Calibrate the GPSDO frequency offset¶
Use this page to correct the frequency reference of your FLEX-8600 using the built-in calibration controls. Accurate frequency calibration reduces dial error across all bands.
Before you start¶
- AetherSDR must be connected to the radio. The RX tab in Radio Setup is only available when a radio connection is active.
- If a GPSDO is installed, the calibration controls are still available. Without a GPSDO, a yellow status message is shown instead of the green GPSDO confirmation.
Steps¶
- Open
Settings > Radio Setup.... - Click the RX tab.
- In Cal Frequency (MHz):, enter the frequency of a known-accurate reference signal.
- Click Start to begin the calibration sweep. The button label changes to Busy and a status message appears while the sweep runs. The Start button is disabled until the sweep completes or fails.
- When the sweep completes, review the measured offset shown in Freq Offset (ppb):.
- If you prefer to set the offset manually rather than using the sweep result, edit Freq Offset (ppb): directly.
What each control does¶
| Control | Kind | Description |
|---|---|---|
| Cal Frequency (MHz): | Spinbox | The reference frequency used during the calibration sweep. Set this to a known-accurate signal — for example, a broadcast standard-frequency station. The field must not be empty before clicking Start; if it is empty, a warning is shown and the sweep does not start. |
| Start | Push button | Initiates the calibration sweep at the frequency entered in Cal Frequency (MHz):. Before starting, AetherSDR resets the current frequency error to zero (freq_error_ppb=0) so the sweep begins from a clean baseline. The button is disabled and shows Busy while the sweep is in progress. |
| Freq Offset (ppb): | Spinbox | The frequency offset applied to the radio's reference oscillator, in parts per billion. Can be set by the sweep or entered manually. |
| 10 MHz Reference Source: | Combo box | Selects the oscillator reference source. Valid values: Auto | TCXO | GPSDO | External 10 MHz. Options shown depend on hardware installed and on the states reported by the radio at the time the tab is built. The combo is populated dynamically: TCXO and External 10 MHz entries appear whenever the radio reports their presence or when they match the current setting or active state; GPSDO appears when a GPSDO is detected or when the current setting or state is gpsdo. If the radio reports a source that is not yet in the list, it is added automatically. Lock status is displayed alongside the combo box and updates live (see Oscillator status label). |
| TX Follows Active Slice | Push button | TX follows the active slice. Mutually exclusive with Active Slice Follows TX. Disabled automatically during Split operation. |
| Active Slice Follows TX | Push button | Switches the active slice when TX moves externally (for example, from WSJT-X or CAT). Mutually exclusive with TX Follows Active Slice. |
| Voice / CW / Digital filter sharpness sliders | Slider | Sets filter sharpness (0 = lowest latency to 3 = sharpest) per mode. The slider is disabled when Auto is enabled for that mode. Commands sent as radio filter_sharpness <mode> level=<N>. |
| Auto (Voice / CW / Digital) | Toggle button | Enables automatic filter-level selection for that mode and disables the manual sharpness slider. Commands sent as radio filter_sharpness <mode> auto_level=1. |
| Connect / Disconnect (TGXL) | Push button | Opens or closes a direct TCP connection to the TGXL on port 9010. Saves the IP and port to TGXL_ManualIp and TGXL_ManualPort on connect so AetherSDR auto-reconnects on startup. Required to recover TUNE on firmware 4.2+. When connected, the TUNE button sends the native autotune command directly to the TGXL instead of the radio-side path broken in firmware 4.2. The TGXL drives radio PTT via its hardware interlock cable; no client-side keying is needed. If the IP field is empty and the radio has already discovered the TGXL, the discovered IP is pre-filled. |
| Connect / Disconnect (PGXL) | Push button | Opens or closes a direct TCP connection to the Power Genius XL (default port 9008). Saves the IP and port to PGXL_ManualIp and PGXL_ManualPort. |
| Connect / Disconnect (Antenna Genius) | Push button | Opens or closes a connection to the Antenna Genius (default port 9007). Saves the IP and port to AG_ManualIp and AG_ManualPort. The row is hidden from the Connected status if a ShackSwitch (rather than an Antenna Genius) is the connected device. |
| Connect / Disconnect (ShackSwitch) | Push button | Opens or closes a connection to a ShackSwitch antenna switch via the AG UDP/TCP protocol on port 9007. Saves the IP to SS_ManualIp and the port to SS_ControlPort. ShackSwitch is detected by the ShackSwitch field in the AG broadcast beacon. Auto-discovery via UDP also works without this row. The row is hidden from the Connected status if an Antenna Genius (non-ShackSwitch) is the connected device. |
| ⚙ Web UI (ShackSwitch) | Push button | Opens the ShackSwitch device's local web configuration interface in the system browser. Uses the beacon's webPort if greater than 1024, otherwise falls back to SS_WebPort or port 5000. |
| Select Installer... | Push button | Opens a file picker that accepts .msi (FlexRadio v4.2+ WiX installer), .exe (older self-extracting installer), or a pre-extracted .ssdr firmware file. The firmware stager auto-detects the format from the first 8 bytes (OLE/MSI magic vs PE/COFF MZ) and extracts the .ssdr without external tools. When an update is available, the status label instructs you to download the SmartSDR installer from flexradio.com and then click Select Installer... to stage it. Label changed from Browse .ssdr... in v0.9.3. |
| APD (tab) | Tab | External Adaptive Pre-Distortion sampler configuration — per-TX-antenna selection of the feedback sample port (INTERNAL / RX_A / RX_B / XVTA / XVTB) and an equalizer reset button. Tab is hidden unless the radio reports apd configurable=1. Only FLEX-8x00 series with SmartSDR 4.2.18+ firmware exposes this; 6000-series and pre-4.2.18 radios keep the tab invisible. |
| ANT1 / ANT2 / XVTA / XVTB sampler combos (APD) | Combo box | Selects the feedback path the radio uses to sample the outgoing RF for APD training for that TX antenna. Choose an external RX/XVTR input when driving an external linear amplifier. Options are populated live from the radio's apd sampler sub-object. Falls back to INTERNAL if the radio reports an unrecognised value. |
| Equalizer Reset (APD) | Push button | Sends apd reset to the radio, clearing all per-antenna APD training data so adaptation starts fresh. |
| Themes (tab) | Tab | UI customization tab — currently hosts the Slice Colors section. |
| Use Aether defaults / Custom colors | Radio button | Switches the slice color scheme between the built-in AetherSDR palette and a fully custom per-slice set. |
| Slice A–H color buttons | Push button | Click any lettered button (A–H) to open a color picker and assign a custom color for that slice. Changes are visible immediately in VFO widgets, panadapter overlays, and CAT channel badges. Buttons are disabled when Use Aether defaults is selected. Up to 8 slices supported. |
| Reset All to Defaults (Themes) | Push button | Resets all custom slice colors to the built-in AetherSDR palette. |
Oscillator status label¶
Starting with v0.9.7, the lock status label beside 10 MHz Reference Source: displays richer information than the previous plain <SOURCE> Locked / Unlocked text.
The label is built as follows:
- If the radio has not yet reported an oscillator state, the label reads Waiting for oscillator status in a neutral blue-grey colour.
- If the active state differs from the configured setting (for example, Auto is selected but the radio has chosen GPSDO), the label shows the transition:
Auto -> GPSDO. - If both the setting and the state are known and match, only the active source name is shown.
- Locked or Unlocked is always appended after the source name.
- If the source is External 10 MHz but the radio reports that no external signal is present, the label appends (not detected).
Colour coding:
| Colour | Meaning |
|---|---|
Green (#00c040) |
Oscillator is locked. |
Red (#c04040) |
Oscillator is unlocked. |
Blue-grey (#8aa8c0) |
Oscillator state not yet received from the radio. |
The label updates live as the radio reports state changes. No action is required to refresh it.
The External option in the combo box is now labelled External 10 MHz (changed from External in v0.9.7) to match the label used in the status text.
Calibration status messages¶
Starting with v0.9.2.1, a status label appears next to the Start button and updates throughout the sweep.
| Message | Colour | Meaning |
|---|---|---|
| Starting... | Blue-grey | The calibration command sequence has been sent to the radio. |
| Enter cal frequency | Amber | Cal Frequency (MHz): was empty when Start was clicked. Enter a frequency and try again. |
| Busy | — | Shown on the Start button itself while a sweep is in progress. |
GPSDO status banner¶
The banner at the top of the calibration group reflects whether a GPSDO is installed:
- Green banner — GPSDO is installed. Manual frequency offset calibration is still available.
- Amber banner — No GPSDO installed. Manual frequency offset calibration is available.
In v0.9.2.1 the green banner wording changed. Previously it read "GPSDO is installed. Frequency error correction is not required." It now reads "GPSDO installed. Manual frequency offset calibration available." This makes the behaviour consistent: the calibration controls are always shown regardless of GPSDO presence.
Firmware update workflow (v0.9.3)¶
In v0.9.3 the firmware update flow changed. AetherSDR no longer downloads and stages firmware automatically when an update is detected. Instead:
- Click Check for Update on the Radio tab. If an update is available, the status label displays the version number and instructs you to download the SmartSDR installer from flexradio.com.
- Download the installer from flexradio.com (
.msifor SmartSDR 4.2+,.exefor older releases). - Click Select Installer... (previously labelled Browse .ssdr...) and choose the downloaded file. AetherSDR accepts
.msi,.exe, or a pre-extracted.ssdrfile and stages the firmware automatically, detecting the format from the file header. - Once staging completes, click Upload Firmware to transfer the firmware to the radio.
The Check for Update button no longer relabels itself as a download trigger after detecting an available update.