[Aavso-sid-list] VLF/SID monitoring

[Jean-Pierre Godet]

   Hello Nick !

On Wed, 6 Aug 2008, Nick wrote:

>
> Wonder if I can ask what you use for lightning protection - I've always been 
> concerned about putting up the same sort of  thing for fear of a strike 
> killing everything ...
>

   I use a neon bulb between aerial and ground, a russian circuit they use 
there to protect telegraphic lines, but very similar to the NE-2 bulb 
available (?) in Europe. That is on the antenna side, and before a serial 
capacitor connected to the band pass filter. There is also a 1 megohm 
resistor connected in parallele with the neon bulb. This is to prevent the 
static charge to slowly build on the wire, and then unnecessary start a 
discharge through the neon bulb when the voltage is reaching the striking 
voltage (==> noise).
   On the other side of the bandpass filter, the side looking the receiver 
or sound card, there are two 1N84 diodes, one reversed in respect to the 
other.

   I'm working like that already four years, 24/24 hrs 7/7 days with no 
problem till now. yes I know it's no 100 per cent, but, anyway...

   Best regards !

   Jean-Pierre

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