[USRP-users] [Discuss-gnuradio] New UHD seems to break a lot...

Ralph A. Schmid, dk5ras ralph at schmid.xxx
Fri Apr 17 13:00:39 EDT 2015


OK, here we go. The hotel TV was dvb-c only, so I had to do the tests back
at home. 

I took my perfectly working Kubuntu 14.04 64 bit VM container together with
my B210, made a copy and updated this one, first I made a git pull to get
latest master, built it, rebuilt gnuradio, rebuilt gr-dvbt, updated the FPGA
images, and everything still was fine. The chosen dvb-t bandwidth is 8 MHz.

Then I changed to 003_008_003_rc1, did the same procedure, fired up grc, and
the signal was not decodable both with a dvb-t PC receiver and with an dvb-x
analyzer. The analyzer saw the RF level, but no data, no constellation,
nothing, it looked to him like interference. 

When you have a look at the two "uhd" screenshots here
http://dk5ras.dyndns.org/tmp/DVB/ made with my spectrum analyzer then you
will find that RC1 produces a somehow narrower signal, so it really looks
something gets cut at the ends with all the filtering and DSP stuff.
Adjusting the channel bandwidth in the uhd sink block from 0 to a sensible
value changes nothing. 

Btw., the dvb-t2 package behaves identical.

Ralph.


-----Original Message-----
From: Martin Braun [mailto:martin.braun at ettus.com] 
Sent: Wednesday, April 15, 2015 21:14
To: Ralph A. Schmid, dk5ras; usrp-users at lists.ettus.com; 'GNU Radio
Discussion List'
Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot...

master works, but RC1 does not? Huh, I'm confused now. Can you give some
detail on what's going on, so we can try and reproduce this?

Thanks,
Martin

On 15.04.2015 12:52, Ralph A. Schmid, dk5ras wrote:
> RC1, master seems to work.
>
> Ralph.
>
> -----Original Message-----
> From: Martin Braun [mailto:martin.braun at ettus.com]
> Sent: Wednesday, April 15, 2015 15:44
> To: Ralph A. Schmid, dk5ras; usrp-users at lists.ettus.com; 'GNU Radio 
> Discussion List'
> Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot...
>
> Thanks, Ralph. Just to clarify: When you say 'New UHD', do you mean 
> 3.8.3-RC1, or latest master?
>
> Martin
>
> On 15.04.2015 08:40, Ralph A. Schmid, dk5ras wrote:
>> It is a B210, but as a note, due to the up to now missing FPGA images 
>> I used 003.008.003-RC1, not the latest master. Still I had no access 
>> to a spectrum and DVB-T analyzer, so I have no idea what is 
>> happening, I just can confirm that RF is transmitted, and the 
>> receiver doesn't get a picture, while with the snapshot of the same 
>> VM before the upgrade
> is received without problems.
>> I will know more in about three hours.
>>
>> Ralph.
>>
>>> -----Original Message-----
>>> From: Martin Braun [mailto:martin.braun at ettus.com]
>>> Sent: Wednesday, April 15, 2015 3:15 PM
>>> To: Ralph A. Schmid, dk5ras; usrp-users at lists.ettus.com; 'GNU Radio 
>>> Discussion List'
>>> Subject: Re: [Discuss-gnuradio] New UHD seems to break a lot...
>>>
>>> On 15.04.2015 06:20, Ralph A. Schmid, dk5ras wrote:
>>>> Hi,
>>>>
>>>> Not only OpenBTS is affected, also gr-dvbt/t2 do not work any more 
>>>> with latest uhd. A quick check during lunch break showed, the 
>>>> produced output is not decodable any more. I will take a closer 
>>>> look this evening at home, where I have more and better equipment.
>>>
>>> Ralph,
>>>
>>> which device is this on?
>>>
>>> Thanks,
>>> Martin
>>
>
>


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