Why WiFi instead of bluetooth for portable ADS-B?

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Thunderbird83

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Thunderbird83
Maybe this is a stupid question...

Why do most of the portable ADS-B receivers connect over WiFi instead of Bluetooth? Connecting over WiFi means my cell phone loses its data connection as soon as I connect to a Stratus.

The only receiver that I know of that uses Bluetooth is Garmin (GDL-39). Bluetooth seems much better, since I can still use my phone for data while connected to the GDL-39.

WiFi is designed for networking. Bluetooth is designed for connecting peripherals. Is there some technical reason why most of the receivers use WiFi?
 
Don’t know the technical reason, but based on my own experience I’ve had much fewer issues with WiFi the Bluetooth. WiFi is pretty darn reliable. I’ve had issues with Bluetooth in the past. Not sure what you mean as far as losing data connection. When flying above 5000 which I do most of the time I don’t get any data or cell phone reception anyway.


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Phones have bluetooth for intercom calls.....wifi not so much. I've not had an issue with my WIFI unit.
 
What kind of phone do you have that loses data if on WIFI? Or more specifically, where would you have WIFI access when you are connected to the plane's WIFI network?
 
I suspect one reason is that for Apple iOS Bluetooth requires special certification(read: money), except BLE which probably isn't useful for these types of devices, where WiFi devices don't.
 
I think our old Garmin GDL39-3D supports 4 or 5 Bluetooth connections simultaneously (not sure of exact number). I can say that on the last 5 flights I have had a iPad min 4 tablet and a Android Galaxy S2 tablet both connected at the same time, entire flight and no problems.

I kinda like the Bluetooth option. Its direct and leaves the tablet wifi available to connect to the FBO's wifi on the ramp.

Actually, I have never used a wifi based ADS-B in device. Do wifi ADS-B devices have their own SSID and then tablet connects directly to it?

I would think you would want a central wifi router in the plane. Then have all avionics and tablet connect to the same SSID. You could even mount a few small cameras such as looking down below, up above and back and also have them pump images through that same router to the tablet. I still might dabble with that one day :)

An obvious advantage of wifi over Bluetooth is bandwidth. If the ADS-B in devices we are dealing had lots more data the wifi would be the winner. And same goes for distance. Probably gonna get more distance from wifi but then again in these small planes everything is pretty close. Now if they start adding a camera to a ADS-B in device I don't think you would see Bluetooth.
 
Do wifi ADS-B devices have their own SSID and then tablet connects directly to it?

yes....I just power it up and start the WingX app.
 
Interesting, not sure I've seen this covered before. I have a GDL 39 and it connects via BT to Garmin Pilot on my tablet and my iPhone while also talking via harness to my Garmin 510. I assumed all ADSB periphs used BT - whoops.
 
I thought someone on the Stratux Reddit page had come up with a way to use the Stratux and another access point or hot spot to pass the internet through to your phone or tablet. That doesn’t totally solve the problem or really answer the original question, but seems germane here.
 
I understand the problem on this, and yeah, I'd really like it if my Stratux connected via Bluetooth instead of wifi.
 
aggie06 said:
I thought someone on the Stratux Reddit page had come up with a way to use the Stratux and another access point or hot spot to pass the internet through to your phone or tablet. That doesn’t totally solve the problem or really answer the original question, but seems germane here.
Click to expand...

When a cellular iPad is connected to Stratux via WiFi, it will figure out that the WiFi its connected to has no internet connectivity, will remain connected to it as a local network only, and will simultaneously use the cellular data to go to internet stuff.

If the iPad doesn’t have cellular data, and needs WiFi to tether to a phone to get Internet then other routing methods would have to be done. One way to do it would be to turn the Pi into a router and DHCP server and have dual WiFi USB devices in it, one allowing a connection from the iPad and the other using wpa_supplicant to make a client connection to the phone, and then setting up routing in the Pi to do it.

I believe someone has done this in the Stratux Slack channel in the past, but I don’t think that configuration is a “built in”. Fairly complex and to make to user friendly they’d need some web code to set up wpa_supplicant to connect to the phone on the second WiFi dongle.

Very “do-able” to set that all up if you’re familiar with Linux command line and Linux WiFi networking.

For phones that provide tethering over USB, that’d be another option with some basic router knowledge and Linux networking knowledge.

Might ask on their Slack or wherever else the devs hang out if anyone’s managed to find enough time to hack the dual networking thing into the main code base yet. Last I played with it was over a year ago.
 
A few advantages of WiFi: It doesn't require pairing, it can support many devices simultaneously, and it has higher data throughput.

Overall, I much prefer WiFi to Bluetooth. I think the FlightStream 510 only supports two Bluetooth connections at a time, so if my partner and I fly together, we have to turn off our phones or our iPads might not both connect. (I unpaired my phone from it for that reason.) Most of the Garmin devices that use Bluetooth also only "remember" 13 or so devices unless you reset them, so in a flying club type of situation, it has to be reset fairly frequently or the people who weren't in the first 13 have to re-pair it every single time they fly.

Connecting to a WiFi device without an internet connection used to keep you from getting data through the Cellular connection, as the designers used to assume that WiFi meant Internet. However, newer devices and software have gotten smarter, and will usually still use the cellular connection if they can't get to the Internet through the WiFi.
 
Once you have the ‘pairing’ issue behind you Bluetooth has several advantages over WiFi the first being it consumes far less power. Also Bluetooth has the concept of ‘profiles’ so it handles things like voice and telephony functions I.e. answer and hang up. In our plane we use Bluetooth for weather and traffic from the GTX-345 to our iPhones and iPads, phone calls from our iPhones to our headsets, audio from GMA-345 to the Virb camera and music to the GMA-345 from iPhones. It all works flawlessly. At the same time we can still use LTE from our iPads and iPhones to receives text messages and emails. There is a reason all automobiles use Bluetooth over WiFi for phone and music playing. It is a very well defined standard.
 
chartbundle said:
I suspect one reason is that for Apple iOS Bluetooth requires special certification(read: money), except BLE which probably isn't useful for these types of devices, where WiFi devices don't.
Click to expand...

I much prefer Bluetooth, leaving WIFI to auto-connect to an FBOs (or my hangar's) WIFI when the plane gets within range. I think WIFI has become the preferred method for exactly the reason Chartbundle stated. Another excellent reason why one day, pilots will probably move away from iOS and toward Android.
 
In addition to all the specified reasons, it's a million times easier to implement WiFi connectivity in your device than Bluetooth (especially if you omit encryption and thus the supplication). If you have a limited development budget, the choice is clear. The only reason Garmin uses Bluetooth is the battery life.

I think the right answer for the OP's problem is to have an infrastructure mode network in the airplane, and then have all devices onboard connect to it, including the portables that supply the data. Unfortunately, switching to this model will require software adjustments and additional configuration (e.g. the discovery of your Stratux now must be done within the network, not by BSSID). Protocols and implementations exist for this - just think about WiFi printers. But again, the mode has to be supported in devices.
 
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