WiFI Signal strength issue in P1 module

Some of my P1 module based board disconnect from WiFi signal when away from 5 meter and some board easily connected with wifi router up to 15m.

What could be the reason?

Is it a customized board?

yes, it is customized board.

Well, the antenna is surrounded by the ground plane which affects antenna performance.

You can do a test with an external antenna and it should connect well.

The solution is to:

  1. align the antenna to the edge of the board so that there’s no ground loop
  2. ensure that there’s not ground plane underneath the antenna region

Thanks for the input :slight_smile:

There is no ground plane or any copper underneath the antenna region but yes, antenna is not aligned to the edge of the board.
And, why there is difference while all boards have same circuit & design but different behavious in terms of WiFi signal?

That large DHT temperature sensor on the right-hand board is definitely in the way of WiFi signals. Have you considered moving that?

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Hi @bko,

I considered DHT sensor & other components too (See in pics).
I tested without DHT but same behavior.

The ground pour around the P1 may be creating a ground loop, causing interference. Another reason to have the P1 on the edge.

Use WiFi.RSSI(); to get some readings for the signal strength.

Try the board with minimal or fully tested code e.g Tinker and see if problem remains, it is more than possible to upset the WiFi connection if you are keeping the processor busy doing something else.

Buy something like https://www.sparkfun.com/products/11320 (similar adhesive antenna can be had for ~$1 in bulk) and try it with that instead, if performance improves you can safely blame the board layout.

Fire up your phone/laptop and use a WiFi Analyzer app to establish just how congested the 2.4 Ghz band is and if you are using the best channel available. It really only takes 3 powerful high bandwidth routers nearby to really compromise performance.

Consider the proximity (and number) of other RF devices such as baby monitors, smart meters, DECT phones and bluetooth peripherals.

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Hi @peekay123

yup, I also think, it may be the reason but we made 50 units already. It is the real problem.
Please give idea, how can we solve this problem in these existing boards?

Hi @Viscacha

Thank you for detailed answer.
I will try all that you mentioned here.

I would look at external antenna, cheapish simple, potentially better than the on-board one.


Do I need to change the firmware code or any other kind of changes in hardware if we add external antenna (u.FL connector)?

just a little change https://docs.particle.io/reference/firmware/photon/#selectantenna-antenna-


Thank you so much :slight_smile: I understood most of the things now.

Just check below link and please tell me that whether this u.FL connector https://www.aliexpress.com/item/20PCS-Lot-2-4G-IPEX-Male-connetor-Cable-Single-head-Adapter-1-13-15CM/32644017235.html
is good choice or not?

thats just a connector on a wire…
I was thinking of something like https://www.aliexpress.com/item/1-Pair-Universal-Laptop-Mini-PCI-E-Wireless-Wifi-Internal-Antenna-ipx-ipex-u-fl-antenna/32679923839.html?spm=2114.01010208.8.4.exTjeP
The kind of thing you would find coiled inside a laptop.

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Thank you for the help.

Tell you whether it works or not.
Thanks again!

Hi @Viscacha

Today I received the antenna that you suggested.

Works like a charm :slight_smile:

Thanks again!

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Excellent news.