Replies to This Discussion

Permalink Reply by Keith S on April 2, 2012 at 5:35pm

Do you have a picture to share? That might help..

 

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Permalink Reply by Glenn M on April 2, 2012 at 5:55pm

Yep here you go.

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Permalink Reply by Keith S on April 2, 2012 at 6:07pm

Thanks for sharing. It looks good to me, but I'm courious if your rx is too close. 

Something to try.

 

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Permalink Reply by Christopher Cooper on April 2, 2012 at 8:47pm

I don't think the RX would provide interference. It's only receiving, not transmitting.

I have had this issue in the past Glenn, but in the end it sort of went away. No idea if I did anything that fixed it, sorry! Though with mine I noticed on clear days it was hard to get a lock, whereas on overcast days I could get one almost right away.

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Permalink Reply by Glenn M on April 2, 2012 at 8:51pm

I wonder if cutting a few of the bars in the top fibreglass plate would help... I'll do some testing with the top plate off completely and see if there's much difference.

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Permalink Reply by Ken on April 6, 2012 at 3:39pm

>I don't think the RX would provide interference. It's only receiving, not transmitting.

.

OMG They surely do! Any receiver more advanced than a 1925 era crystal detector type receiver radiates. 

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ModeratorPermalink Reply by Adam AKAV8R on April 4, 2012 at 4:48pm

I have the same issue sometimes getting the initial fix, however I'm using a APM 2.0 Purple and mine is on the lower deck.  Sometimes hitting the reset button on the APM after you powered up and set on the ground where you plan on taking off from seems to help.

 

Adam

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Permalink Reply by Glenn M on April 4, 2012 at 11:28pm

OK cheers, I'll give it a go. Last few flights I have had 1, maybe 2 satellites max for the duration of the whole flight, so no lock. What exactly does hitting the reset button reset? Does it just soft reboot the board?

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Permalink Reply by emile on April 6, 2012 at 8:26am

If I remember correctly there was a problem with some Mediatek GPS were the current was lower than the 3.3 volts required.

Check the blue led, if it blinks slower than 1 per second then check the 3.3v that gets to the GPS.

if it's lower than 3.0v you could have a defective board.

Emile

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Permalink Reply by Ken on April 6, 2012 at 12:43pm

Is that slotted cover fiberglass or carbon fiber? If it is carbon fiber, then that is absolutely your problem. If it is glass, it could be a contributing factor.

Simple rule, always works: do NOT cover your GPS antenna.

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Permalink Reply by Glenn M on April 6, 2012 at 1:15pm

It's fibreglass. I tried it without the cover on at all the other day for 10 minutes and it still only managed 2 sats and no lock.

Blue light on the gps flashes once a second. Just tried cli erase/reset, and reuploaded firmware but no help.

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Permalink Reply by Vernon Barry on April 6, 2012 at 1:55pm

OK, so right now there are a number of external forces against us using GPS these days. One of them being the largest amount of solar activity in years which seriously affects the GPS signal. The next is that there is an experimental wireless WAN trial going on in the US and one of it's biggest problems is that it too is interfering with the GPS signals. This means that more than ever, you must have a clear line of site to the sky with nothing on top of a gps module in order to ensure the best GPS access. So yes, any fiberglass, plastic, and especially carbon fiber will degrade the signal to the point your GPS may not lock. It's not a problem with our modules, they are very good, but all GPS receivers are experiencing this. I used to be able a couple of months ago get a lock inside my house, now it takes some time even outside. DIfferent areas and different days are being affected by the combinations of radio interference and solar flares.

Apparently, the one source was shut down by the FCC

http://money.cnn.com/2012/02/15/technology/lightsquared_gps/index.htm

 http://www.pcworld.com/businesscenter/article/249584/feds_look_beyo...

Solar flares:

http://www.ips.gov.au/Educational/1/3/10

 http://www.engadget.com/2010/02/10/solar-flares-set-to-wreak-havoc-...

 

Also, I curious to see what happens with the new telemetry modules released today.433MHz and 915MHz might have harmonics that could interefere with an already weak GPS signal.

http://diydrones.com/profiles/blogs/announcing-the-3dr-radio-teleme...

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