calling, carrier wave only. No mod."
  After several tries, it was clear that the voice part wasn't working but Alex decided to use the 'squelchy' part of the transmission as a morse key. He began squeezing the PTT rhythmically. The voice at the other end received the greeting in morse and laughed.  All this was done on a measly 1/2 watt of power!
  Then, the serious stuff. Can you remember that bit on the '2010' film when Dave Bowman asks HAL to keep transmitting the message for as long as he possibly can and that it's the most important message he has ever transmitted?  It felt a bit like that.  To this day, that message is still beaming through space 20 light years away from earth. Wonder what the aliens will make of it?

  -...  .-.  ..  -.  --.  +  .--.  .-  -  .-  -.-  ...  +  -.-.  ..-  .-.  .-.  -.--  +  .--.  .-  ...  -  . 

  That was it playing in the background earlier.  You can hear it again here




  "Bring Pataks Curry Paste.... Bring Pataks Curry Paste.... "


  Oh, and yes, it worked! A big box full arrived in the back of a car three days later!




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