ICOM IC-229H EXTENDED BAND MODIFICATION:

There are a couple of very simple mods you can make to the ICOM
IC-229H mobile transceiver to extend the receive and transmit
frequency bands beyond the normal 2-meter range.  I have
performed these mods on my radio and they work with no adverse
effects (that I've noticed yet).  Not only were the 2-meter bands
extended, but it gained additional receive bands in the 300MHz
and 800 MHz regions.  The unit switches to AM mode when receiving
below 136 MHz, so you can pick up aircraft frequencies (approach
control and ATIS).  The final specs are as follows:

    Rx:  118 - 174 MHz,   340 - 380 Mhz,   870 - 890 MHz
    Tx:  136 - 174 MHz

WARNING:  Be VERY careful about transmitting on the extended
range since this is where police and emergency services are.  You
don't want to break in on police repeaters!  Also, the radio
specs are not guaranteed on the extended ranges and your antenna
probably won't be properly matched. 

NOTE:  I can not and will not be responsible for any damage
caused by anyone performing these mods.  Be aware that these mods
will void your warranty. 


MODIFICATION PROCEDURE:

Take care when disassembling the radio and performing these mods,
the components are very small and connecting wires are very thin.

1. Remove the three front panel knobs by pulling them straight
off.  Carefully unscrew the ring on the microphone connector. 

2. Remove 4 screws from bottom cover plate and lift off cover. 

3. Remove 4 screws from top cover plate and lift the cover off
and to the side, being careful not to stress the wires to the
speaker mounted on the top cover. 

4. Remove the 4 screws (2 top, 2 bottom) holding the front
plastic bezel in place.  Pull the bezel straight off. 

5. Remove the 3 screws holding the front panel assembly in place. 
GENTLY fold down the front panel assembly to access the rear
component side. 

6. Refer to the diagram below.  Locate diode D5 (mounted on end)
to the right of center on the board.  Clip the exposed wire lead
on the diode (do NOT try to unsolder it) and bend each end of the
cut wire away from each other to prevent any inadvertent
connection.  You now have extended the receive frequency range -
if that is all you want, reassemble the radio now. 

7. To extend the transmit frequency range, locate the two bright,
unsoldered semicircular copper pads located about 1/2 inch to the
right of diode D5.  With a micro-tip soldering iron and thin
solder, connect a solder jumper across these pads.  You won't
need any wire for the jumper, and don't apply too much heat.  I
just put a blob of solder on the tip of the iron first, and then
applied it to the circuit pads.  That's it, you've now extended
the transmit range. 

   VIEW LOOKING DOWN ON     /***********************************
     THE CIRCUIT BOARD      /----------]                       *
     AFTER IT IS FOLDED     /  display ]   . . D?              *
     DOWN AWAY FROM THE     /----------]   .o. D5              *
     RADIO CHASSIS:         /              . . D?    = (pads)  *
                            /***********************************

8. Reassemble the radio in reverse order of the above steps.  Be
careful when folding the front panel assembly back in place that
none of the wire bundles are pinched between the front panel and
the chassis.