Modifications for the ICOM - RogerK

Author: UnknowTo modify your rig for:●●●TX-144 remove R188 (1k) on the display board. 136-174 MHzTX-430 remove R187 (1k) on the display board. 420-480 MHzTX-1200 remove R186 (1k) on the display board. 1240-1320 MHzNarrow FM mode for 1200MHz install HD8 1SS355 on the display board.You do not have to reset the CPU.This modification is read 2323 times.top of page19-07-1998(IC-970) IC-970 with 9600 BaudTo use the ICOM IC-970 on the UOSAT's (9600 baud), I made the following modifications:TransmitSolder a shielded wire (I used RG174) to the anode of D16 (1SV50E). This is at the junction of R52 (470K) and C44 (.0047).Make sure to solder the shield to the adjacent PC board ground plane.ReceiveSolder a shielded wire to pin 9 of IC11 (MC3357P), again make sure to solder the shield to the PC board ground plane.Both transmit and receive are on the main unit circuit board. Make sure that you use IC11 as this is the sub band receiver. If youplan to use the IC-970 for terrestrial packet (ie. simplex on either 145 or 440) you will need to add another shielded wire to IC5,which is the main receiver discriminator.I then brought the shielded wires out the rear of the radio.I did this by removing the plate which covers the two holes located below ACC(1). In order to disconnect the wires from themodem, I installed two phono jacks in the center of the holes on the metal plate. I have used this setup with the G3RUH modem,PacComm NB96, and the MFJ-9600.I found that it was not necessary to add the 10K series resistor to the transmit audio/deviation line. On all three, with the centerof the 10K pot range as 12 o'clock, I found that about 1 o'clock to work best on for me.Note:Make sure that the DC power source for the TNC and 9600 baud modem are on a clean supply (no ripple). Several users havefound this to be the reason they could not get their modems to work. Also make sure that the TNC modem switch is set to 9600baud as this provides the 153.6kHz to the modem. The modem documentation is not very clear in this area. I run the terminalspeed at 19,200.If you have any questions, I can be reached at:Dale Hagert NM0H3881 Serpentine CircleEagan, MN 55122612-452-1030This modification is read 491 times.top of page19-07-1998(IC-DELTA1) Band expansion modification for IC-Delta1A●●●●Remove diode D14Replace diode D13 with a MA132HK (icom part#1790000830)Replace diode D15 with a MA132WK (icom part#1790000850)Reset RadioAfter mod, you get:●●118-136 MHz AM RX136-174 MHz RX/TX