Updated: 25/05/2005
FREQUENCY 50.080.20Mhz FREQUENCY STABILITY OVEN CONTROLLED POWER 5W POWER SUPPLY 220V BACKUP N/A CONTROLLER PIC16F84 ANTENNA JPOLE HEIGHT ABOVE ROOF 3 METER HEIGHT ABOVE GROUND 50 METERS LOCATION KM71nu
- THE BEACON IS MADE FROM OLD MOBILE PHONE BASE STATION TRANSMITTING 8W ON 70MHz BAND.
- THE TRANSMITTER UNIT WAS CHANGED AND ADJUSTED TO WORK ON THE 6 METER BAND.
- THE OSCILLATOR IS BASED ON 50.025 Mhz VXO ASSEMBLED INSIDE A HOME MADE TEMPERATURE CONTROLLED OVEN (42Deg C).
- THE OUTPUT POWER IS ADJUSTED TO 5W OUTPUT TO INSURE LONG LIFE AND TO AVOID ANY OVER HEATING AND MAINTENANCE. TO LOWER THE OUTPUT POWER FROM 8W TO 5W A MODIFICATION WAS MADE TO THE POWER SUPPLY.
- THE CONTROLLER IS BASED ON THE PIC16F84 WITH A VERY SIMPLE SOFTWARE.
- KEYING IS MADE BY SWITCHING THE DC POWER TO THE PRE DRIVER STAGE TO MAINTAIN ALL OTHER STAGES STABLE AND TO INSURE FINE AND CLEAN KEYING.
- THE CONTROLLER GETS ONLY ONE INPUT SIGNAL FROM THE OVEN, THIS SIGNAL IS A STATUS OF THE OVEN READY Y/N, IF THE OVEN IS NOT READY YET, THE CONTROLLER TRANSMIT A CW TEXT THAT ANNOUNCES THAT THE XTL IS NOT STABLE YET PSE WAIT.
- THE ONLY OUTPUT FROM THE PIC16F84A IS THE KEYING SIGNAL THAT IS CONNECTED DIRECTLY TO A SMALL LOW CURRENT REED RELAY.
- THE REASON THAT THE BEACON SENDS "VVVVV" AT THE BEGINNING OF VERY TRANSMISSION IS VERY SIMPLE, IT IS TO ALLOW SOME TNC's TO SYNC TO THE CORRECT CW SPEED AFTER THE LONG KEY DOWN.
- BEACON CW TEXT IS:
"VVVVV DE 4X4SIX 4X4SIX (Transmitter will key down for about 13 Seconds & 3 Seconds no Carrier )
KM71nu, 5W, JPOLE. 4X4SIX"Listen to Beacon Recording
BEACON FRONT PANEL
BEACON INTERNAL VIEW
THE TRANSMITTER IS AT THE LEFT SIDE
THE POWER SUPPLY IS IN THE MIDDLE
AT THE OTHER SIDE INSIDE THE BOX IS THE
OSCILLATOR INSIDE THE OVEN AND
THE CONTROLLER
Last update: 25/05/2005