GSM1900 and 802.11b intermodulation

Hi, we tested the RedBean (new version with improved filtering) together with a Quectel BG96 celluar
modem for simutaneous emissions according §15.209.
RedBean is operated at Channel 11 (2462 MHz) and the BG96 with GSM 1900 on 1880 MHz. Now there is
a emission at 582 MHz (2462 MHz - 1880 MHz = 582 MHz) looking exactly like a 802.11b signal 3.5 dB
beyond the limit. Any suggestions?
Plots are available, but uploading into the ticket failed.

Hi wwadepohl,
You can follow these steps to check:

  1. Check different WIFI and LTE channels.
  2. Check whether filter or switch is used on WIFI and LTE RF trace, and bypass them if used.
  3. Change the WIFI antenna and LTE antenna and retest again.
  4. Whether to add a shield cover to the WIFI area, and whether the WIFI antenna and LTE antenna are too close.
  5. Try to reduce WIFI and LTE TX power.

Thanks !