On 11/7/2017 9:31 AM, Gmail - George wrote:
Any electronics at the top that is connected at the bottom can have that potential on the equipment case (a DC ground loop so to speak) of 100 volts. Most times it is much higher.
It is a serious mistake to view lightning as DC. While there MAY be a DC component, lightning is primarily an RF event. IEEE studies show that the energy in lightning is (very) broadly centered around 1 MHz. As far as lightning (and any other RF) is concerned, that tower is an antenna, and must be understood as an antenna.
It is also a serious mistake to think of our antennas as the only means by which lightning enters our homes. Lightning comes in on power wiring, telephone wiring, and CATV wiring. It also induces current on wiring within our homes.
It is VERY common for lightning currents induced on wired Ethernet cables, connected to equipment with shunt mode surge protectors (MOVs) to fry computers (especially their Ethernet circuitry) in the loop that includes their green wires back to the panel. This happens in homes and offices with no radio antennas at all.
All of this is why the most important element of lightning protection, BY FAR, is proper bonding of all equipment and grounds in a building. This is all covered in considerable detail in N0AX's new ARRL book on Grounding and Bonding for hams. It is of FAR greater value than all the surge protectors you could possibly buy. And you can get most of the same information for free from these slides.
http://k9yc.com/GroundingAndAudio.pdf 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to [email protected]
