Was this ever solved? On Monday, July 7, 2014 at 12:05:37 AM UTC-4 tjkami...@gmail.com wrote:
> I have measured Beaglebone Black radiated energy around the 1575 MHz band > that GPS uses with an SDR spectrum analyzer using GPRS on a MacBook Pro. It > does not seem to be harmonically related to the BBB Clock. It is possibly > related to the HDMI video circuit... > > Spectrum with BBB ON: > > > <https://lh6.googleusercontent.com/-3UzV31XcvwM/U7obp6C432I/AAAAAAAAGn8/75NV0_4m3xY/s1600/Spectrum_BBB_On_GPS.jpg> > Spectrum with BBB Off: > > > <https://lh6.googleusercontent.com/-P9o5Wic5lpQ/U7ob62YIRVI/AAAAAAAAGoE/a3dg1JSmZyQ/s1600/Spectrum_BBB_Off_GPS.jpg> > > > On Sunday, November 17, 2013 5:55:46 PM UTC-6, juanc...@gmail.com wrote: >> >> Hello everyone, >> >> Sorry for the reposted message. I had posted this on the BeagleBone >> group, but this is an issue with the BeagleBone Black. >> >> 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! >> > -- 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 beagleboard+unsubscr...@googlegroups.com. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/eb3028d4-701b-42e6-8270-b19fe32d1c27n%40googlegroups.com.
