[Elecraft] Avoiding costly lightning damage to your radios gear
Walter Underwood
wunder at wunderwood.org
Tue Oct 30 16:47:51 EDT 2018
Spark plugs fire at 12,000 to 25,000 Volts. Some require as much as 45,000 V. I’d recommend something in addition to spark plugs. Gas discharge tubes have a turn-on voltage of 150 V to 2000 V, depending on the model.
wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)
> On Oct 30, 2018, at 1:29 PM, Mel Farrer via Elecraft <elecraft at mailman.qth.net> wrote:
>
> All this is good info. Some right on and some just there. From decades of using wire antennas with 600 ohm ladder line to a switch yard for selection, I use the old FORD approach. All ladder lines have back to back old Ford spark plugs in front of all the switching. The common point on the two plugs goes to the tower ground network. So even when the antenna is not selected the FORD's do their thing. No failures to date except the the pole Pig on the service pole to the house, it took a direct hit and blew a hole in the side of it. Needless to say we were then on Generator back for a while. Forgot to say the spark plugs have 5 w 1 Meg resistor across them to ground.........
> Mel, K6KBE
>
> From: Fred Jensen <k6dgw at foothill.net>
> To: elecraft at mailman.qth.net
> Sent: Tuesday, October 30, 2018 12:58 PM
> Subject: Re: [Elecraft] Avoiding costly lightning damage to your radios gear
>
> Does my K3 have a static bleed across the antenna terminal(s)? A number
> of years ago, our CQP team in Alpine County fried the front end of an
> IC-760 II in a snow storm [precip static]. Then, with an accumulated
> 300 or so years of amateur radio experience on the team, we replaced it
> with a spare ... and fried that one too. [:-) I have a coax Tee with a
> 100K resistor in a PL259 on my K3, just wondering if it's necessary.
>
> 73,
>
> Fred ["Skip"] K6DGW
> Sparks NV DM09dn
> Washoe County
>
> On 10/29/2018 8:08 PM, Wayne Burdick wrote:
>> Every year, especially in summer, our techs see radios come in that have been damaged by lightning, despite the radio's protective circuitry. You can take steps to reduce your own risk.
>>
>> 1. Many of us remember to disconnect antennas when lightning is anticipated. But in our experience, the most common source of damage, by far, is from an attached computer. Computers themselves often fail due to lightning strikes. They can also act as conduits for surges to other gear. Just to emphasize this point: Customers often say "I disconnected everything but the USB cable to the computer...," which left the interface to their radio exposed.
>>
>> Note: Only in rare cases have we seen surge damage via other I/O ports (accessory jack, paddle/keyer jacks, PTT IN, KEY OUT, and DC). USB and RS232 ports are the most susceptible.
>>
>> 2. Some stations have an ad-hoc ground system and little or no ESD or surge protection. If you haven't already taken protective measures, we strongly recommend reading this article, which goes into some detail regarding how lightning finds its way in:
>>
>> http://www.arrl.org/files/file/QST/This%20Month%20in%20QST/June2017/Chusid-Morgan.pdf
>>
>> At the very least, be sure your PC and other gear share a short, heavy, common ground.
>>
>> 3. As for protecting your PC, here's a good starting point:
>>
>> https://www.wikihow.com/Protect-a-PC-in-a-Thunderstorm
>>
>> 73,
>> Wayne
>> N6KR
>>
>
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