Icom - 9350 Protocol Converter (ic9350)

This project is to develop a way to use an Codan 9350 automatic antenna with an Icom radio. Most Icom radios support the Icom AH-4 ATU, so the approach is to design a protocol converter that converts the protocol used by the 9350 to the AH4 protocol to allow full integration with the Icom radios that support the AH-4.

The ic9350 Protocol Converter uses the interface uses the radio's ATU interface in the way that Icom intended, and will not disrupt radio operation .

Features

Self powered from Icom radio tuner port, supplies power to 9350;
Emulates AH-4 so that the Icom radio enables its external ATU support (eg TUNE button, external interface);
Converts requests for tune from the Icom to 9350;
Requests tune carrier (typically 10W unmodulated carrier, subject to individual radio configuration);
Monitors 9350 for completion;
Signals success or failure to the Icom radio;
Simple, low parts count, reliable device based on 8 pin inexpensive microcontroller (12C508, 12F509);
Supports In Circuit Serial Programming of flash device (12F509);
Microcontroller sleeps (clock not running) when tune completes to reduce RFI;
Status LED to show tune status and signal error conditions.

Not supported

SCAN
- The SCAN feature of the 9350 must be disabled on PTT, which is not possible using only the Icom ATU interface. The Icom radios do not directly support external signal of scan mode on any interface.
RESET from radio
- Aborting a tune in progress is not consistently implemented in various models. Some send a logical signal to the ATU and some just drop carrier. Of the types that just drop carrier, the 9350 will fail due to inadequate RF and the ic9350 should pass the fail back to the radio.
VSWR high
- Icom radios have features that dispense with the need to respond to the VSWR high signal from the 9350. The features are Tuner Autostart (ATU starts when VSWR > 1.5-3:1), and PTT Start (first time PTT is operated on a new frequency).

Error conditions detected:

9350 not connected;
Invalid START signal;
Invalid 9350 signals prior to initiation;
RESET received from radio.

Table 2: STATUS LED
Status	Description	Comment
Steady on	Tune success
1 flash	Tune failed	Tune fail signalled by 9350
2 flashes	START signal < 250ms	RESET received from Icom
3 flashes	/TUNE low prior to initiation	Tested without internal pull-up - fault could be no connection to 9350.
4 flashes	Timeout waiting for /START, /TUNE at completion	25 second timeout

Table 2 shows the STATUS LED indications. Note the 25 second timeout waiting for START, /TUNE, /IND at completion of a tune process,

Table 2: Pin assignment of 6 pin radio connector on ic9350 for Codan NGTcable.
Pin	Signal
1	/TUNE
3	/IND
4	+12VDC
6	GND

Table 3: Pin assignment of 4 pin connector on Icom tuner interface.
Pin	Signal
1	/KEY
2	/START
3	+12VDC
4	GND

Prototype

Fig 1: Assembled PCB

Fig 1 shows an ic9350 prototype constructed on a PCB design by Mark Kyle, VK4KZK. The boards are designed to take 4 Pole PC Mount Plugable Header (Jaycar HM3104 and HM3124) for both radio and antenna connections (though in this prototype, the radio side is direct wired).

Fig 2: Complete ic9350

Fig 2 shows the ic9350 complete in a UB5 Jiffy box (box dimensions 83 x 54 x 31mm not including connectors etc). To connect to the 9350, and standard Codan cable is used, the radio end connector is cut off and the appropriate four wires are terminated on the plugable header at the right hand side of the picture.

Fig : 3

Changes

Version	Date	Description
1.01	10/12/2007	Draft.
1.02
1.03

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