IC-R7000 SkyCAT Driver

Development Notes & Community Contribution Guide

Prepared by N1BAQ

Background

The Icom IC-R7000 wideband receiver had no SkyCAT command definition file, making it incompatible with SkyRoof’s native CAT control. The goal was to get SkyRoof to control the R7000 for Doppler-corrected satellite tracking.

Why Not rigctld/hamlib?

We started with hamlib’s rigctld since it lists the R7000 as model 3040. Basic communication worked - rigctl -m 3040 -r COM4 -s 1200 successfully returned frequencies. However rigctld failed with SkyRoof because:

  • SkyRoof sends a V VFOA (VFO select) command during setup
  • The R7000 rejects it with error -9 (command rejected by rig) - it is a receiver with no VFO A/B concept
  • SkyRoof disconnects on that error and keeps retrying endlessly

SkyCAT was the correct solution since it uses a custom command definition file that only sends commands the radio actually supports.

Building the JSON - Where We Started Wrong

We built IC-R7000.json by modifying the IC-706MKIIG.json that ships with SkyCAT, substituting what we believed was the R7000’s CI-V address. That address - 52h - came from hamlib’s own model database for the R7000 (model 3040).

This was wrong, and it cost hours of debugging.

Hamlib uses 52h internally but apparently handles the address mismatch gracefully enough to still get responses during direct rigctl testing. This masked the real problem completely - the R7000 was receiving every command, echoing them back on the CI-V bus, and silently ignoring them because they were addressed to the wrong radio.

The symptom was maddening: SkyCAT connected, setup succeeded, frequency write commands returned OK, but the radio never changed frequency.

The R7000’s actual CI-V address per its own manual is 08h - not 52h.

If you are starting from scratch, go to the R7000 manual first - not hamlib’s model database.

Key Discoveries

1. CI-V Address is 08h - NOT 52h

The single most important finding. The R7000 manual explicitly states the default CI-V address is 08h. Hamlib lists it as 52h, which is incorrect. Using 52h causes the radio to echo all commands but silently ignore them.

2. reply: null Required Throughout

The R7000 at 1200 baud is slow. SkyCAT’s default 1-second timeout expires before the radio’s acknowledgement arrives. Setting “reply”: null on all commands lets SkyCAT fire-and-forget rather than waiting for confirmations that time out. In practice the radio responds correctly regardless.

3. Setup Command Needs reply: null

SkyCAT requires a setup block in the simplex section or it fails to initialize. A simple read-frequency command works as the setup ping, but with “reply”: null to avoid the timeout.

4. echo: true is Correct

The R7000 echoes all CI-V commands back on the bus - standard CI-V behavior for older Icom radios. Setting “echo”: true tells SkyCAT to expect and discard the echo before looking for a reply.

5. Remote Switch Must Be ON

The rear panel REMOTE switch on the R7000 must be in the ON position for CI-V commands to be acted upon. With it OFF the radio still echoes commands but ignores them - a symptom identical to the wrong address problem, making it very confusing to diagnose.

6. SkyRoof CAT Delay Setting

Set the Delay in SkyRoof’s CAT Control settings to 500-1000ms initially when working with the R7000’s slow 1200 baud interface.

Final Working IC-R7000.json

Place this file in the Rigs folder of your SkyCAT installation:

{
  "id": 3040,
  "echo": true,
  "default_baud_rate": 1200,
  "cross_band_split": false,
  "bad_reply": [
    "FE",
    "FE",
    "E0",
    "08",
    "FA",
    "FD"
  ],
  "comment": "Icom IC-R7000. CI-V address 08h (NOT 52h as in hamlib). reply:null required due to 1200 baud timeout.",
  "simplex": {
    "setup": {
      "messages": [
        {
          "command": [
            "FE",
            "FE",
            "08",
            "E0",
            "03",
            "FD"
          ],
          "reply": null,
          "comment": "Read frequency as setup ping"
        }
      ],
      "restriction": "when_setting_up"
    },
    "read_rx_frequency": {
      "messages": [
        {
          "command": [
            "FE",
            "FE",
            "08",
            "E0",
            "03",
            "FD"
          ],
          "reply": null
        }
      ],
      "restriction": "when_receiving"
    },
    "read_tx_frequency": null,
    "read_rx_mode": {
      "messages": [
        {
          "command": [
            "FE",
            "FE",
            "08",
            "E0",
            "04",
            "FD"
          ],
          "reply": null
        }
      ],
      "restriction": "when_receiving"
    },
    "read_tx_mode": null,
    "read_ptt": null,
    "write_rx_frequency": {
      "messages": [
        {
          "command": [
            "FE",
            "FE",
            "08",
            "E0",
            "05",
            null,
            null,
            null,
            null,
            null,
            "FD"
          ],
          "reply": null,
          "command_param": {
            "format": "BCD_LE"
          }
        }
      ],
      "restriction": "when_receiving"
    },
    "write_tx_frequency": null,
    "write_rx_mode": {
      "messages": [
        {
          "command": [
            "FE",
            "FE",
            "08",
            "E0",
            "06",
            null,
            "FD"
          ],
          "reply": null,
          "command_param": {
            "format": "Enum",
            "values": {
              "LSB": [
                "00"
              ],
              "USB": [
                "01"
              ],
              "AM": [
                "02"
              ],
              "CW": [
                "03"
              ],
              "RTTY": [
                "04"
              ],
              "FM": [
                "05"
              ],
              "WFM": [
                "06"
              ]
            }
          }
        }
      ],
      "restriction": "when_receiving"
    },
    "write_tx_mode": null,
    "write_ptt_off": null,
    "write_ptt_on": null
  }
}

Where to Contribute

SkyCAT GitHub

Submit a pull request adding IC-R7000.json to the Rigs folder:

  • URL: https://github.com/VE3NEA/SkyCAT
  • Fork the repo, add IC-R7000.json to the Rigs/ folder, open a pull request
  • Include this document’s notes in the PR description

SkyRoof Google Group

Alex VE3NEA (the developer) is very active and responsive. Post your findings and the working JSON:

hamlib Issue Report

The incorrect 52h address in hamlib’s R7000 model definition is worth flagging so future users are not misled:

Quick Setup Instructions

For anyone setting up IC-R7000 with SkyRoof for the first time:

  • Hardware: Connect R7000 to PC via CT-17 CI-V interface. Set rear panel REMOTE switch to ON.
  • SkyCAT: Download SkyCAT 1.6 from https://github.com/VE3NEA/SkyCAT/releases. Place IC-R7000.json in the Rigs/ folder.
  • Start daemon: skycatd.exe -m IC-R7000 -r COM4 -s 1200 -t 4532 (adjust COM port as needed)
  • SkyRoof settings: CAT Control > RX CAT: Host 127.0.0.1, Port 4532, Enabled True. Radio Type: Simplex. Delay: 500ms.
  • Verify: RX CAT dot in SkyRoof status bar should turn green. R7000 frequency display should step with Doppler correction during satellite pass.

Developed and tested by N1BAQ, FN41QO. May 2026. Verified working with SkyCAT 1.6 and SkyRoof 1.29.

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