[Premium-Rx] Lightning hitting your Premium RX

[Danny Higgins]

While working at Racal I got the job of testing a new receiver for 
susceptibility to lightning.  The set-up involved getting one of the 
smoothing capacitors from a 10kW valve transmitter (16 microfarads at 10 
kV), charging it up then using a large insulated rod to discharge the 
capacitor into the antenna socket.  Even though I knew it was going to 
happen, the bang always made me jump.  The first test took the receiver out 
right up to the audio stages, but eventually we managed to get it to 
survive.  The input protection circuit consisted of a spark gap, a fuse and 
a choke.  I know this was not a representative test, but the receiver was 
not expected to survive a direct hit, only survive the large voltages 
induced by a nearby strike.

Danny
G3XVR