[Nick Forder]

I think that the key thing here is that it offers a different perspective from that usually encountered, and may well be more accurate in terms of gauging the actual effectiveness of the methods employed.
It is true that the author appears to be not overly enamored of the RFC, and is seeking to avoid spending too much time on what he regards as a tangent, but that doesn’t make the comments any less relevant.
It is known that the RFC used airborne wireless sets prior to the Sterling (or Stirling !), and it remains unclear – to me at least – when the Sterling was issues as a standard (as opposed to experimental) set, and when it replaced previous sets. The implication is around September, 1915, in time for Loos, but I am unable to confirm that.