[CQ-Contest] How to fix CATV ground problems during T-storms

donovanf at starpower.net donovanf at starpower.net
Wed Jun 3 20:11:29 EDT 2020

Hi Dennis, 

I'm sorry to hear about the damage from your nearby lightning strike 

Your experience highlights the critical importance of bonding together 
and grounding all conductors entering your home. If there's an 
instantaneous voltage difference among them during a nearby lightning strike, 
bad things WILL happen. 


----- Original Message -----

From: dbmcalpine73 at gmail.com 
To: cq-contest at contesting.com 
Sent: Wednesday, June 3, 2020 8:54:44 PM 
Subject: [CQ-Contest] How to fix CATV ground problems during T-storms 

Last week, we had a T-storm with one lightning bolt hitting about 100 yards 
away. To my surprise, there seems to be very little damage from electricity 
surges coming through the AC mains. Instead, it seems to have traveled 
along using the CATV coaxial cable, perhaps on the cable shield. In our 
house, we lost two cable boxes (out of four installed and operational) ant 
the TVs associated with them. The TVs would actually turn on but there was 
no picture, indicating the damage was probably done to the TV's front end. 
The internet/CATV and phone service were out for several hours. I lost my 
ham PC, irrigation system controller, RS-232/USB adapter and I/O board for 
the K3 and a Winkeyer. No indication that anything came in through the AC 
mains. The same story was true for pretty much all of the 5-6 houses that 
were in the immediate area of the lightning strike, i.e. TVs and cable boxes 
were blown (but not all of them in a house) and a few other things but very 
little damage coming in through the AC mains. 

I think this indicates that the AC ground was pretty good for the houses in 
the area. On the other side, it would seem that the ground on the cable 
system leaves a lot to be desired. We can improve our AC ground, as many of 
us have done, but I don't think we can do much about the cable systems 
grounding. Anyone had experience with this situation and, if so, how did 
you get it fixed and protect yourself from future such events? 

Tnx, 73, 

Dennis, K2SX (temporarily QRT) 

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