Hello all:

First, I made a mistake by only quoting Wikipedia in part. The article is much longer than the fragment I posted here. My mistake, please excuse me. Please follow the link I provided to the full article.

Next, my interest was in the development of the superhet, from (I guess) about 1915 to when it became the dominant technology (so let's say until the time Drake designed the "K" series). Somewhere around 1931 .. 1934.

I found other references (ie not Wikipedia) that recounted (in outline) the same history I read in Wikipedia. As others wrote here: radio direction finding depends primarily on measuring angle, not signal strength.

On a side issue (RDF related): Beryl Oliver (I knew her son a little) told me she approached the military at the beginning of WWII to work in signals (or radio). They told her: go to the local postmaster. Learn morse. When you can send/receive morse at 17wpm come back here. She worked in RDF. I don't know if this was RAAF or navy. I recall seeing a photo of her standing beside an impressive console in uniform. She told me aircraft would contact her (when lost) and ask for a bearing. She would reply. At times (she told me) she told them: Continue to fly on (some course). I will tell you when you are over my station. (She told me the signal dropped to a minimum when the aircraft was overhead.) She also told me she was one of several stations engaged in tracking the IJN. I greatly regret not recording these conversations.

Radio technology was primitive during WWI. In our local radio club library we have a set of admiralty books where capacitance is measured in 'jars'. As I understand it, a Leyden jar has a capacity between 1 to 2 nF.

73 to all from VK

Leslie