‰ NOW 13 WPM ‰ TEXT IS FROM SEPTEMBER 2018 QST PAGE 82 ‰ EXPERIMENTS WERE CONDUCTED USING FM ON THE PHONE BANDS. THIS MODE NEVER GAINED POPULARITY, PERHAPS BECAUSE OF THE GROWTH OF SSB, WHICH PROVED TO BE A MORE EFFICIENT AND LESS COMPLEX SOLUTION. THE SELECT O JECT WAS A NATIONAL PRODUCT THAT WAS AN ACTIVE AUDIO FILTER, USEFUL IN NOTCHING OUT HETERODYNES AND OTHER INTERFERING SIGNALS. THE 6 V POWER SUPPLY WAS A VIBRATOR UNIT FOR PORTABLE USE THAT PROVIDED ALL OPERATING VOLTAGES FROM A 6 V SOURCE. RECEIVERS AT THE TIME USED DIODE RATHER THAN PRODUCT ƒ QST DE W1AW ‰ DETECTORS. THE POSSIBILITY OF THE BFO OVERLOADING THE RECEIVER REQUIRED THE AGC CIRCUITS TO BE DISABLED WHEN THE BFO WAS ACTIVE. THE TECHNIQUE FOR CW AND SSB WAS TO USE THE RF GAIN AS A VOLUME CONTROL, WITH AF GAIN AT OR NEAR MAXIMUM. THIS PREVENTED RECEIVER OVERLOAD. WHEN SSB BECAME POPULAR, WITH ROUNDTABLE TYPE OPERATION COMMON, THE OPERATOR WAS CONSTANTLY ADJUSTING THE RF GAIN. IN ADDITION, BOTH SIDEBANDS WERE RECEIVED, WHEN ‰ END OF 13 WPM TEXT ‰ QST DE W1AW ƒ