What Bluetooth GPS module to go with iPad?

[Rebelrabbit]

Using cellular enabled iPad with WINGS-X which works great bimbling along a 172 cockpit.

Also works pretty great flying commercial (isle seat on Southwest) during taxi to takeoff. All data fields are updating excellently.

Once above 12000ish ft. the GPS discombombulates and simply doesn't feed anything anymore into WINGS-X any longer.

Noted the 737-800 is essentially a Faraday cage entombing the iPad GPS from receiving any signals, however it does seem to feed GPS data while on the ground and during TO.

With this in mind wondering if anyone has some experience using external Bluetooth GPS modules that may offer increased reception from the tiny windows through which to pick up any semblance of the tiniest GPS signal that may get through.

Hoping to hear from those who have actual experience with suggesting Bluetooth GPS modules that may offer improved reception whilst dealing with the 500kts the 737 flies at.

Thank you for your replies.

V

 

[Ed Haywood]

Radio waves are line of sight. No amount of electronic magic is going to bend them from the window to an aisle seat. Get a window seat and hold your iPad flat against the window and it will pick up GPS just fine. It's gotta see the satellites to hear them.

 

[Stewartb]

My iPhone and Garmin Pilot work fine from the aisle seat.

 

[RussR]

A Sentry in the overhead bin will apparently work just fine, as I discovered one day when mine was in my flight bag overhead and the button pressed against something, turning it on.

 

[Cap'n Jack]

I use a Bad Elf. I use the lanyard to hang it someplace near the window, and it is still long enough that I can clip it to myself so I don't forget the GPS leaving the plane. It is small enough that I can tuck it under the window shade, so I can see on the map more detail than the plan's map shows. I get a nice track for geotagging photographs from this. Either synchronize the GPS and camera clocks, or take a picture at a known location during departure so that you know the camera clock offset.
Note that the Boeing 787 electronic shades block GPS signals. UAL flight crews tend to override the local control of window shades on international flights (pre-pandemic).

 

[Rebelrabbit]

Radio waves are line of sight. No amount of electronic magic is going to bend them from the window to an aisle seat. Get a window seat and hold your iPad flat against the window and it will pick up GPS just fine. It's gotta see the satellites to hear them.

Ed, if you can see outside (sky, ground, horizon) the window from the aisle seat then you are also able to receive signals along the same path.

Stewartb, RussR an Cap'n Jack thank you for your input and replies. Haven't ever heard of any of those devices. Plenty to look into.

And on a totally different note...

Curious how the Sentry compares to a Stratux, compares to the Bad Elf. Using instructor's Stratux to remain under and away from the B shelf. Sentry and Bad Elf is more sleek (yet Sentry almost double the price). The antennas of the Stratux seems better to render signals. Will eventually get something to feed the iPad.

Otherwise paper charts

Victor

 

[RussR]

Curious how the Sentry compares to a Stratux, compares to the Bad Elf. Using instructor's Stratux to remain under and away from the B shelf. Sentry and Bad Elf is more sleek (yet Sentry almost double the price). The antennas of the Stratux seems better to render signals. Will eventually get something to feed the iPad.

Not that familiar with the Bad Elf other than hearing a lot about it early on in the iPad days - is it just GPS, or ADS-B too? The others are ADS-B as well, which means they aren't really a direct comparison.

As for Stratux vs Sentry, the Stratux is a fine device. I have one myself, which I made back before they were available as pre-assembled units like they are now. But I am in and out of a lot of planes, do some ferrying, need to airline back and forth some times, etc. And to me, the bulkiness of the Stratux is its downfall for uses like mine. I mean, the antennas, the separate battery, etc. Heck, I could see TSA stopping you for extra checks because the thing actually looks like a bomb out of some Hollywood movie!

For my use, the size of the Sentry is great. It's like two decks of cards. Integrated battery that lasts for something like 12 hours. No antennas sticking out.

 

[Cap'n Jack]

Not that familiar with the Bad Elf other than hearing a lot about it early on in the iPad days - is it just GPS, or ADS-B too? The others are ADS-B as well, which means they aren't really a direct comparison.

As for Stratux vs Sentry, the Stratux is a fine device. I have one myself, which I made back before they were available as pre-assembled units like they are now. But I am in and out of a lot of planes, do some ferrying, need to airline back and forth some times, etc. And to me, the bulkiness of the Stratux is its downfall for uses like mine. I mean, the antennas, the separate battery, etc. Heck, I could see TSA stopping you for extra checks because the thing actually looks like a bomb out of some Hollywood movie!

For my use, the size of the Sentry is great. It's like two decks of cards. Integrated battery that lasts for something like 12 hours. No antennas sticking out.

The Bad Elf is GPS only. I still use it in conjunction with a non-GPS Stratux that I built.
There's a small ADSB receiver that may be useful:
https://uavionix.com/products/pingusb/

 

[Ed Haywood]

Ed, if you can see outside (sky, ground, horizon) the window from the aisle seat then you are also able to receive signals along the same path.
Victor

If that was the case, your iPad would receive in flight GPS just fine. And yet, it does not.

Here is a simple experiment I have performed many times. Hold your phone away from the window in an airliner in flight. You will not get a location lock. Then press the screen to the window for 1-2 minutes. You will get a lock.

By my math, diffraction of a 20cm GPS signal thru a 12 inch window is approx 30 degrees:

 

[Rebelrabbit]

If that was the case, your iPad would receive in flight GPS just fine. And yet, it does not.

Here is a simple experiment I have performed many times. Hold your phone away from the window in an airliner in flight. You will not get a location lock. Then press the screen to the window for 1-2 minutes. You will get a lock.

By my math, diffraction of a 20cm GPS signal thru a 12 inch window is approx 30 degrees:

View attachment 97075

Ed, the 12 inch window equates to approx 30 cm. No reason why a 20cm signal cannot fit through. I have no interest in willy waving with you or you trying to prove why the signal won't reach inside. An aisle seat perhaps no more than 40 inches from the windows does afford a reasonably good view and besides, defraction increases the lower in frequency. But I digress. I'm much more curious and interested to hear solutions. If you not able to contribute then we don't really have anything to gain either way. I'd still welcome any positive contributions you can suggest other than window seating! Can only refer you to my 1st post.

RussB, yes indeed, the homebrewed looking nature of the Stratux can certainly induce a fear amongst the "greater unwashed" aboard a typical 737-800 flight. If you were to whip out your Stratux, somewhere midflight, I'd imagine being rugby tackled in less time it takes to sneeze. Hogtied with cable ties, duct taped to the seat perhaps even missing out on the complimentary bag of peanuts and drink! The Sentry wins hands down in that department, pity the price though. $200 extra is a nice chunk towards a Bose A20! Thank you for your insights and input, I'm mildly envious of your ferrying SEPs and MEPs and whatnot! Bet you have some stories to tell.

And Cap'n Jack you absolutely disintegrated any high hopes I had for the Bad Elf! Just being a GPS at the same pricepoint as a Stratux makes it a difficult choice. Although all I really need is a Bluetooth GPS module. Some more hard thinking required to re-align priorities. Thank you for your insights and experience.

Victor - 172 student

 

[midlifeflyer]

I have a WiFi only iPad. I've used an XGPS150 for maybe 7 years, including on airlines. It's GPS only, no AHRS or ADS-B In, and sells for less than $100.

(Yes, I also have a Stratux for those few times I'm not flying something which already has a usable ADS-B and GPS and I care about having more than just location. But I can't imagine pulling my Stratux out on an airline when I can just strap the XGPS on my arm.)

 

[scarcherpilot]

I have a wifi only ipad. Before my plane had a GPS ADSB i could connect to (GNX375), i used a Bad Elf as well. Got me 2/3rds of the way across the country with no problems. Takes a minute or two to acquire the satellites and there is an app that goes with it to show you how many satellites it is finding. I think i paid $99 for it and it works like a champ when i have needed it. Never tried it on an airliner, but it is very tiny so it doesnt take up a bunch of room or likely arouse any suspicion from a flight attendant or Barny Fife TSA agent.

 

[Cap'n Jack]

Ed, the 12 inch window equates to approx 30 cm. No reason why a 20cm signal cannot fit through. I have no interest in willy waving with you or you trying to prove why the signal won't reach inside. An aisle seat perhaps no more than 40 inches from the windows does afford a reasonably good view and besides, defraction increases the lower in frequency. But I digress. I'm much more curious and interested to hear solutions. If you not able to contribute then we don't really have anything to gain either way. I'd still welcome any positive contributions you can suggest other than window seating! Can only refer you to my 1st post.

Actually, @Ed Haywood is mostly correct. I suspect he used the equations for a slit rather than for a (very roughly) circular aperture, but the results will be close enough. He also only showed the first order diffraction, but the higher orders will be weak so he properly ignored them. The wavelength of the GPS signal isn't much smaller than the window dimensions.

Besides that, I've some real-life experience. I might get a signal, and even a fix, at an aisle seat for a while, but I won't keep it, and I haven't been able to get another fix once the initial fix was lost.

RussB, yes indeed, the homebrewed looking nature of the Stratux can certainly induce a fear amongst the "greater unwashed" aboard a typical 737-800 flight. If you were to whip out your Stratux, somewhere midflight, I'd imagine being rugby tackled in less time it takes to sneeze. Hogtied with cable ties, duct taped to the seat perhaps even missing out on the complimentary bag of peanuts and drink! The Sentry wins hands down in that department, pity the price though. $200 extra is a nice chunk towards a Bose A20! Thank you for your insights and input, I'm mildly envious of your ferrying SEPs and MEPs and whatnot! Bet you have some stories to tell.

And Cap'n Jack you absolutely disintegrated any high hopes I had for the Bad Elf! Just being a GPS at the same pricepoint as a Stratux makes it a difficult choice. Although all I really need is a Bluetooth GPS module. Some more hard thinking required to re-align priorities. Thank you for your insights and experience.

Victor - 172 student

About the only time I've wished for the ADSB in was to know if another plane would be in sight so I can set up to get a picture; other aircraft are usually visible for only a few seconds from a passenger's perspective and they are usually gone or at a bad angle by the time I grab my camera. The GPS has been much more helpful in showing where we are going so I can tell if there is something interesting to image or look at. The GPS is better for my purposes but I recognize your needs may be different.

 

[Doug Reid]

If you have a cellular capable ipad, you have pretty decent gps capability. It is interesting to me that you get gps on the ground and not in flight above 12k. The gps sats are in orbit, not on the ground...maybe you are not using the internal gps, but using wifi location info instead. Why not try a gps diagnostic app first to verify your gps is an issue ?

 

[Stewartb]

The difference on my iPhone for position acquisition between a window or aisle seat is time. It take longer in the aisle. If your iPad isn’t picking up signal I’d guess you have an older iPad. My Mini 4 doesn’t do anything as well as my iPad Pro, including receive GPS. My Pro works fine on airliners, too. My Mini lives on my Cessna’s panel and does everything I need it to do in that plane.

If you’re in the market for a supplemental GPS receiver look to add ADHRS. That’s a valuable tool. If all you want is to see where you are while on an airliner? Try upgrading your iPad or get a cheap external receiver like a Garmin Glo.

 

[Ed Haywood]

I'd still welcome any positive contributions you can suggest other than window seating!

LOL. My positive contribution is this: until you understand why your iPad GPS reception does not work at altitude, you cannot know if a different device will work better, so you are potentially wasting your money.

Your OP said something about GPS not working because the jet is going 500mph. That is a fascinating theory. Tell me more.

 

[Rebelrabbit]

I flew commercial this weekend and here's some interesting findings discovered. WingsX locked GPS sats on the ground ALL the way up to our cruise alt of 36000ft!

WOW, WOW, WOW!

This naturally suggests there is GPS signals being received INSIDE the Faraday cage of the airliner!

Only after I interrupted WingsX (and restarted it again) did it fail to re-acquire lock on GPS sats!.

Upon suggestion of "scarcherpilot" + "Doug Reid"(thanks!) I also downloaded some GPS analysis app to check against what WingsX is getting. The app also reflected same as what WingsX was encountering.

During decent through 27000ft-ish did both WingsX and GPS app come alive with data.

iPad was purposely put in Airplane mode for the duration of the experiment. No Bluetooth, no wifi no cellular.

I have a WiFi only iPad. I've used an XGPS150 for maybe 7 years, including on airlines. It's GPS only, no AHRS or ADS-B In, and sells for less than $100.

(Yes, I also have a Stratux for those few times I'm not flying something which already has a usable ADS-B and GPS and I care about having more than just location. But I can't imagine pulling my Stratux out on an airline when I can just strap the XGPS on my arm.)

Thanks, this does look like a viable option as well.

I have a wifi only ipad. Before my plane had a GPS ADSB i could connect to (GNX375), i used a Bad Elf as well. Got me 2/3rds of the way across the country with no problems. Takes a minute or two to acquire the satellites and there is an app that goes with it to show you how many satellites it is finding. I think i paid $99 for it and it works like a champ when i have needed it. Never tried it on an airliner, but it is very tiny so it doesnt take up a bunch of room or likely arouse any suspicion from a flight attendant or Barny Fife TSA agent.

Thanks for suggesting a GPS app, added valuable proof to what was going on. Also keen on adding a cheapish GPS bluetooth, pity the Bad Elf is sooo pricy. I tried re-acquiring the GPS sats all along the flight and at no time could my iPad re-acquire and lock for the duration of the rest of the flight despite numerous restarts during remaining 2 hours at cruise.

I might get a signal, and even a fix, at an aisle seat for a while, but I won't keep it, and I haven't been able to get another fix once the initial fix was lost.

About the only time I've wished for the ADSB in was to know if another plane would be in sight so I can set up to get a picture; other aircraft are usually visible for only a few seconds from a passenger's perspective and they are usually gone or at a bad angle by the time I grab my camera. The GPS has been much more helpful in showing where we are going so I can tell if there is something interesting to image or look at. The GPS is better for my purposes but I recognize your needs may be different.

Same experience found, couldn't re-acquire lock on GPS sats once lost.

If you have a cellular capable ipad, you have pretty decent gps capability. It is interesting to me that you get gps on the ground and not in flight above 12k. The gps sats are in orbit, not on the ground...maybe you are not using the internal gps, but using wifi location info instead. Why not try a gps diagnostic app first to verify your gps is an issue ?

Have the latest iteration of iPad and as stated earlier was able to acquire lock on GPS sats well into cruise at 36000ft.

This naturally suggests there is GPS signals being received INSIDE the Faraday cage of the airliner!

Only when WingsX (and GPS app) closed down and restarted was it not able to reacquire lock on GPS sats. iPad was purposely put in Airplane mode for the duration of the experiment.

WingsX and GPS app did come alive with GPS lock and ensuing data in descent through 27000ft-ish.

The difference on my iPhone for position acquisition between a window or aisle seat is time. It take longer in the aisle. If your iPad isn’t picking up signal I’d guess you have an older iPad. My Mini 4 doesn’t do anything as well as my iPad Pro, including receive GPS. My Pro works fine on airliners, too. My Mini lives on my Cessna’s panel and does everything I need it to do in that plane.

If you’re in the market for a supplemental GPS receiver look to add ADHRS. That’s a valuable tool. If all you want is to see where you are while on an airliner? Try upgrading your iPad or get a cheap external receiver like a Garmin Glo.

Agreed, I'm pretty certain an acquisition lock on GPS sats will certainly improve sitting window seat, although this is not where I prefer to seat myself when flying commercial.

Merely a matter of doing some research into what GPS bluetooth to get. Interesting times indeed!