Skip to content

Phone applet controls

The Phone applet provides voice transmit controls for AM carrier level, VOX settings, downward expander (noise gate) controls, and TX filter low-cut/high-cut frequency setters.

Voice-Operated Transmit (VOX)

VOX Enable

Click VOX to toggle voice-operated transmit on or off. When enabled, the radio will automatically begin transmitting when audio from the microphone exceeds the threshold set by the VOX level slider.

VOX level

Set the VOX activation threshold by dragging the VOX level slider. The slider range is 0 to 100. Higher values require louder audio to trigger transmit. The slider displays the value as a percentage (e.g., "48%") while dragging.

Delay

Set the VOX hang time by dragging the Delay slider. The slider range is 0 to 100. This controls how long the radio remains in transmit mode after audio stops before returning to receive.

AM Carrier Level

Drag the AM Carrier slider to adjust the AM carrier power level. The slider range is 0 to 100. The slider displays the value as a percentage (e.g., "48%") while dragging. The current value is shown as a numeric label next to the slider.

Downward Expander (DEXP)

DEXP Enable

Click DEXP to toggle the downward expander (noise gate) on or off.

Note: This control is non-functional on firmware v1.4.0.0 — the radio returns error 0x5000002D.

DEXP threshold

Set the DEXP gate threshold by dragging the DEXP threshold slider. The slider range is 0 to 100. The slider displays the value as a percentage while dragging. This setting is persisted in AetherSDR's local settings under DexpLevel. The DEXP toggle state is persisted under DexpEnabled.

Note: This control has the same firmware limitation as the DEXP toggle on v1.4.0.0.

TX Filter Low Cut

Adjust the TX filter low-cut frequency using the Low Cut < / > field. The default value is 50 Hz. The range is 0 to (high_cut − 50) Hz, stepping in 50 Hz increments.

TX Filter High Cut

Adjust the TX filter high-cut frequency using the High Cut < / > field. The default value is 3300 Hz. The range is (low_cut + 50) to 10000 Hz, stepping in 50 Hz increments.

Adjusting TX filter frequencies

  1. Click < to decrease the frequency to the next lower multiple of 50 Hz.
  2. Click > to increase the frequency to the next higher multiple of 50 Hz.
  3. Scroll the mouse wheel over the value display to step in either direction.
  4. Double-click the value display to type an exact Hz value. The typed value is honored on radios that accept it, while the radio's own readback is preserved elsewhere (issues #3627, #5064).

Step behaviour and direct entry

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.

Typed values are handled differently from steps:

  • A typed number is treated as a request for that exact value. Out-of-range values or values not on the radio's supported step grid are rejected, and the previous value is restored.
  • The step buttons clamp to the nearest valid value within the allowed range, stopping at the bound if it is reached.

When stepping, if the radio's backend publishes a discrete set of supported frequencies (an edge list), the buttons step to the next value in that list rather than to a multiple of 50 Hz. Otherwise, stepping snaps to multiples of 50 Hz.

The table below shows the difference:

Action Behaviour
Click < Moves to the next lower supported frequency. Clamps to the lower bound.
Click > Moves to the next higher supported frequency. Clamps to the upper bound.
Type a value Requests that exact frequency. Rejects values outside the valid range or not on the radio's supported grid.

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. Similarly, the low-cut frequency cannot be set above the current high-cut frequency minus 50 Hz.

What each control does

Control Description Default Setting Key
AM Carrier Sets AM carrier power level (0-100). — None
VOX Toggles voice-operated transmit on/off. — None
VOX level Sets VOX activation threshold (0-100). — None
Delay Sets VOX hang time before returning to receive (0-100). — None
DEXP Toggles downward expander (noise gate) on/off. — DexpEnabled
DEXP threshold Sets DEXP gate threshold (0-100). Persisted in DexpLevel. 0 DexpLevel
Low Cut < / > Adjusts TX filter low-cut frequency (0 to high_cut−50 Hz, step 50 Hz). 50 Hz None
High Cut < / > Adjusts TX filter high-cut frequency (low_cut+50 to 10000 Hz, step 50 Hz). 3300 Hz None

Theme support

The Phone applet uses theme-aware colors for all UI elements. Labels, sliders, and buttons adapt to the active theme. The applet container applies the applet/phone theme style, and all previously hardcoded color values have been replaced with themed equivalents. This ensures consistent appearance across light and dark themes.

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 low-cut and high-cut settings are not persisted by AetherSDR's local settings — they are sent directly to the radio and stored in the radio's active profile.

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

  1. If the Phone applet is not visible, click the PHNE tray button in the right sidebar to show it.
  2. Locate the High Cut column on the right side of the TX filter section, below the DEXP row.
  3. Do one of the following:
  4. Click > to increase the high-cut frequency to the next supported value, or click < to decrease it.
  5. Scroll the mouse wheel over the value display to step in either direction.
  6. Double-click the value display and type an exact Hz value.
  7. 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 supported value. —
High Cut > Increases the TX filter high-cut frequency to the next higher supported value. —
High Cut value display Shows the current high-cut frequency in Hz. Double-click to type an exact value. 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 next supported frequency in the chosen direction. On radios where the backend publishes a discrete list of supported frequencies, the buttons step through that list. Otherwise, they snap to the nearest multiple of 50 Hz. For example, on a continuous radio with a current high-cut of 3275 Hz, clicking > sets it to 3300 Hz and clicking < sets it to 3250 Hz. This behaviour applies equally to the Low Cut controls.

If the current value is already an exact supported value, the result is the same as a plain single-step movement.

Direct numeric entry

Double-click the value display to type an exact Hz value.

  • Valid values are those within the range from the current low-cut plus 50 Hz up to the radio's maximum supported high-cut, and on the radio's supported frequency grid.
  • Out-of-range or unsupported values are rejected, and the previous value is restored.
  • A typed value is treated as a request for that exact frequency, not a step, so it is not clamped to the nearest supported value — it is either accepted as-is or rejected.

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.

Set the TX audio low-cut frequency

Use the Phone applet to raise or lower the lower boundary of the TX audio passband. Raising the low-cut removes low-frequency rumble and sub-audio content from the transmitted signal; lowering it passes more low-frequency audio.

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

  1. If the Phone applet is not visible, click the PHNE tray button in the right sidebar to show it.
  2. Locate the Low Cut column on the left side of the TX filter section, below the DEXP row.
  3. Do one of the following:
  4. Click > to increase the low-cut frequency to the next supported value, or click < to decrease it.
  5. Scroll the mouse wheel over the value display to step in either direction.
  6. Double-click the value display and type an exact Hz value.
  7. Read the current value in the numeric display between the < and > buttons.

What each control does

Control Description Default
Low Cut < Decreases the TX filter low-cut frequency to the next lower supported value. —
Low Cut > Increases the TX filter low-cut frequency to the next higher supported value. —
Low Cut value display Shows the current low-cut frequency in Hz. Double-click to type an exact value. 50 Hz

The low-cut frequency cannot be set above the current high-cut frequency minus 50 Hz. For example, if high-cut is set to 3300 Hz, the maximum low-cut value is 3250 Hz.

How stepping works

The < and > buttons snap the value to the next supported frequency in the chosen direction. On radios where the backend publishes a discrete list of supported frequencies, the buttons step through that list. Otherwise, they snap to the nearest multiple of 50 Hz. For example, on a continuous radio with a current low-cut of 87 Hz, clicking > sets it to 100 Hz and clicking < sets it to 50 Hz. This behaviour applies equally to the High Cut controls.

If the current value is already an exact supported value, the result is the same as a plain single-step movement.

Direct numeric entry

Double-click the value display to type an exact Hz value.

  • Valid values are those within the range from the radio's minimum supported low-cut up to the current high-cut minus 50 Hz, and on the radio's supported frequency grid.
  • Out-of-range or unsupported values are rejected, and the previous value is restored.
  • A typed value is treated as a request for that exact frequency, not a step, so it is not clamped to the nearest supported value — it is either accepted as-is or rejected.

When you type a low-cut value that is very high, the radio's high-cut is not dragged upward to maintain the 50 Hz minimum separation. Instead

⚡ Athena AetherSDR Assistant
Hi! I'm Athena, the AetherSDR AI assistant. Ask me anything about installation, configuration, or troubleshooting.