[time-nuts] GPS Antenna Grounding/Lightning protection.

Dan Kemppainen dan at irtelemetrics.com
Mon Jun 18 14:29:38 EDT 2018


Hi,

I have (or had, I guess) a GPS antenna on a tower that took a lightning 
hit yesterday.

You can tell it's going to be a bad day when you walk into your shop, 
and smell burnt electronics. Still have to troubleshoot exactly what got 
hit, but the GPSDO was flashing no GPS signal, the 5V supply for the 
antenna to the GPS splitter was dead, the data logging computer had 
rebooted and the data logging computer monitor was dead. Other network 
hardware was dead also.

This is a bit surprising since the tower itself is grounded with 4 
ground rods and bonded to a 150 foot deep well casing near by. The 
antenna is on the end of 250 ft run of RG6. The GPS antenna cable shield 
has a grounding block bonded to two ground rods driven down below the 
basement foundation where it enters the house. I'm guessing the surge 
ran the coax into the splitter, then through everything connected to it, 
despite the grounding block.

So, I'm wondering if there are better surge protectors for lightning 
protection? Maybe something that actually protect the center conductor 
also? Hopefully something that will pass GPS signal reasonably and let 
DC power through. If so, can you recommend some starting points? Other 
suggestions also welcome.


Also, If you are considering upgrading your own lightning protection, 
hopefully this will be some inspiration to get started. As I said 
earlier, it's a bad day when you smell burnt electronics in the shop.

Thanks,
Dan




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