Improved GPS reception?

[akbardotinfo]

yesterday I quite dissapointed by the result of allumunium foil cover of the gps module (last night 5-6 sat for 5 minutes), but after read this thread, I reopen my phantom and get the gps cable covered by alluminium foil tape, just now I put the phantom on the same place, and HOAAAAAA!!! got 7-8 sat in 20-30 second!!!!

THANKS A TONS TO THIS THREAD!!!

new problem: when I record a video up there the sat drop from 9 to 4-5 (

 

[E_T]

Sorry, didn't read all 15 pages of this thread, but can someone give me the TL;DR version? What is the best option at this point? Just moving the wire outside the stock shielding? I really don't want to put a bunch of aluminum in there if it's not going to do much more over just moving the wire. Thanks.

 

[robinb]

Sorry, didn't read all 15 pages of this thread, but can someone give me the TL;DR version? What is the best option at this point? Just moving the wire outside the stock shielding? I really don't want to put a bunch of aluminum in there if it's not going to do much more over just moving the wire. Thanks.

no you should read the 15 pages like the rest of us.

 

[N017RW]

Sorry, didn't read all 15 pages of this thread, but can someone give me the TL;DR version? What is the best option at this point? Just moving the wire outside the stock shielding? I really don't want to put a bunch of aluminum in there if it's not going to do much more over just moving the wire. Thanks.

The problems are many but for one this is being done in a ad hoc case by case basis so the results will vary.
There is no real consistency in the size, shape, and other manners of it's [shield] implementation across various users. Not to mention local geographic factors and non-controlled evaluations (in some cases).

The addition of these materials has both benefits and caveats.

Since this mod effectively increases the ground plane it [can] increase gain but it also [can] shifts the center or resonant frequency of the patch. These factors may work to your advantage, disadvantage, or even 'compete' with each other.

 

[E_T]

Sorry, didn't read all 15 pages of this thread, but can someone give me the TL;DR version? What is the best option at this point? Just moving the wire outside the stock shielding? I really don't want to put a bunch of aluminum in there if it's not going to do much more over just moving the wire. Thanks.

The problems are many but for one this is being done in a ad hoc case by case basis so the results will vary.
There is no real consistency in the size, shape, and other manners of it's [shield] implementation across various users. Not to mention local geographic factors and non-controlled evaluations (in some cases).

The addition of these materials has both benefits and caveats.

Since this mod effectively increases the ground plane it [can] increase gain but it also [can] shifts the center or resonant frequency of the patch. These factors may work to your advantage, disadvantage, or even 'compete' with each other.

Thanks. I'll have to investigate this further. I didn't think there'd be any downsides to trying this mod.

 

[E_T]

Just read the whole thread. I don't think I want to bother with foil. Maybe just putting the wire under the stock shielding would be worth trying for me. When I launch in my front yard, I typically only get 5 sats, until I get a little altitude. If I can get an extra one or two, I'd be happy.

 

[kirbinster]

yesterday I quite dissapointed by the result of allumunium foil cover of the gps module (last night 5-6 sat for 5 minutes), but after read this thread, I reopen my phantom and get the gps cable covered by alluminium foil tape, just now I put the phantom on the same place, and HOAAAAAA!!! got 7-8 sat in 20-30 second!!!!

THANKS A TONS TO THIS THREAD!!!

new problem: when I record a video up there the sat drop from 9 to 4-5 (

I did the fix and am now having the exact same problem it drops from 8-10 to below 6 when I turn on the video cam

 

[karmakazi]

Very strange, I've read so many comments about sats dropping when recording is started. I keep watching mine to see if it does the same thing and it never does. Today I went to a spot where I have trouble getting 7, once I did and gained altitude I was bouncing between 11 and 12. Can having cell service on the phone you are using to view what the phantom sees interfere? Just curious, I have a dedicated phone for my viewer with no cell service.

 

[Mori55]

yesterday I quite dissapointed by the result of allumunium foil cover of the gps module (last night 5-6 sat for 5 minutes), but after read this thread, I reopen my phantom and get the gps cable covered by alluminium foil tape, just now I put the phantom on the same place, and HOAAAAAA!!! got 7-8 sat in 20-30 second!!!!

THANKS A TONS TO THIS THREAD!!!

new problem: when I record a video up there the sat drop from 9 to 4-5 (

I did the fix and am now having the exact same problem it drops from 8-10 to below 6 when I turn on the video cam

Why do the mod if your getting 8-10 sats ??? I'd say you screwed up something when you did the mod. Did you I sulfate the foil ? Make sure you didn't losen a cable.

 

[Mori55]

Very strange, I've read so many comments about sats dropping when recording is started. I keep watching mine to see if it does the same thing and it never does. Today I went to a spot where I have trouble getting 7, once I did and gained altitude I was bouncing between 11 and 12. Can having cell service on the phone you are using to view what the phantom sees interfere? Just curious, I have a dedicated phone for my viewer with no cell service.

No. A lot of solar storms lately.

 

[E_T]

Would putting aluminum tape over the existing shielding, repositioning the wire under it and then putting packing tape over the exposed aluminum work OK?

 

[akbardotinfo]

quote="akbardotinfo"]yesterday I quite dissapointed by the result of allumunium foil cover of the gps module (last night 5-6 sat for 5 minutes), but after read this thread, I reopen my phantom and get the gps cable covered by alluminium foil tape, just now I put the phantom on the same place, and HOAAAAAA!!! got 7-8 sat in 20-30 second!!!!

THANKS A TONS TO THIS THREAD!!!

I did the fix and am now having the exact same problem it drops from 8-10 to below 6 when I turn on the video cam

I have my conclusion about this mods with my current location(in town), surely it make our gps faster to get gps sat, but its like "lie" with phantom condition it self, the condition is the interference of video recording effect to the gps receiver (only then video recording, not photo shutter).

I have 4 time test with different condition: with (1)allumunium cover the gps along with the gps cable, (2)only the gps module cover with allumunium foil tape, (3)only the gps cable I cover with allumunium foil tape: the three condition make phantom faster to get gps sat lock but when start recording it will drop your sat.

on 1 got the gps about 30 second and when it up there I got at least 10-11 sat, and it drop to 5 when I start recording
on 2 got the gps about 1-2 minutes and when it up there I got at least 8 sat and yes it drop to 5 when I start recording
on 3 got the gps about 2 minutes and when it up there I got at least 8 sat and yes it drop to 5 when I start recording

you can wait up there when it drop to 5 with video recording ( just to make sure the phantom get its real condition) until sat lock, but I would not do that.

but when I remove all the allumunium foil both gps cable and gps cover (no mods), yes I have to wait longer until at least the battery of my phantom to 97-96% to get sat lock, but when I got it fly and start recording I still have my gps sat lock (not drop under 6).

so I' remove the gps mods completelly from the bird.

thanks

 

[YeeaaBoii]

Has anyone had any negative effects from doing this mod like me? Before the mod, I was getting 5-6 satellites before takeoff and it took forever to hold 6 long enough to make a lock. Sometimes up to 5 minutes. All I did was put the cable underneath the stock shield and now it only gets 3-4 satellites. I have to take off in ATTI mode and take it up to over 100 feet to get a 6 satellite lock. Then if I fly higher, I could only get it up to 8 satellites. I used to get 12 satellites easily up at altitude before this mod. What's the deal?!

 

[Stile2112]

Just throwing this out there, but you could always do what I did and purchase a combined GPS/Compass from a Naza "Lite" and mount it externally. It's 100% compatible and there's simply no interference this way. Just remove the internal GPS and plug in the puck. The assistant may ask for an IMU calibration, but after that it's all smooth sailing.

GPS locks are fast, tight and stable, and the compass works beautifully. As you can see, I have an aftermarket landing gear which I modified to fit a P2V+, but there's no need to worry about compass mounting on the leg because it's all part of the combined GPS unit.

I went the elaborate route by snipping off the stock molex on the puck's cable, shortened it, and ran it through a grommet in the rear of the top shell, and then soldered on a new molex. That's much more elaborate than necessary though, as one could simply make a small cutout in the top shell and use the entire stock, intact cable without modification.

On the vision (original) there's only the one GPS port. On the Vision+ there are separate compass and GPS ports, but the GPS port still accepts compass signals through the GPS port, so it works fine on either flavor and probably works fine on a non vision as well.

Naza GPS/Compass Puck $100: http://www.banggood.com/DJI-NAZA-Lite-V ... 86239.html
Tarot GPS mount (works well on the curved surface because there's only one mounting point): http://www.banggood.com/Tarot-680-Pro-T ... 34829.html

Well I finally installed my external GPS just like Varmint did... Wow! what a difference. I now lock 10 to 11 sats every time now.... and quickly too. I don't loose a single sat when recording either.

It's a bit more involved then simply taping tin foil to the inside of the shell and it does cost about $100 to do it, but it was well worth it.

 

[akbardotinfo]

just update my experiment:

below is my latest mods after several mods done using allumunium foil for cooking and tape, and yes the gps drop under 6 when recording video.
and...
Now I'm using EMI COPPER SHIELD TAPE ONLY, about US$10 got it from http://www.twojah.com/parts-and-accessories

ok. the result? got satlock less than 3 minutes, and NO gps grop when recording video AWESOME

the clue or the copper shield under the battery got from http://youtu.be/1hKcUcZPWww

 

[DrJoe]

I had done the aluminum foil mod to protect my GPS signal strength. Never really had an issue, but after the mod, I found I acquired satellite lock faster and maintained higher readings.

This week, I received a new Flytrex 3G. The Flytrex has a cable that connects to the GPS wire coming from the puck at the top of the shell, then to the port on the main board, and finally with a pig-tail to the Flytrex unit. After installation of the Flytrex 3G unit, I noticed the satellite lock dropped significantly, and was more affected when recording. Even while flying, I'd drop below 6, when I had been getting about 9-12 satellites, even while recording.

I reread the posts in this forum. I figured the new interference was coming from the connecting wire that the flytrex uses. Once I removed the shell, I tried several different things.

• 1. Holding the shell above the unit to the length the wire would allow (about 7 inches) provided instant five satellites in my house.
  2. Placing several more sheets of aluminum foil between the gps puck in the shell and the phantom also provided the same result.

With this information, I decided that aluminum foil, at the correct thickness (about 64layers), does provide excellent shielding. I wasn't using enough in my original shield and the new, longer wire needed to be shielded too. With trial and error, I created a shield thick enough to provide excellent in door satellite lock, then covered it with duct tape, tucked the Flytrex wires under it (leaving just enough length to connect to the board) and put the shell back on.

Bingo! With the thicker shield and wires tucked behind it, I got excellent satellite lock (as I had been used to), even while recording. I was concerned with the additional weight of such a thick shield, but it has not affected the flight characteristics in any detectable way. I also fly with the Flytrex 3G box and an ND/petal filter for the camera. The additional weight has had no detectable effect.

The P2V+ v3 has taken steps to mitigate this problem with ferric donuts, etc, but for v1 owners, this foil mod is an absolute must.

• Losing GPS will cause the RTH function to fail, resulting in "flyaways".
  Losing GPS at a good distance will cause the loss of IOC, course lock and home lock functions, making the bird respond as if IOC was off, confusing some pilots and resulting in "flyaway".
  Losing GPS lock will cause the bird to switch to ATTI mode, and drifting with the wind (perhaps out of control range), and also causing "flyaways".

I believe DJI's poor design of the FC200 camera and the control board creates extreme RF interference that can easily result in loss of GPS signal, and subsequent loss of RTH, IOC, and GPS stabilization, with peak interference occurring during recording. With the use of copper or thick aluminum foil shielding, pilots can overcome this inherent design flaw and safely fly their birds.

 

[Couchie]

Ok, having just dropped a significant amount of money for my P2V+, I would assume everything works on it as it should. With that being said, why are we all trying to 'home fix' an issue that is obviously not unique to just one or two units. Should we as owners have some recourse with DJI to fix an issue that is one of the main selling points for the units?

Due to the issue with a lack of sufficient GPS reception, I have only tried using the ground station one time. Even then, the P2V+ would gain and lose signal often. Watching the phantom float around between the two points while losing GPS was quite nerving.

I have made it a habit of checking the GPS Plan app prior to flying. I never fly until I have at least 8 satellites available.

I notice the same issues many others have. On the ground, 7-9 satellites. In the air, recording video 4-5.

Should we not be pressing DJI to come up with fix that is a 'once and for all'?

 

[msinger]

Should we not be pressing DJI to come up with fix that is a 'once and for all'?

Sure. But, in the meantime, people are doing this mod to fix the problem. Who wants to keep their Phantom on the ground and wait for DJI to do something?

 

[Couchie]

I certainly understand. I am in the same boat! I too enjoy getting mine out and cruising around and shooting video/stills of different areas. BUT at the same time, I don't like the fact that one of the technologies I paid for to protect my investment from wandering off and ensuring it finds it's way back to where it started.

I have been reading the forums here, on DJI's site, and others covering this issue trying to decide which is the 'best fix'. I plan on trying these ideas as well but I would rather my fix just be something temporary with the hopes that DJI will come up with a permanent solution.

 

[msinger]

I would rather my fix just be something temporary with the hopes that DJI will come up with a permanent solution.

They did fix the problem (or improve it anyhow) by adding additional shielding. The only current "fix" offered by DJI is to buy version 3 of the Phantom.