Dave Casler, KE0OG, discusses how to help protect your equipment from lightning. This video accompanies the Ask Dave column in the December 2022 issue of QST magazine. Join ARRL at www.arrl.org/join
I was a Field Engineer for AMTECH CORP. years ago now, we pioneered the RFID tags used in the automotive, Toll, railroad, aviation, intermodal container industries. For the Toll applications the RFID reader antennas were mounted on road light poles on average about 25 feet up,some higher, some lower, I was based in Oklahoma. Every storm season we would take strikes all the time. The one thing that rang true was you could count on every strike was different, some would take out antennas, others would knock out the RF transmitters and other times we would just get a surge and the systems would just start slowly decaying. We would eventually install the gas type arrestors, some would work, but in a direct strike you still would see failures. Rodney Whitfield KC5DZH.
Are lightning arresters and grounding the same thing? I mean if I use a lightning arrester and it's grounded to a rod I'm good to go. My antenna is grounded?
Hi Dave, you mentioned DC continuity in this video. Why would DC continuity be important or needed? I'm still very much leaning about this topic so I appreciate any help you can offer. 73, de KD7SJT
Lightning can me mega volts, not several thousand. The break down voltage is much more than a few volts. At leat I hope so since the voltage at 100W is already 70v into 50 ohms and over 300V at 2000W. If the SWR is higer than that then it can be many times that. On that just an arestor and a properly bonded ground rod alone wont do much. You need multiple electrodes. Yes recomend 100%. Technically shielded cables dont requre it under NEC it is a good Idea. For controll cables and open wire feeders its absolutely required under NEC. 810.21. The ground rod at coax entrance is also NEC requirement. Half or more hams ignore that. They are called surge protectors because they are just that. They wont arrest direct lighting strikes without a good well designed ground system done to NEC codes.
I was a Field Engineer for AMTECH CORP. years ago now, we pioneered the RFID tags used in the automotive, Toll, railroad, aviation, intermodal container industries. For the Toll applications the RFID reader antennas were mounted on road light poles on average about 25 feet up,some higher, some lower, I was based in Oklahoma. Every storm season we would take strikes all the time. The one thing that rang true was you could count on every strike was different, some would take out antennas, others would knock out the RF transmitters and other times we would just get a surge and the systems would just start slowly decaying. We would eventually install the gas type arrestors, some would work, but in a direct strike you still would see failures. Rodney Whitfield KC5DZH.
Are lightning arresters and grounding the same thing? I mean if I use a lightning arrester and it's grounded to a rod I'm good to go. My antenna is grounded?
Is there an advantage or disadvantage to installing the lightning arrestor at the antenna side of your coax? What about an arrestor at each end?
Do i need a Lightning arrester for a DB420 8 bay UHF folded dipole antenna
Hi Dave, you mentioned DC continuity in this video. Why would DC continuity be important or needed? I'm still very much leaning about this topic so I appreciate any help you can offer. 73, de KD7SJT
One example is an antenna splitter that's run by DC power fed up the coax.
Lightning can me mega volts, not several thousand.
The break down voltage is much more than a few volts. At leat I hope so since the voltage at 100W is already 70v into 50 ohms and over 300V at 2000W.
If the SWR is higer than that then it can be many times that.
On that just an arestor and a properly bonded ground rod alone wont do much. You need multiple electrodes.
Yes recomend 100%. Technically shielded cables dont requre it under NEC it is a good Idea. For controll cables and open wire feeders its absolutely required under NEC. 810.21.
The ground rod at coax entrance is also NEC requirement. Half or more hams ignore that.
They are called surge protectors because they are just that. They wont arrest direct lighting strikes without a good well designed ground system done to NEC codes.