[time-nuts] time-nuts Digest, Vol 100, Issue 114

Bob Camp lists at rtty.us
Mon Nov 26 20:26:33 UTC 2012


Hi

There are commercial sites that routinely take multiple hits per hour
without going off line. It's not cheap, and it's not easy, but by no means
is it a "noting can save you" sort of situation.

Bob

-----Original Message-----
From: time-nuts-bounces at febo.com [mailto:time-nuts-bounces at febo.com] On
Behalf Of M. Simon
Sent: Monday, November 26, 2012 3:07 PM
To: time-nuts at febo.com
Subject: Re: [time-nuts] time-nuts Digest, Vol 100, Issue 114

If you get a direct hit pretty much nothing can save you. Except luck.
Because, when you are trying to get signals in on the one hand and keep
lightning out on the other, strange things can happen. 

 
I had a long wire about 100 ft long (outdoor length probably on the order of
80 ft.) around 10 ft above ground (year about '74 - Carbondale, Illinois). A
Lafayette Radio Antenna Kit IIRC.  A spark plug lightning arrestor (gapped
to .010) on the end of an 8ft pipe pounded into the ground and then into the
shack with a knife switch ground for use  during storms. 

During a storm with every thing in order - knife switch closed - antenna
thus grounded - I took a direct hit. It caused a 3 ft ball lightning to form
inside. It was green and moved slowly in my direction as I backed away. I
think it lasted about a minute but time sense in such situations is not very
good so it might have been 10 or 20 seconds. Total movement from inception
to collapse - around 10 ft. No eqpt. was damaged. XMTR was a Johnson Ranger
and the RCVR was a Hallicrafters. Can't recall the model. It would have been
a similar price rage for the time - both bought used. 

So ball lightning is real. I found out up close and personal. 

Simon

Engineering is the art of making what you want from what you can get at a
profit.


Message: 2
Date: Mon, 26 Nov 2012 10:18:34 -0800
From: Mark Spencer <mspencer12345 at yahoo.ca>
To: Discussion of precise time and frequency measurement
    <time-nuts at febo.com>
Subject: Re: [time-nuts] Surge Arresters
Message-ID: <CF4183AD-9C33-4012-8563-B5575DEBA4F8 at yahoo.ca>
Content-Type: text/plain;    charset=us-ascii

I don't use one on my gpsdo feed line.   The shield of the feed line is
grounded prior to it entering the house and I don't live in a lightning
prone area.  The gps antenna I use apparently has diode protection to
provide some immunity to near by lightning strikes.  Most of my radio
antennas are dc grounded.  I also had a dedicated roof top ground system
installed during some prior home renovations that the coax shields of my
roof top antenna(s) are connected to.   This ground system is in turn
connected to the electrical service ground out side of the house.  I'm
hopeful the roof top ground will be a more attractive path to ground for
lightning than the shields of the feed lines that run into the house that
are connected to gpsdo's and radios that are in turn grounded via the
electrical system in the house.

If I see a surge suppressor for a decent price on eBay I might re consider
getting one, but I'm unsure if it would make much difference in my
circumstances in the event of a direct hit.   I'm primarily interested in
protecting the house and it's occupants.   The survival of the radios is a
fairly low priority to me.

I hope I never get to find out what happens if my roof top antennas get hit
by lightning.

Regards

Mark Spencer

Sent from my iPad


------------------------------


>
_______________________________________________
time-nuts mailing list -- time-nuts at febo.com
To unsubscribe, go to
https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts
and follow the instructions there.





More information about the time-nuts mailing list