Lightning, not just the radio...

What use is an F-call? During the week we were subjected to some unusual lightning activity. There was lots to go around and it raises the issue on what to do when lightning is nearby. The obvious comments about disconnecting your radio from your antenna is pretty common knowledge, but there are other things that might happen that you hadn't thought about. Lightning is an electrostatic discharge, and strangely enough, RF is closely related, in that your antenna system converts electric energy into voltages that you then insert into your radio. So, lightning will just as easily affect your antenna as it does your radio. We have a basic understanding that a lightning strike directly into the radio is a good way to let out the magic smoke and a comment should be made that you don't need lightning for this to happen; just static electricity in the air is enough to build up enough charge for your radio to die. It's not uncommon to see sparks between the center and shield on an antenna connector while thunderstorms are about. While all this is going on, I'd also like to point out that the feed-line can be affected by lightning and it doesn't have to be a direct strike. Your coax may be heated up, a short might happen, a connector might be affected and if you have lightning arrestors, they might be fused. The point of this is that even if you disconnected your antenna from your radio to protect it, the rest of the system might be affected and it pays to check the state of your antennas and feed-lines before resuming the operation of your station. If you don't, you may find yourself in a situation where your radio survived the lightning storm, only to die when you put full power into your antenna system. Finally, lightning doesn't only have to come from above. If you are near a strike, the earth might come up and bite your hardware from the other end, it's called earth potential rise or EPR and it can kill. The killer isn't that there is a high potential, it's that there is a difference in potential. From the impact point of lightning, potential is dissipated in all directions. As the distance from the impact point increases, the potential decreases. Imagine a field where lightning strikes. Cows who are facing the lightning will have a different potential between their fore and rear legs, causing a current to flow through their bodies, including the heart. This is enough to kill. A cow standing side on has the same effect, but the distance is the width of the cow, not it's length, so the currents are less. This same phenomenon happens within your station. The earthing system, the radio, power supply and the like. So, lightning, it can ruin your day if it hits directly, but you should pay attention to it even if it didn't hit you. I'm Onno VK6FLAB