A couple of years ago I old on ebay a portable transmitter and receiver set of WW1 era which comprised a "spark transmitter" which was simply a doorbell- type buzzer powered by a 4.5volt "cycle lamp" battery feeding into a tapped  inductance coupled to a couple of turns intended to be fed to "antenna" and " earth ("ground" to you yanks). The rx side of this transceiver was nothing more than a "cats whisker" type receiver coupled to the same inductor combination.

My researches suggested that this "transceiver" had been designed for clandestine use behind enemyloines during the 1914 - 1918 war in europe.

 

Because I had the facilities ( and also,it has to be said; because it "was there"), I fired this combo up into all manner of loads and watched the results on a speccy.

 

Man, I can tell you it was a frightening display!

 

Unless you provided an elaborate tuned circuit the spectrum was that of a comb generator from almost DC to light !

 

I have to say that the rx performance left something to be desired but I learned something very important!

 

Somebody had to be first ! Somebody had to have the balls to design and make a "trancseiver".

 

it probably doesn't matter very much who was first but my pleasure and learning for a few weeks was derived from this concept!

 

What it taught me was that there is, in reality, nothing new in radio science or perhaps in any science or engineering endeavour!  What there is are a list of truths waiting to be discovered and explained to a following group of researchers.