Many, many years ago when I was an apprentice I was privilidged to visit a BBC World Service transmitting station. Whilst there one of the engineers demonstrated a quick test to see how well one of the HF Transmitters was doing. This was a kind of output and modulation check...
He contacted the feeder and drew a huge arc off of it. The length of the arc gave an indication of the power and the modulation could be heard audibly on the arc, thus giving an indication of modulation...
There began my love of very high power HF stuff and Napier Deltic diesel engines (as used in the Deltic Railway Locomotive) which were used for standby power generation
