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GNSS Positioning Simulator: What does it mean if the LCD displays an 'OVEN' message / PosApp reports 'Modulator Oven Cold'?

  • STR4720 / 4730 / 4750 / 4760 / 4780 / 4790
  • GSS7700 / 7735 / 7790 / 7800 / 7900
  • GSS8000
  • The OVEN warning is reported by the IF module fitted inside the simulator chassis.
  • Depending on the simulator model and its signal capability, there may be more than one IF module fitted.
    • As such, you may see OVEN 1, 2, 3 or 4 reported independently of each other.
  • The LCD will cycle through each OVEN warning as necessary.
  • Under normal circumstances the OVEN warning message is displayed on the simulator LCD when it is first powered and and the unit is warming up.
    • Typically this will only last for the first 2-3 minutes after power on.
  • But if the unit has been turned off for a prolonged period of time and/or has been stored in a cool / cold room before being turned on again, then the OVEN warning message can persist for longer
    • Perhaps 5-10 minutes
  • However, if OVEN warning message has not disappeared then this highlights a potential fault with the IF module
    • The simulator must have been turned on for a sufficient length of time - Spirent advise 30 minutes for a suitable 'warm-up' prior to use
    • The ambient temperature should be within the normal operating range, though a normal lab environment will be approximately 21oC


  1. The OVEN warning does not prevent you from running scenarios with the PosApp software
        - Though the accuracy of the RF signal 'may' be impaired, e.g. a higher than expected spurious signal at the carrier frequency.
  2. PosApp will record the OVEN warning message in it's message log display and in it's message log file in the format
        - BITE Info: Information: GSS8000 8025 Modulator 1 oven cold
  3. If you suspect a fault please contact Spirent Global Services
        a) Create a Service Request using the "Open a Service Request" link on the right hand side of the Knowledge Base screen
        b) Provide the model and serial number of the simulator displaying the fault
        c) Confirm you have reviewed this article and ensured the unit has been left to warm-up in a room with 'normal' ambient temperature conditions

Product : STR4790,STR4780,STR4760,STR4750,STR4730,GSS7790,GSS7735,GSS7700,GSS7800,GSS7900