Even the most knowledgeable operator now needed to re skill, to learn how the 1914 -18 wartime invention of dual dial tuning, by Major Armstrong, was to become basic to Radio reception over the next eighty years. Armstrong's ingenuity also embodied a second development called reflexing. This was pushed to its outer limit by making the second valve produce another and different signal. This second function modulated a powerful internal signal continuous (C W continuous wave) signal just above the high end of the audible frequency range. Blending or harmonising this internal signal with the high frequency signals received by the early Ham Radio operators made the weak distant headphone audible and people thought it was ok to call them amateurs.
For those early radios to select the required signal out from any competing noise, users needed to adjust them by turning the two selector dials, one with each hand. Advanced valve operation and a newly found method called reflexing, still in use now, to make a triode valve amplify while simultaneously performing two different tasks. A powerful signal created by one valve was generated across a honeycomb coil called a harmoniser, allowing this internally generated continuous wave signal to be modulated by the amplified signal selected by the tuned aerial coil. Tuning required reference to the two cardboard charts inserted behind the pointer hands, to ensure the difference in frequency between the oscillator maintained in step (in harmony) with and the amplified distant signal. The resultant signal now remains just above the high end of the audible hearing range. This functioned in the same way as the signal we now know as the intermediate or I F frequency. This amplified signal could then be doubled back to pass through the first valve as a week audio signal only just audible in headphones. This weak signal then achieved a three times voltage gain when it passed through a 1 to 3 coupling transformer then to be increased by the second valve, only then gaining enough to power a very small Brown speaker.