AFS (Automatic Frequency Selection) allows TM4 units to shift their operating frequency slightly to avoid interference. This is especially important in environments with multiple radars operating nearby.

Overview of AFS Frequencies

Each TM4 unit is factory-calibrated to a specific frequency, which is printed on a sticker on the bottom of the unit. When you manually adjust the AFS setting, you are shifting that base frequency by 1 MHz per step.

If a unit is calibrated to:

• 10.510 GHz, setting AFS to +1 changes it to 10.511 GHz
• 24.106 GHz, setting AFS to +1 changes it to 24.107 GHz

Overlap of Frequencies

This means that two units with different base frequencies can still end up on the same frequency if their AFS settings overlap.

• Unit A: Calibrated to 10.510 GHz, AFS set to +2 → 10.512 GHz
• Unit B: Calibrated to 10.515 GHz, AFS set to –3 → 10.512 GHz
  → These two units will interfere with each other.

Below are the best practices for setting AFS manually:

• Always check the unit’s base frequency.
• Calculate the resulting frequency based on the AFS value.
• Ensure no two units in the same area share the same final frequency.