Set the TX audio high-cut frequency¶
Use the Phone applet to raise or lower the upper boundary of the TX audio passband. Narrowing the high-cut reduces transmitted bandwidth; raising it passes more high-frequency audio content.
Before you start¶
- AetherSDR must be connected to the radio. The Phone applet requires an active radio connection.
- The radio must be in a phone mode (SSB, AM, or similar) for TX filter changes to have audible effect.
Steps¶
- If the Phone applet is not visible, click the PHNE tray button in the right sidebar to show it.
- Locate the High Cut column on the right side of the TX filter section, below the DEXP row.
- Click > to increase the high-cut frequency to the next multiple of 50 Hz, or click < to decrease it to the next lower multiple of 50 Hz. You can also scroll the mouse wheel over the value display to step in either direction.
- Read the current value in the numeric display between the < and > buttons.
What each control does¶
| Control | Description | Default |
|---|---|---|
High Cut < |
Decreases the TX filter high-cut frequency to the next lower multiple of 50 Hz. | — |
High Cut > |
Increases the TX filter high-cut frequency to the next higher multiple of 50 Hz. | — |
| High Cut value display | Shows the current high-cut frequency in Hz. | 3300 Hz |
The high-cut frequency cannot be set below the current low-cut frequency plus 50 Hz. For example, if low-cut is set to 100 Hz, the minimum high-cut value is 150 Hz.
How stepping works¶
The < and > buttons snap the value to the nearest multiple of 50 Hz in the chosen direction, rather than adding or subtracting a fixed 50 Hz from the current value. For example, if the current high-cut is 3275 Hz, clicking > sets it to 3300 Hz and clicking < sets it to 3250 Hz. This behaviour applies equally to the Low Cut controls.
The radio accepts any integer Hz value, so if the current value is already an exact multiple of 50 Hz the result is the same as a plain 50 Hz step.
Tips¶
- For larger changes, use the scroll wheel with rapid movement rather than repeated button clicks.
- A typical SSB passband uses a low-cut of 50 Hz and a high-cut of 3300 Hz. Reducing high-cut to around 2700–2800 Hz can improve intelligibility in noisy conditions by removing high-frequency hiss.
- The high-cut setting is not persisted by AetherSDR's local settings — it is sent directly to the radio and stored in the radio's active profile.