[time-nuts] Loran, GPS, Lightning, Timing

[Chris Albertson]

There is actually a lot of information on lightening observation.  If you
have access to a university library.  Some public libraries have on-line
databases you can search too.   Google is not so good at this as most of
the papers are in journals where you need a subscription, or more likely a
library that has a subscription.

I used to own a sail boat and took an interest in lightening and red a
bunch about it a few years back.  You can guess why.  On a boat on the
ocean you are very exposed, If a storm comes you can't simply get off the
water so there you are living under a 65 foot aluminum pole which is the
tallest conductor for miles and miles around.   So what to do about it?

I looked around and the most of the answers where coming from the
University of Florida.  They have some good "How To" publications if you
want to survive direct hits (to cover the sailing example) and also theory
but about detection, they have a "lightening observatory" there are there
are papers describing the instruments.   They observe the normal LF but
also up in VHF and even x-ray detectors.   Techniques are described for
determining the types of strikes (polarity) and some time they cn see
plrity reversals in cloudsand cloud to cloud discharges.    Once you find a
few survey papers they will have a long list of citations and you can hunt
down those papers.     A good search phrase is *"Lightning Observatory in
Gainesville "*

I think before anyone builds any detector it might help ask what data you
want.  Are you wanting to simply detect that lighting is nearby so you can
disconnect equipment or do you want to characterize the lightening in some
way?    It turns out almost always you need to know the location and this
means you need to make observations from sites that are some miles apart.
What a good TN application.  You need to have good time so you can combine
the measurements.

What I learned about the boat is that I needed a VERY good conducting path
from the mast to the saltwater.  This was made somewhat easy on my boat
because I had a 7,000 pound lead keel in contact with water (except for
some paint) and the mast was keel stepped.  Give the current a nice easy
straight line path and it will take it and not bother you.


On Sat, Jun 28, 2014 at 6:52 AM, Brian Lloyd <brian at lloyd.com> wrote:

> On Fri, Jun 27, 2014 at 11:34 PM, DaveH <info at blackmountainforge.com>
> wrote:
>
> >
> > I also searched for "Lightning" and found nothing about detecting nearby
> > strikes, only about protection. Searched from around 1980 back through
> > 1940.
> >
>
> There are a number of products on the market that make use of lightning
> detection and ranging. The BF Goodrich "Stormscope" is based on that. There
> have to be some documents around on its design. It is, in essence, a LF ADF
> and somehow qualifies the envelope to deduce range to the strike which it
> then displays to the pilot.
>
> --
> Brian Lloyd
> Lloyd Aviation
> 706 Flightline Drive
> Spring Branch, TX 78070
> brian at lloyd.com
> +1.916.877.5067
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-- 

Chris Albertson
Redondo Beach, California