Gentlemen of the air!
Thank you all for the fast response.
Nigel: Yes I remember my RAE days of the 1970s and I had just finished my apprenticeship ten years earlier as a radio and T/V engineer so was quite well up on the theory then! I still engage in it and a very active constructor of radio gear (mainly valves!)
The waveform on the scope shows a voltage representation of the modulated waveform (many signals superimposed) so I can see the modulation waveform created by the 'audio' signal. I am also aware that the carrier itself does not vary only the sidebands and these are created by the audio. I can also see that the waveform varies, when modulated at 100%, by a double amount,as you say Jim. I understand all that ... BUT.... what I had forgotten, and you guys have now cleared it up, is that I am looking on the scope and spectrum analyser, at the VOLTAGE increase. As you say it doubles (on peaks) and as this is 6dbs, then at power ratings 6dbs is X4. Yes Jim, the formulae Power = V²/R. so it is X4
I realse that this is peak power and the average, of course, would be lower.
So the questions have ben answered. Of course this increase, as you say comes from the modulator (at high level mod) will only apply with say plate/screen as any other mod will only reach carrier output (grid, controlled carrier etc).
Well, many thanks for that, and I can now confidently pass on that information with a full understanding of how it works.
Thanks to Audioguro, I understand what you say about doubling the voltage and current (power) provides the X4.
And thanks to Nigel and JimB
73's Eric GW8LJJ