[beagleboard] Re: Beaglebone Black, GPS, and RF interference

2020-11-23 Thread Mike Baranishyn 
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:
>
>
> 
> Spectrum with BBB Off:
>
>
> 
>
>
> 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!
>>
>

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Re: [beagleboard] Re: Beaglebone Black, GPS, and RF interference

2020-11-23 Thread Thomas Kaminski 
Mike,

Yes -- I disabled the video channel and it went away.  I did not use it for
the project.

I gave a talk on SDR and small systems -- it is available here:
https://drive.google.com/file/d/0B0I7pqe_KM9tcExvY3RwOUdhOGc/view?usp=sharing

Tom Kaminski

On Mon, Nov 23, 2020 at 8:48 AM Mike Baranishyn 
wrote:

> 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:
>>
>>
>> 
>> Spectrum with BBB Off:
>>
>>
>> 
>>
>>
>> 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!
>>>
>> --
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> .
>

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[beagleboard] Correct way to Update BBX15 Kernel to preempt_rt Kernel?

2020-11-23 Thread Daniel Block 
I found Mark Yoder's instructions for updating the BeagleBone's kernel to 
the preempt_rt kernel at https://elinux.org/EBC_Exercise_36_PREEMPT_RT  
 Thanks Mark.
  
I performed the same steps on my BeagleBoard X15 board except I used the 
command:
sudo ./update_kernel.sh --ti-rt-kernelinstead of  sudo 
./update_kernel.sh --bone-rt-kernel

Was that correct for the BBX15?  It ran and seems to have updated the 
kernel to the rt kernel according to uname -a.  I saw a few warnings as the 
install printed messages to the console so I want to make sure I performed 
this correctly.  

Thanks



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Re: [beagleboard] Correct way to Update BBX15 Kernel to preempt_rt Kernel?

2020-11-23 Thread Robert Nelson 
On Mon, Nov 23, 2020 at 10:30 AM Daniel Block  wrote:
>
> I found Mark Yoder's instructions for updating the BeagleBone's kernel to the 
> preempt_rt kernel at https://elinux.org/EBC_Exercise_36_PREEMPT_RT   Thanks 
> Mark.
>
> I performed the same steps on my BeagleBoard X15 board except I used the 
> command:
> sudo ./update_kernel.sh --ti-rt-kernelinstead of  sudo ./update_kernel.sh 
> --bone-rt-kernel
>
> Was that correct for the BBX15?  It ran and seems to have updated the kernel 
> to the rt kernel according to uname -a.  I saw a few warnings as the install 
> printed messages to the console so I want to make sure I performed this 
> correctly.

--ti-rt-kernel is perfectly fine for the bbx15..

Regards,

-- 
Robert Nelson
https://rcn-ee.com/

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[beagleboard] PocketBeagle fragile?

2020-11-23 Thread Paul Beam 
I now have a stack of 5 PocketBeagles that I have managed to break one way 
or another over the past year -- usually, doing something stupid like 
probing with a scope and the probe slips and shorts something out.  The 
symptom is all the same -- just a brief flash of the power LED when you 
apply power or push the power button.   Does anyone know what fails?  My 
assumption is the Octavo SOC fails and I should just throw these away,  It 
does seem like there is something fragile.,

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