External Antenna

General
1

Hi photon fellows:

I need to install a Photon in a place with almost no WiFi signal.
My idea is to connect to the photon an external antenna (4 meters of cable aprox). Is it possible?. Is there an standard connector for an external antenna in the microcontroller?

On the other hand, if I connect an external antenna, is it neccesary to specify it in the program code?

thank you in advance.

Marcelo

2

Yes, the uFL connector on the Photon is an industry standard.
But no, you can’t just connect any old cable as antenna, you need an antenna that’s suitable for 2.4GHz WiFi.
The command to switch antenna is documented here
https://docs.particle.io/reference/firmware/photon/#selectantenna-

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3

ScruffR:
Thank you so much for your answer.

I found an adapter cable from RP-SMA to uFL. from Adafruit.
product view

Now, my questions are:

  1. The uFL connector is mechanical enchase into the photon connector of it must be weld on it?
  2. If I use an external antenna. Is there something to unweld on photon (i.e. the internal antenna) or by code I just select which antenna to use
  3. The anntena cable can have 10 meters long? (coaxil cable?)

thank you
marcelo

4

The uFL connector is a tight press-fit connector. No soldering is needed.

You select the external antenna in software on a Photon and the setting is “sticky” so that the Photon will try to use the external antenna from that time on.

An antenna cable length of 10 meters is probably too long unless the antenna is an “active” antenna that has a built-in amplifier (which requires power to the antenna).

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5

Thanks so much bko.

You said:

You select the external antenna in software on a Photon and the setting is “sticky” so that the Photon will try to use the external antenna from that time on.

It means that if I put in my program:

STARTUP(WiFi.selectAntenna(ANT_EXTERNAL));

  1. After that, not matter if I upload another program from particle portal (it means load and reset the photon) continue to receive from external antenna?

  2. On the post: Add external antenna to chip-antenna core? you found the following question and answer.

if I remove the L1 inductor, does that disable the chip antenna? I’d like to be able to use either the uFL or chip antenna

You can’t use both, sorry. The antenna matching circuit only supports one or the other.

The point is:

  1. First I run the program (with internal antenna wifi conn), and the program set External Antenna
  2. I install my photon in a place that has no signal for internal antenna.
  3. Perhaps, I have to load a new version of program to it. (it implies photon reset). I need, when the photon try to connecto to wifi use the external antenna.

Thank you very much,
marcelo

6

That refers to the Spark Core which was available as either chip or uFL version, but Photons come with support for both.

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7

What is the reason for the proposed 4m or 10 meter long antenna cable? Have you used another device such as a cellphone and observed significant differences in signal strength between the installation location and proposed antenna location?

Also take a look at getting the signal strength (see https://docs.particle.io/reference/firmware/photon/#rssi- ) so if it obtains a connection you can evaluate changes in signal strength as you make adaptations.

Not sure about your situation but the other alternative is use a WiFi extender to provide better signal at the location.