Note
QST, Oct 1961, p. 146.
QST, Oct 1962, p. 139.
QST, Jun 1964, p. 183.
QST, Feb 1965, p. 122.
The Dl-1 RF Distortion Indicator assisted in the adjustment of SSB transmitters, displaying trapezoid or RF envelope patterns on its 3 inch scope tube. It operated on 160 meters at power levels of 5 watts to 2 kilowatts;. TT-1: Optional two-tone generator.