[kwlug-disc] Home made indoor TV Antenna
jvj at golden.net
Thu May 1 22:53:27 EDT 2014
On 2014-05-01 16:14, John Johnson wrote:
> ** Almost nothing will protect against a direct lightning strike as
> the energy to be dissipated is just too high. Typical protection
> circuits are intended to protect against lightning induced voltages,
> i.e. those voltages induced in conductors near a lightning strike and
> induced by the rapidly changing magnetic field around the strike.
On lightning and lightning induced surge voltages:
In the days of dial-up (and expensive PC hardware) I preferred external
modems as I considered these to be sacrificial as compared to the PC.
Inside of 10 years, I replaced 3 modems on my sister's PC when the
modems were bricked as a result of lightning induced surges during storms.
She lived in Waterloo near Weber and Marshall on a lot that backed onto
a park and where there large and high trees. And a high water table.
I also replaced a couple of dial-up modems at my place until I went DSL.
I and still use a rental DSL modem for the same reason, sacrificial
And, a few times, I have had the DSL modem replaced by the ISP after it
was bricked during a storm.*
I also have a few trees in my area. And the phone lines through and near
I prefer to have the lightning induced voltages reduced by the external
equipment before the cabling brings the voltages into the box or router.
* I know the cost of DSL modems has dropped over the years and that
replacement units can be had for much less cost than before.
PS: In about 1978, I gained a healthy respect for lightning, having been
dispatched by my employer to travel to the Pembroke area to repair a
rural T1 carrier system that had been damaged by a lightning strike in
the area. I had to replace most of the circuit boards in the 2 metre
high rack mounted system as well as the backplanes. And then wirewrap
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