‰ NOW 30 WPM ‰ TEXT IS FROM JUNE 2015 QST PAGE 55‰ UNIT IS INTERCONNECTED TO THE REMOTE TUNER VIA A 25 CONDUCTOR CABLE UP TO 130 FEET LONG LONGER DISTANCES REQUIRE HEAVIER WIRE. THE REMOTE TUNER FIGURES 2 AND 3 CONTAINS A BALANCED NETWORK WITH SHUNT CAPACITORS AT EACH END OF THE TWO INDUCTORS, ONE ON EACH SIDE. THE INDUCTORS, ADJUSTABLE TOGETHER IN 32 STEPS, AND THE INPUT CAPACITANCE, ADJUSTABLE IN 256 STEPS ARE SELECTED BY RELAYS SWITCHING IN FIXED ELEMENTS. THE ANTENNA SIDE CAPACITOR IS A ROTARY AIR DIELECTRIC VARIABLE CAPACITOR WITH A STEPPER MOTOR TO ADJUST IT IN 200 INCREMENTS. A GAP TYPE LIGHTNING ARRESTOR IS LOCATED AT THE ANTENNA TERMINALS. ON THE RADIO SIDE IS A 1 1 CHOKING BALUN THAT, WHEN TUNED, OPERATES WITH A 50 IMPEDANCE ON BOTH ENDS FOR MAXIMUM EFFICIENCY. THE OUTDOOR COAXIAL CONNECTOR IS A TYPE N SOCKET, A GOOD CHOICE FOR OUTDOOR USE. THE AT 615B REMINDS ME OF THE CLASSIC MOTORIZED BALANCED ANTENNA TUNER DESIGN PRESENTED BY RICHARD MEASURES, AG6K, IN QST YEARS AGO/. THE AT 615B IS CONFIGURED AS A BALANCED NETWORK, RATHER THAN BALANCED L NETWORK, TO ALLOW IT TO MATCH LOADS BOTH ABOVE AND BELOW 50. THE ORIGINAL MEASURES DESIGN HAS A SINGLE VARIABLE CAPACITOR ON THE OUTPUT ‰ END OF 30 WPM TEXT ‰ QST DE W1AW ƒ