Particle, have you done an in-depth analysis of the differences in signal strength between internal and external antennas, and between photon and argon? I’m really curious if there are hard numbers around these.
Thx!
There are no measured numbers yet.
Note the Argon does not have a built-in Wi-Fi antenna - it always uses an external Wi-Fi antenna (included) so the Wi-Fi performance will likely be better than the chip antenna on the Photon.
It’d be great if you guys could create this analysis.
In the meanwhile, couple more questions: is it thought that the rigid antenna will provide higher strength than the flex antenna?
Can it be assumed that an argon and a photon will have the same signal strength if they have the same external antenna? Or is it possible that one or the other could still have a stronger signal because of its internals?
I don’t think it’s safe to assume any equivalence between the signal strength of the Argon and Photon for Wi-Fi. They’re using completely different chipsets and RF hardware.
I believe this is the antenna shipping with the Argon: RFsister AN2402.0012.
http://download.rfsister.com/Antenna/AN2402.0012.pdf
It’s a non-flexible PCB antenna but it’s tiny. The length is shorter than the Argon so it should not have much of an effect on enclosure size.
@johnwest80 We use an external antenna all the time on photons and also enable the external antenna only in setup(). The external antenna will improve signal strength by 3-4dB which in real money is double. It has definitely been worth it for the devices deployed and generally stopped the connection loss that can happen. WiFi signal is absorbed by thing which move around (people) and you need the best antenna. Not sure what you mean by rigid and flex antenna - I use a TE connectivity WiFi antenna which is on a PCB with a short tail to a uFL connector.
When I say rigid vs flex, i’m just thinking of the two antennas that particle themselves sells.
What is the antenna you are using?
TE connectivity WiFi antenna with a 15cm lead and a uFL connector - a search on RS Components will give you something like this Mfr. Part No.2118309-1https://uk.rs-online.com/web/p/wifi-antennas/1249420/ - you may be able to find cheaper versions of the same.
Totally showing my ignorance here, but is there a maximum dbi antenna that the photon can support? Maybe an antenna requires a certain voltage or something? For example, here’s a 5dbi antenna that has a u.fl connector? Would it work on the photon (and, by association, the argon)?
My biggest concern with building a product around the particle devices is wifi issues. Knowing what my limitations are around external antennas will be very helpful. And if there’s a good article or doc on this already, please point me to it so I can teach myself to fish :).
John
dBi is the gain of the antenna (basically) which is a relative measurement. The photon wouldn’t care about that I’m pretty sure.
Not sure it helps, but I’ve used this one successfully: https://au.element14.com/siretta/delta15-smam-ra-rp-11/stubby-antenna-2-4-2-5ghz-sma/dp/2717669
If you’re doing product design, you may wish to enlist the assistance of an engineer who is accustomed to designing RF networks and with the device certification process. If you choose an antenna other than what has been pre-certified with the module, you will need to submit your device for testing as an intentional radiator. Additionally, you’ll need to have your device testing for unintentional radiation (which virtually all electronic devices with clocks need to undergo).
What you’re specifically interested is the output power of the device in dBm, which is a decibel referenced to one milliwatt. The antenna you use will create gain (positive, negative, or even zero) as it radiates the signal. The antenna typically will “concentrate” the signal with gain relative to an isotropic radiator (theoretical point source radiator) and this number is the dBi value which you’ll add to the dBm, and you’ll end up with an output power referenced in EIRP, which which is the equivalent isotropic radiated power. The addition of a higher gain antenna can increase the intensity of the radiated signal, but with the consequence of the propagation of the signal becoming more directional, i.e. there will be more power in the direction of propagation, but less total spatial coverage at the peak power.
You will then need to ensure that your device is radiating within the limits set by the FCC by comparing your EIRP to the FCC limits. The Photon’s output is not listed on the data sheet aside from “ask us.” The Argon’s power output is 8dBm, which is very modest. I’m assuming that the Photon has a comparable output power.
Anyway, the end goal is to create a link budget for your application, so doing some research on RF link budget calculations and analysis will be very helpful in your application.
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