‰  NOW 13 WPM  ‰

POWER AMPLIFIERS ON/OFF SWITCH.  FOR AUTOMATIC REPEATER OPERATION, WE DO
NEED THE VALID SIGNAL CONTROL LINE.  MOST DVB T RECEIVERS INCLUDE AN LED
FRONT PANEL INDICATOR THAT CHANGES FROM RED TO GREEN WHEN THE RECEIVER IS
RECEIVING A VALID DVB T SIGNAL.  THUS, WE NEED TO GET INSIDE THE RECEIVER,
REMOVE THE LED DRIVE SIGNAL FROM THE CIRCUIT BOARD, AND BUFFER IT WITH A
SIMPLE TRANSISTOR CIRCUIT TO PROVIDE AN OPEN COLLECTOR TO GROUND LOGIC
OUTPUT.  THIS IS THEN USED TO CONNECT TO THE PUSH TO TALK PTT INPUT ON THE
ƒ  QST DE W1AW  ‰
RF LINEAR POWER AMPLIFIER TO KEY THE REPEATERS TRANSMITTER ON AND OFF.
PUTTING IT TO USE YOU MAY BE WORRIED ABOUT MEETING THE FCCS REQUIREMENT TO
IDENTIFY TRANSMISSIONS AT LEAST EVERY 10 MINUTES, BUT THIS IS SIMPLE.  WITH
DVB T, YOU ARE AUTOMATICALLY IDENTIFYING YOUR SIGNAL, NOT EVERY 10 MINUTES,
BUT WITH EVERY FRAME OF VIDEO.  THE DIGITAL DATA STREAM INCLUDES A HEADER
OF METADATA DESCRIBING THE MODULATION PARAMETERS USED AND THE CALL SIGN OF
‰  END OF 13 WPM TEXT  ‰  QST DE W1AW  ƒ