PMR 446

PMR IS BASICALLY A MOBILE COMMUNICATION SYSTEM FOR BUSINESSES AND PRIVATE INDIVIDUALS. IT CAN BE USED BY THE GENERAL PUBLIC FOR SUCH ACTIVITIES AS HIKING / RAMBLING/  BABY ALARM AND GENERALLY KEEPING IN CONTACT.THERE ARE EIGHT FREQUENCIES INVOLVED. THE TRANSCEIVERS ARE LICENSE EXEMPT AND HAVE A POWER OUTPUT OF ABOUT 500 mW, GIVING A  MAXIMUM RANGE OF ABOUT 2 MILES, WHICH WILL BECOME DEGRADED  IN BUILT UP AREAS OR IN MOUNTAINOUS AREAS, WHEN OUT IN THE COUNTRY SIDE.THE EIGHT CHANNELS HAVE BEEN SET AS A STANDARD THROUGHOUT THE U.K AND EUROPE. THEY ARE SPACED 12.5 KHZ APART. PLEASE NOTE THAT CHANNEL 1 & CHANNEL 2 AT PRESENT CAN NOT BE USED IN FRANCE.THESE CHANNELS ARE NOT MEANT TO BE MONITORED BY ANYONE USING A SCANNER RECEIVER, SAME AS THE MOBILE PHONE SEGMENTS AT 800 - 900 MHz WERE NOT MEANT TO BE MONITORED ( YOU CANNOT LISTEN TO THESE FREQUENCIES ANYMORE ANYWAY, AS THEY ARE ALL DIGITISED ).TO MINIMISE INTERFERENCE BETWEEN USERS EACH CHANNEL HAS 38 'CTCSS' CODES ( CONTINUOS TONE CODE SQUELCH SYSTEM ) WHICH CAN BE SET BY THE USER FOR EACH CHANNEL AND WILL LIFT THE SQUELCH.SO ITS IMPORTANT IF YOU ARE TRYING TO COMMUNICATE WITH SOME ONE ON A CHANNEL, TO SET BOTH RECEIVE AND TRANSMIT HANDHELD TRANSCEIVERS TO THE SAME CTCSS, OR YOU WON'T BE ABLE TO COMMUNICATE WITH THAT PERSON. SO IT FOLLOWS THAT IF SOMEONE ELSE IS USING SAY CHANNEL 5 IN YOUR VICINITY, BUT HAS A DIFFERENT CTCSS SET THEN IT WON'T LIFT THE SQUELCH ON YOUR TRANSCEIVER AND YOU WON'T EVEN KNOW THEY ARE THERE. WITH CB RADIO YOU ARE MOSTLY LIKELY TRYING TO COMMUNICATE WITH COMPLETE STRANGERS, PMR446 IS NOT INTENDED TO BE USED IN THAT WAY, AND IS REALLY TO MY MIND FOR KEEPING IN CONTACT WITH KNOWN PEOPLE.THE PMR446 INTERNET GATEWAY SYSTEM BEING A DIFFERENT BALL GAME.

BELOW IS  A SCREEN SHOT OF THE SOFTWARE BY M0ZPD

TO USE THE ABOVE SOFTWARE AND SET YOUR SELF UP AS A ' GATEWAY REPEATER STATION ', YOU NEED TO INTERFACE YOUR PMR TRANSCEIVER TO YOUR PC ( USING THE MICROPHONE SOCKET TO THE LINE OUT ON THE COMPUTER  SOUND CARD AND THE LINE INPUT SOCKET ON THE SOUND CARD TO THE TRANSCEIVERS SPEAKER SOCKET ) ALSO YOU NEED TO EMAIL THEM AT EQSO TO GET REGISTERED AND HAVE THEM GIVE YOU A CALL SIGN I.E SOMETHING LIKE " UK001-L"  ( SEE ABOVE PANEL) ANYONE WITHIN RANGE OF YOUR PMR TRANSCEIVER WILL BE ABLE TO GET ACCESS THROUGH YOUR RADIO AND COMPUTER ONTO THE INTERNET CONNECTING TO ANOTHER GATEWAY LINK, MAYBE IN AUSTRALIA AND OUT TO  SOMEONE'S HAND HELD PMR TRANSCEIVER. WHEN YOU ARE OUT OF THE HOUSE YOU CAN THEN BENEFIT FROM USING YOUR HANDHELD TO  GAIN ACCESS THROUGH SOMEONE ELSE'S SET-UP AND ONTO THE INTERNET AND HOPEFULLY MAYBE TO SOME ONE ELSE USING A HAND HELD TRANSCEIVER. PLEASE VISIT THEIR WEB SITE AND READ THE DOCUMENTATION BEFORE SETTING THINGS UP.

COM PORT SWITCHING

I FOUND THAT WHEN I WAS USING THE ABOVE SOFTWARE, I WAS MISSING THE FIRST FEW SECONDS OF THE OTHER GUYS " OVER " BECAUSE THE VOX WAS TO SLUGGISH.SO I BUILT THE BELOW INTERFACE, SO THAT THE SIGNAL FROM THE COM PORT AUTOMATICALLY SWITCHES THE PMR TRANSCEIVER BETWEEN TRANSMIT AND RECEIVE. ALL OF THE PARTS TO BUILT IT CAN BE BOUGHT AT MAPLIN. IF YOU HAVE A PROBLEM OBTAINING THE SFH618-2, THE 4N25 OR 4N27 WILL ALSO WORK OK. . SOLDER THE TWO WIRES ACROSS THE PTT SWITCH OF THE RIG.THE COM PIN NUMBERS RELATE TO A 9 PIN COM PORT SOCKET ( DB9 )

CONNECTING THINGS UP

NOTE - DON'T USE THE SOUNDCARD MIC INPUT - YOU WILL HAVE FAR TO MUCH GAIN