Jim Weir wrote in
:

Howzat?

As usual, pretty durn good.

From my conversations with a couple of the BFG guys that worked the "series
I to series II" transition, the first real trick was to accurately
characterize the lightning RF data. In several parts of the country they
put up triangulation systems (ground based). This allowed them to
accurately pinpoint any strikes in area. They then outfitted a couple of
planes and flew them around the outskirts of any storms that moved through.

The result from the planes was the recorded RF broad-spectrum energy
patterns from strikes at known distances. It was from this that they found
that they could do a good estimate of distance by essentially matching the
basic pattern to one of several basic shapes (this is partly how they
exclude cloud-to-cloud) and then comparing the difference between the
"paradigm" shape and what was actually measured.

The rest was just a lot of high-speed (for the time) DSP.

jmk