ADS-B + Wifi = Interference?


#1

I recently switched my piaware setup, (Pi 2 + Orange FlightAware Pro) from using ethernet to wifi. Its in exactly the same place. The only other difference being FlightAware is now on a short 1ft USB extender cable ( it was covering all the USB ports) so that i can plug in a usb wifi.

I’ve noticed my # of aircraft drop down to about 25% of my usual total.

Can the wifi be interfering with the reception? I can provide pictures of the setup if needed.

Some information:

Setup is indoors, sitting on the window sill.

Thanks!


#2

wifi interference is possible - but also the usb cable could be the reason for this behavior. so as a first and simple step plug the flightaware-dongle directly into the pi and see if that helps.


#3

It’s too bad the FA dongles don’t come with a shielded case.


#4

to be honest i personally never saw the smallest advantage at my site with the shielded dongles. never had wifi or other interferences. maybe this can occur in different noisier locations …


#5

Interesting…


#6

yep - i have two pi2 running over one antenna and they are within 1% tolerance. i tried several fancy shielded sdr-dongles, wifi-dongles in the nearby usb-port, raspi zero w with integrated wifi etc. but never saw the slightest problem. that’s why i up today stick with my 10$ generic chinese plastic dongles :slight_smile:


#7

I don’t think they were any reports on the RPi built in wifi (Raspberry pi 3) causing interference.
We did have some reports of wifi dongles causing interference with the RTL dongles.
I tried all the wifi dongles I could find in the FA office and couldn’t reproduce the problem.

TomMuc is also right about shielding not helping ADSB signal detection. Shielding does lower noise but it doesn’t increase the range or number of planes seen or message rates.

The user that did report the wifi dongle interference did fix the problem with a USB extension cable.
I guess you might just have to figure out how to orient the parts to not interfere with each other?

Also, do you happen to have the make/model of the wifi dongle?


#8

Hi Everyone,

Sorry for being MIA. But I did do some diagnostics.

I tried it with just the USB extender on the FA, and with ethernet = No change.

Removing the USB extender and going to ethernet ( basically old config) = back to normal

I tried readjusting to have the FA direct to the Pi, and the wifi direct as well = Wifi not being recognized.

I even tried no FA and just the wifi, wifi not being recognized at all. I did try the wifi on a laptop and it seems to work. My next trial will be the Wifi on a different Pi.

So TL:DR, USB extension cable was the culprit.


#9

Last year I faced same problem using $2 unbranded WiFi dongle RTL8188CUS from eBay/China

Solved by following:
FA ProStick - Directly into Pi
WiFi Dongle - Through extender cable, away from Pi & ProStick.

WiFi


#10

I think that the circuitry in a short WiFi dongle is so close to all other circuits (FlightAware USB dongle) and the Raspberry PI unit itself that internal mixer frequencies radiate out and interfere. It is not the WiFi signal but the circuitry creating it. I have, however, no issues with the built-in WiFi on the Raspberry PI board. Their engineers probably considered the potential for internal circuit RFI and remedied it in their board and component design.


#11

Just to add another twist to everything, I was able to get the wifi + flightaware working together. Put everything back together and now i’m getting BETTER reception than I was originally getting. Its possible i just happen to be catching a busy time right now but i’m happy enough.

This is with both the wifi and flightaware sticks directly connected to the Pi (2).

Next step to try it all in my attic and see if things work well in there.