On Sep 16, 4:02 pm, wrote:

1. How does Strikefinder technology estimate range and direction to a
lightning strike (my original question)?

Direction is measured using ADF technology, with an internal magnetic-
heading sensor to compensate for the aircraft's heading changes
without a connection to any other instrument.

2. If Strikefinder technology operates in the AM band, why?

Plenty of strong static bursts (sferics).

3. How are range and direction to/from lightning strikes determined?

Exact range determination would require triangulation using two or
more sensors over a wide baseline. All single-sensor lightning
detectors on the market (as far as I know) make a rough range estimate
by assuming that all lightning bolts are of the same intensity and
applying the inverse-square law to derive distance; this can lead to a
large range error for a single bolt and radial 'stretching' of the
storm cell when there are numerous strikes from a cell. The display
therefore has to be interpreted very cautiously and should be used for
avoidance, not penetration of a line or area of cells.

The Strikefinder web site (http://www.insightavionics.com/manuals.htm)
has PDF files of their manuals; look at page 34 of the user's guide to
see an example of cell stretching.