Going back to your query RNinMunich, something over thirty years of my life was as an engine
er officer in the RN. Half in sea going appointments and the other half spent mainly directing ship support and maintenance. Great times!!
I spent a bit more time today reading up about DF system
s. Loop antenna on Wikipedia was interesting. it seems to me that a simple manual
DF loop would be a feasible option for the teardrop; it was certainly that on many varied aircraft
at that time (inc the Wellington). Also, thinking about the size of the teardrop, it may be small for a DF loop, but comparing it to the other navigation light
s, it's really too small to be one of them! I love chasing all over the net trying to find positive solutions to little mysteries!