Owen Duffy wrote in
:

This sets me thinking of a way to calculate a lower frequency limit to
the loss model when I generate it, so that I can store that limit in
the database and prevent calculation below that frequency.

I have just analysed the tllc database contents to find cases where the
modelled error is more than 10% different to the data points on which the
regression was based.

There are a few cases, they are all copper clad steel inner conductors
(some of the RG6, RG59, RG174, RG316). I need to implement a lower
frequency limit for model validity for each cable type.

An alternative approach to retain some lower frequency results is to use a
cubic spline interpolation... but it has its own problems.

Owen