Lightning enters the NØHR ham shack
Tower survives high winds
One hot & muggy summer afternoon, I was driving home when a major storm hit central Iowa. My daughter’s school, a mere mile away from my house, recorded 80+ MPH winds before the weather station was blown off of the roof!
The good news is that my tower and antennas did not take any damage as a result of these strong winds. Straight line winds blew cars off of Interstate 35 and snapped massive trees like twigs.
Lightning strikes twice
The bad news was the lightning. My next door neighbor said that my tower was struck twice during the storm. It’s hard to know if these were both direct hits. The first strike was apparently a massive hit that shook the walls/floors of nearby homes. He said that two houses on our street lost their wireless Internet transceivers. One neighbor reported that his battery operated Christmas ornaments started playing music in the attic.
Assessing lightning damage
I am still assessing the damage due to these hits. My HF transceiver (Icom IC-746) was thankfully not plugged into the coax runs from the tower. However, I did have an outlet strip that was plugged into the wall in the shack (ouch) - it was feeding my:
- Prosistel PST61D rotator controller
- SteppIR 4 Element yagi controller
- Samlex 1223 power supply (connected to the Icom)
All three of these were toast, as was the IC-746 and an old TV on the same circuit. Arraysolutions‘ rotator repair guy was quick to review the controller… the main circuit board needed to be completely replaced. SteppIR was also very quick to assess the damage to the controller…. a total loss. The IC-746 was shipped to Willco Electronics. No word yet on the damage there.
I have not yet assessed damage on the tower. Equipment prone to lightning damage would be the Cushcraft XM-240 (balun?), SteppIR 4 element motors (doubtful), rotor internals (MOVs?) and the protection gear itself installed at the base of the tower.
I did find a PL-259 coax connector (for the XM-240) that had black char marks on the shield and the center pin. My theory is that the lightning struck either the ANWireless tower itself or the XM-240 40 meter yagi and induced a surge onto an AC line that runs to the tower in the coax trench.
Reviewing and Improving the Lightning Protection System
Along with the still unknown amount of repairs, replacements and insurance headaches, I’ll be spending time trying to make the system a bit more bullet-proof. Immediate changes include:
- AC surge protection in the shack (already ordered through Amazon)
- Additional ground rods (currently have 5, 8 ft ground rods - will probably add another 5)
- Better grounding and a new layout of the surge suppression gear enclosure at the tower base. I wonder if the tight enclosure could have been an issue (arc?)
- Review what happened in the I.C.E. lightning suppression boxes (components blown?, bypassed?, ???)
- Consider a SPG panel at the house - entry point.
- Always disconnect everything when not in use. Period.
Looking at the picture of the I.C.E. lightning suppression boxes. The ground lugs don’t appear to be grounded?
Pat, I’m sorry to hear about the lightning strike on your tower! Hopefully, you will be back up and running again before long.
Take care and 73
Ouch!
I guess I got off lucky. The hit we had in 2002 wasn’t direct, but on a nearby utility pole. Still killed the rig and computer, and a couple of CATV boxes.
I found a couple of cables that had blown spots at regular intervals, one a coax run and the other a control cable. Both were parallel to the CATV line, which the path I think the hit came in on. My neighbors also had CATV connections damaged.
If you have not already, you might want to check your cable runs for shorts/opens on the conductors. For the coax, maybe a wattmeter and dummy load out at the tower. If the coax is suddenly more lossy than expected from its length, you could have another hard-to-see(and fix) victim.
Good luck de w4kaz