I have the same problem with my BBB and an Adafruit GPS. I made a U shaped copper shield and put it under the board. If I connect the BBB common to the shield the GPS works great. When I remove the shield ground it get's weaker but is still better than with out the copper shield. I also tried a cast aluminum box without a lid and that fixed the problem but it's too big for my application.
On Sunday, November 17, 2013 at 3:59:52 PM UTC-8, [email protected] wrote: > > Hello everyone, > > Sorry for the repost. i had posted this on the BeaglBone group, but this > is a BBB issue. > > I am having some problems trying to use a GPS receiver with the BeagleBone > black. I connected a PMB-648/688 module to one of the BBB UART ports. I can > see the NMEA messages coming from the GPS receiver, but I never get a valid > fix. I doesn't report any satellites in view (GPGSV messages). Not even if > I leave it on my rooftop for a couple hours. > > Initially I thought it might be a problem with the GPS receivers, so I > tested them on my laptop. Every one of the receivers I have worked fine, > taking a less than a minute to get a fix from my window. > > The next thing i thought was that there might be some power supply noise > messing with the GPS receiver, so I tried powering the receiver by itself > (connecting the grounds of my receiver supply and the BBB). Surprisingly, > this worked. More surprisingly, it stopped working If I moved the BBB close > to the GPS receiver. > > This lead me to suspect that the BBB might be causing some RF interference > on the GPS frequency band. My next test was to have the GPS receiver and > the BBB powered independently. This confirmed my suspicion. If I powered > the GPS receiver, waited until it got a valid GPS fix, powered the BBB, and > placed the BBB close to the GPS receiver, the I would get the same result > as before. No GPS fix, no satellites in view. Since the two devices are > being powered with two independent power sources, then the BBB must be > causing some RF interference. I do not have a RF spectrum analyzer to > confirm this, but I do not see any other reason.I tested this with three > different BBB and 6 different PMB-648/688. I always got the same result. > > I tried the same GPS receiver on a Raspberry Pi and It works fine, so that > is what I am going to work with for the moment. But I really like the BBB, > and would love to use it for my application. Is there anything I could do > to fix this? > > I'm sure other people have used GPS receivers with the BBB. Can anyone > recommend a GPS receiver that works with the BBB? I'm looking for a > receiver that's approximately the same size (3cm*3cm) and price ($35-$40) > as the PMB-648/688. I'm getting the Adafruit Ultimate GPS soon, so I'll > report about that. > > Thanks! > > --Juan Camilo > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/731892d1-2cab-4712-bffa-0d3768e9e7a7%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
