Skip to main content

Control Tab

SDDC LabAbout 2 min

Control Tab

The Control tab manages receiver operation, access, capacity, and SNR measurement policy.

Control page with Airband clock settings
Control page with Airband clock settings

Service Lifecycle

  • Restart server restarts the receiver application without rebooting Linux.
  • Reboot device restarts Linux and all receiver services.

Both actions require confirmation.

Radio Configuration

  • HF frequency range selects the 32 MHz or 64 MHz FPGA range used for HF reception.
  • Receiver bandwidth selects 12, 24, or 36 kHz.
  • User-selectable band mode exposes the Air/HF selector to receiver users.
  • Airband ADC clock appears only when Air mode is enabled.

These settings require a server restart. For ordinary browser listening, 12 kHz receiver bandwidth is recommended. Some extensions may not support 36 kHz correctly.

In Air mode, Web-888 switches to the VHF input and uses oversampling for Airband and 2 m reception.

Airband ADC Clock

  • 98.304 MHz (recommended) supports 12 and 24 kHz receiver bandwidths and covers 98.304-147.456 MHz. It provides the best rejection of aliases from the 88-108 MHz FM broadcast band.
  • 110.592 MHz supports 12, 24, and 36 kHz receiver bandwidths and covers 110.592-165.888 MHz. Frequencies from 108 to 110.592 MHz are unavailable with this profile.

When 36 kHz receiver bandwidth is selected, Web-888 forces the effective clock to 110.592 MHz and disables the clock selector. Restart only the Web-888 server during iterative configuration; a complete operating-system reboot is not required.

Listener Availability

  • Receiver connections allows or rejects new listener connections.
  • Waterfall channel assignment selects shared or exclusive waterfall allocation.
  • Waterfall and spectrum can disable visual data streams to reduce outbound bandwidth.
  • External application capacity limits simultaneous channels used by non-native clients such as kiwirecorder and overrides the matching TDoA setting.

Availability changes marked by the restart indicator take effect after a server restart.

Session Management

Kick all users disconnects every active receiver session. Two message fields control what listeners see:

  • the message shown when receiver access is disabled
  • the message shown after users are disconnected

Each field has an HTML preview.

Connection Time Limits

  • Inactivity limit disconnects inactive clients after the configured number of minutes.
  • Per-IP daily limit limits total daily use by a client IP.
  • Time-limit exemption password bypasses both limits and can be supplied in a receiver URL as /?password.

Use 0 for no limit. Local-network connections are exempt.

Receiver Capacity

  • Audio campers per receiver channel controls how many listeners may monitor an occupied channel. Reduce it if audio camping causes receiver performance problems.
  • Allow non-native connections to preempt autorun processes lets external clients take channels assigned to preemptible autorun jobs.

These settings require a server restart.

SNR Monitoring

Automatic measurement interval can be disabled or set to hourly, 4 hours, 6 hours, or 24 hours. Results are published at:

http://web-888.local:8073/snr

Enable Timestamp SNR measurements with local time when local timestamps are preferred. Measure SNR now starts an immediate measurement.