How to use a Syntor X mobile on APRS

and have 150 watts output!!!


1.  Program the Syntor X EEPROM as a 136-153 MHz split radio.  It's best to start
with a "new" template and assign 144.39 as the default frequency.  Disable scan, set
it to CSQ (carrier squelch) for TX and RX, and set all other options to OFF.  The
time-out timer should be 1 minute (wish it would let us select 10 seconds like I use
on my Maxtrac/Radius/GM300 radios!)

2.  Reinstall the EEPROM and open up the VCO cover (4 screws, and pry it up.)
With the radio front connector facing you, find C1436 (above and to the right of the
screw, parallel to the front cover) and C1435 (directly below the screw, also
parallel to the front cover.)

UPDATE:  Different boards have different numbers for the capacitors.  They are
always in the same places on the board.
Jumper C1436 with a 47pf capacitor (preferably a chip
cap, but other small cap will work) and jumper C1435 with a 75pF capacitor.
You should now have VCO lock, as indicated by a dark LED on the other side of
the board during both TX and RX.

UPDATE:  It also helps to jumper Q600's collector on the receiver board (range select)
to ground.  Your steering line voltages on TX and RX should be in the middle of the
1.3 to 9.0 volt range.

3.  Generate a weak signal on 144.39 - you should hear it at around 10 microvolts.
Don't panic yet.  Find the helical adjusting screws (the ones that say "DO NOT ADJUST")
and break the plastic coating off the ends.  Then tune each one for a peak in received signal.
You should see about .2 microvolts for 20 db quieting when done.

4.  Key the transmitter and inject audio or yell into the microphone.  You'll see only 2.5 kc
deviation.  Again, don't panic.  Readjust the deviation control (diagram above) for 5kc.
Also set the power control for desired output.
Road map:  Power set is the hole on the left.  It is backwards (CCW = increase)
Dev adjust is the hole BELOW the shield at the bottom of the picture.
The hole on the right is deviation compensation - do NOT adjust unless you're using
digital coded squelch (Motorola DPL) !
On the far left, Ref Osc Adjust is your master frequency trimmer.
On the "common circuits board" (other side of radio, this same board)  if you loosen the
three screws and swing the board out you will find a pot closest to the heatsink end of
the radio.  This is "current limit adjust"  and you may need to tweak it for maximum power.

5.  Connect the wires to the front connector as shown:
        Pin            Function
        4                PTT, KPC-3 pin 3
        2                RX audio, KPC-3 pin 5
        15,5,A        + 12 volts, KPC-3 pin 7
        10,8,B        Ground, KPC-3 pin 6
        27               TX audio, KPC-3 pin 1

There you go!  You should have the loudest digi around, or the best backwoods
tracker available!  Just remember that you'll be drawing about 30 amps at 150 watts,
so use the correct size wire!

6.  Frequency steering:  If you want 16 channels, your BCD data is from this table:
Ground control head connector pins 12,16,23,29 to make it go into BCD mode.
For 32 channels, your BCD table is now changed to  this table: Use the "Repeat/Talkaround"
or "A/B switch" option when programming the EEPROM module.