How to Configure NTP Time Sources

Applies to: FLEX-8000 Series and Aurora radios
License: SmartSDR Basic (v4.3)
Clients: Configured from SmartSDR for Windows only

Overview

SmartSDR for Windows includes an NTP tab in Radio Setup, where you configure the NTP (Network Time Protocol) sources the radio uses to synchronize its clock.

• Up to 10 sources can be configured.
• The radio must have network access to reach its sources.
• The NTP tab does not appear for radios that do not support the feature.

The radio ships with one source already configured: a pool named default-pool pointing at the Debian NTP pool, 2.debian.pool.ntp.org. The radio re-creates this source on any start-up where no sources are configured, so a radio is never left permanently without a time source.

Viewing NTP Sources

1. In SmartSDR for Windows, navigate to Settings > Radio Setup.
2. Select the NTP tab.

The NTP Time Sources list shows each configured source:

Selecting a row shows a Selected source panel below the list with live detail:

A dash in these fields means the radio has no current data for the source, normally because the source is disabled or was just added. The Status column is blank in the same situation.

Note: Status and the detail panel refresh on a 30-second cycle. A newly added source may show a blank Status, or read Unreachable, for a poll or two before it settles.

Adding an NTP Source

1. On the NTP tab, click Add. The Add NTP Source dialog opens.
2. Enter a Name (required). The name:
   • May contain only letters, digits, and hyphens
   • May not start or end with a hyphen
   • May be up to 64 characters
   • Must be unique on the radio and cannot be changed after the source is created
3. Enter the Address (required): a hostname or IP address of up to 253 characters, using only letters, digits, and the characters . : - _ %.
4. Select the Type:
   • server — A single NTP server.
   • pool — A DNS name that resolves to a set of servers, several of which the radio uses.
   • peer — Another NTP peer, which exchanges time with the radio in both directions.
5. (Optional) Enter a Description of up to 62 characters, using letters, digits, spaces, and the characters . _ -.
6. (Optional) Select Prefer this source. The radio favors a preferred source over the others while it is reachable. If several sources are preferred, the radio favors whichever preferred sources are reachable.
7. Click OK.

Editing an NTP Source

1. Select a source and click Edit, or double-click the row.
2. Change the Address, Type, Description, or Prefer setting as needed. (The Name cannot be changed.)
3. Click OK.

If the radio rejects the change, the source is restored to its previous settings, and SmartSDR reports the failure.

Tip: You can also toggle Prefer directly in the list by clicking the check box in the Prefer column.

Removing an NTP Source

1. Select a source.
2. Click Remove.

Any source can be removed, including the shipped default-pool.

• If the source is the radio’s only enabled time source, SmartSDR warns you that the radio clock will free-run until a source is added or re-enabled.
• If the radio is left with no sources at all, it stays that way until the next restart, when default-pool is automatically created again.

Sources persist across reboots.

Status Values

NTP Sources on Maestro and M-Models

NTP sources are configured from SmartSDR for Windows only. There is no NTP configuration in Maestro or on M-Model front panels. Because sources are stored on the radio itself, a radio configured once keeps its sources however it is later operated.

NTP and a GPSDO

NTP sources and the GPSDO are independent, and you do not choose between them in SmartSDR. The radio’s time service makes that choice and prefers the GPSDO. When a GPSDO is installed and delivering time, it disciplines the radio clock, and the NTP sources act as a fallback when GPS time is unavailable.

• The GPSDO does not appear in the NTP Time Sources list, which shows only network sources.
• On a radio running on GPS time, it is normal to see no source marked In Use, even though the radio clock is correct and disciplined.
• Configuring NTP sources does not change GPS operation, and installing a GPSDO does not require any change to the NTP configuration.
• The GPS tab in Radio Setup is unrelated to this list.

Troubleshooting