How's The Weather There ?


Aug 26, 2005
To my knowledge, lightening does not generate EMP, nuclear blasts do, possibly some other processes. Good thing it doesn't or electrical/electronic systems would be regularly wiped out over large areas. Risetime of real EMP is way faster than lightening, that's what gets you.
There's quite a bit of EMP in lightning. Worse, it inductively couples with anything metal. I've actually lost far more equipment this way over the years than voltage surges.

The only true surge-related damage I ever had to deal with was at a government transmitter site. Direct lightning strike to the tower. When the power came back on, we were offline and all sorts of alarms were going off. Upon pulling in the parking lot we found part of the actual antenna element laying in the parking lot, partially melted. Lighting had hit the antenna, went straight down through the Heliax hard coax cable and continued straight down, blowing a hole through the bend in the Heliax where it went into the transmitter doghouse. We could smell the doghouse before we opened the door. Every single surge protector had physically exploded, leaving poop stains all over the walls and racks. It didn't matter which brand, all of them there exploded. MUCH more damage inside the main facility which the doghouse was attached to.

Me being my typical a-hole self, wanted to see if the transmitters still worked. I did some quick wiring and hooked up the dummy load, and sure enough, all 4 of them still worked fine! We were floored. So, we spent the rest of the afternoon and evening at agency's vehicle maintenance shop fashioning a new antenna, running temporary coax up the tower, and cleaning up the mess. As part of the rebuild, I checked the complex's grounding system and found that it had multiple grounds all around the building. Each addition to the building had its own electrical system with ground, but was tied in with the existing parts of the building. Remember ground loops in audio? It's actually an electrical thing, and it seems many electricians don't understand it. We electrically isolated the transmitter/tower/antenna from the rest of the building and never had any surge issues ever since, and it's been ~25 years.
I'm sure that your equipment was hit by the EMP. We lost some equipment at work a couple of summers ago when a structure got hit a couple of blocks away. Our equipment was connected to long lengths of communications cabling which acted as an antenna for the EMP.
Long lengths of unshielded wire will definitely inductively couple with lightning. Down here, POE (Power over Ethernet) switches will blow individual ports often because of it. Regular network switches will as well, but the POE ones seem to do it at a much higher rate. I'm guessing the surge protection threshold has to be higher because of the 48vDC on the line. We still run ancient gear here, so the 48vDC to each port is switched by relays. I'm assuming newer network switches probably use solid state conductors for this and would be even more susceptible. HP seems the most resilient to this. Ciscos can handle higher temperatures than most, but blows ports regularly. I have some new TP-Link POE switches deployed, but haven't been through enough lightning storms to have an opinion on them yet.

Just curious: is this also true in the case of the structure where this damage occurred?
The electrical system at my temporary place is...okay... It was redone in 2012 when they ripped out the all-aluminum wiring. Typical residential stuff. Probably slightly better than average. No damage to anything else in the house, just the cable modem and an SDR USB stick. Both still powered up, but were deaf. The SDR radio's connected to a small ~14" antenna sitting inside. I have plenty of Internet of Crap devices all over the place too.


Flashlight Enthusiast
Nov 6, 2005
Treasure Valley, Idaho
After this afternoon's rain.