Wifi and GNSS modules coexistence on the same PCB, how bad it is

IoT Modules GNSS Module
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Hi all,

I’m designing a GNSS board around a Quectel LC29H/LC29HEA (dual-band RTK).

I need a small MCU for configuration only (web UI / BLE provisioning). The ESP32 is attractive because it gives me Wi-Fi/BLE + embedded web server easily.

Important point:
The ESP32 would be used only during configuration. In normal operation:

  • No Wi-Fi traffic
  • No BLE traffic
  • Radio disabled (or deep sleep if possible)

GNSS runs continuously and performance (C/N0, RTK stability, heading) is critical.

Questions:

  1. In practice, does having an ESP32 on the same PCB significantly degrade GNSS sensitivity, even if RF is disabled after setup?
  2. When Wi-Fi/BLE is disabled, are there still internal clocks or spurs that commonly affect GNSS?
  3. Is shielding + good layout generally sufficient, or is separating the RF MCU onto another PCB the safer choice?
  4. Any specific clock or DC/DC frequency ranges to avoid near GNSS L1/L2?

Antenna will likely be an active patch via coax (U.FL).
4-layer PCB with solid ground plane.

Looking for real integration feedback.

Thanks.

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Hi @mkergo35

Please refer below for the answer, is recommended to drop us an email so i can fully understand your application and ensure smooth integration for your product
Email: yong.huang@quectel.com

In practice, does having an ESP32 on the same PCB significantly degrade GNSS sensitivity, even if RF is disabled after setup?

Answer:
As long as the GNSS module and ESP32 are placed far apart — ideally at opposite ends of the PCB — the impact on GNSS performance is minimal.
We also recommend adding a SAW filter in front of the RF_IN port to further suppress out‑of‑band interference and improve overall signal quality.

When Wi-Fi/BLE is disabled, are there still internal clocks or spurs that commonly affect GNSS?

Could you please provide more details about your concern?

Is shielding + good layout generally sufficient, or is separating the RF MCU onto another PCB the safer choice?

Answer:
Following the design guidelines we provide is generally sufficient for achieving good RF performance.
You are welcome to send us your PCB layout and schematic for review via email. We can help verify that your design meets best‑practice GNSS requirements.

Any specific clock or DC/DC frequency ranges to avoid near GNSS L1/L2?

Answer:
Please avoid harmonic frequencies that fall within the GNSS bands:

  • 1164–1189 MHz (E5/L5/L2 band)
  • 1559–1606 MHz (L1/B1/E1 band)

You can verify this using the reference formula:

Harmonic frequency = N (harmonic number) × Clock frequency

Is better we can communicate in email for this project

best regards,