Icom IC-7300 setup for pictures and digital modes
One USB lead does everything on an IC-7300 — audio in, audio out and rig control — which makes it one of the easiest radios to get on digital modes. Almost every problem people hit comes down to three settings: the mode, the USB MOD level, and how PTT is keyed.
1. The cable and the mode
- A single USB-B lead from the radio to the computer. The IC-7300 appears as a sound card and a serial port — no interface box required.
- Set the mode to USB-D, not plain USB. The data modes take transmit audio from the USB codec and bypass the microphone and speech processor.
- In plain USB the radio takes audio from the microphone. It will key up perfectly and transmit nothing — the single most common IC-7300 digital-modes fault.
2. Levels
- Menu → Set → Connectors → USB MOD Level. Start around 30–50%.
- Set it by ALC, not by ear: raise the level until ALC just begins to register, then back off. The meter should barely move.
- In Open Signal the TX LEVEL slider is the master before the radio ever sees the audio. Start at about 50% and let the station log tell you what the peak actually was.
- A swinging ALC bar means distortion, and distortion on a picture mode means a signal that is both wider and harder to decode. Quieter is better.
3. PTT — three ways, all fine
The IC-7300 will key from data-mode VOX, from a serial RTS/DTR line, or over CI-V on the cable that is already carrying rig control. Pick whichever suits — none is wrong.
- VOX is the least to configure: turn data-mode VOX on and the radio keys itself when audio arrives.
- CI-V is the tidiest, because it needs nothing beyond the USB lead you already have.
One caution about CAT keying on any Icom: if the radio misses the “stop transmitting” command, a program that assumes the command worked will show “receiving” while the rig is still keyed. How Open Signal handles that — it waits for confirmation, retries the release and reads back the radio’s actual state.
4. CI-V settings
- CI-V address defaults to
94hon an IC-7300. - CI-V Baud Rate defaults to 19200. If rig control is flaky, set a fixed rate rather than leaving it on Auto.
- Leave CI-V Transceive off unless something else on the bus needs it — it echoes every frequency change and can confuse a program that is not expecting the traffic.
With CAT connected, Open Signal follows the VFO on its own, so the frequency written into your log is the one you actually transmitted on.
IC-7300 questions
Do I need a sound-card interface for an IC-7300?
No. The IC-7300 has a USB sound card and CI-V built in, so a single USB-B lead carries transmit audio, receive audio and rig control. An external interface such as a Digirig or SignaLink adds galvanic isolation, which is worth having if you get RF in the shack, but it is not needed to get on the air.
Which mode should the radio be in?
USB-D (data USB) rather than plain USB. In the data modes the radio takes transmit audio from the USB codec and bypasses the microphone and the speech processor. Plain USB takes audio from the microphone, so the rig will key up and transmit nothing.
What should USB MOD level be set to?
Start around 30–50% and set it by ALC, not by ear. In Menu → Set → Connectors → USB MOD Level, raise it until ALC just begins to show and then back off. On an IC-7300 the meter should barely twitch — if the ALC bar is swinging, the signal is being distorted and will be splattering either side of you.
How do I set PTT — CI-V, RTS, or VOX?
Any of the three work. Data-mode VOX is the simplest and needs no configuration beyond turning it on. CI-V keying is the tidiest because the same cable already carries rig control. If you use CI-V, be aware a missed release command can leave a radio transmitting — Open Signal waits for the radio to confirm, retries the release and reads back what the rig is actually doing rather than assuming.
What CI-V address and baud rate does an IC-7300 use?
The default CI-V address is 94h and the default baud rate is 19200. Both are in Menu → Set → Connectors → CI-V. If rig control is unreliable, set CI-V Baud Rate to a fixed value rather than Auto, and leave CI-V Transceive off unless something else on the bus needs it.
Why does my IC-7300 key up but send no audio?
Almost always the mode: the radio is in USB rather than USB-D, so transmit audio is being taken from the microphone. Check the mode first, then that USB MOD Level is not at zero, then that the computer is sending audio to the radio's USB codec rather than to its own speakers.
More about Open Signal
Radio connected? Send a picture
Receiving is free forever and needs no licence key. Point Open Signal at the IC-7300's codec, tune to an active frequency, and see what arrives.