[Hackrf-dev] Static/warbling non reception issue

Cinaed Simson cinaed.simson at gmail.com
Sun May 1 15:49:09 EDT 2016


On 05/01/2016 06:38 AM, David Goldstein wrote:
> Maybe someone has an extio that will fix this...?

Yes there is an extio - the poster could supply the list with the
parameters he's using and his hardware setup.

> 
> On Apr 30, 2016 11:39, "Dominic Spill" <dominicgs at gmail.com
> <mailto:dominicgs at gmail.com>> wrote:
> 
>     I can't remember how it works in SDR#, but in GQRX you can just click
>     on the display and it will start demodulating that frequency instead
>     of the centre frequency.  It's probably the same in SDR#
> 
>     Dominic
> 
>     On 30 April 2016 at 16:36, davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>
>     <davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>> wrote:
>     > Hi Dominic,
>     >
>     > Yeah 101.5 and 103.3 are right in town or nearby.  I will have to
>     test the
>     > offset features better...I will let you know how this goes.
>     >
>     > David
>     >
>     >
>     > Sent via the Samsung Galaxy Note® II, an AT&T 4G LTE smartphone
>     >
>     >
>     > -------- Original message --------
>     > From: Dominic Spill
>     > Date:04/30/2016 11:23 AM (GMT-05:00)
>     > To: david.goldstein.93 at alumni.vanderbilt.edu
>     <mailto:david.goldstein.93 at alumni.vanderbilt.edu>
>     > Cc: hackrf-dev
>     > Subject: Re: [Hackrf-dev] Static/warbling non reception issue
>     >
>     > On 30 April 2016 at 00:32, David Goldstein
>     > <davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>> wrote:
>     >> Hi, here's a screenshot of the settings that I can change, plus the
>     >> spectrum analysis shot.  The audio I get is heavily distorted on
>     the strong
>     >> local FM stations.
>     >
>     > The station at 101.5MHz looks like an excellent signal.
>     >
>     >> So, I have no idea what's wrong, except that it could be the
>     sound driver
>     >> or on-board sound.
>     >
>     > Are you demodulating the signal at the centre frequency?  Or at an
>     > offset?  The spike in the middle is the DC offset, so if you're
>     > demodulating there you're going to see bad data.  It's explained in
>     > more detail here:
>     >
>     https://github.com/mossmann/hackrf/wiki/FAQ#what-is-this-big-spike-in-the-center-of-my-received-spectrum
>     >
>     > Thanks,
>     >   Dominic
>     >
>     >> -----Original Message-----
>     >> From: Dominic Spill [mailto:dominicgs at gmail.com
>     <mailto:dominicgs at gmail.com>]
>     >> Sent: Friday, April 29, 2016 5:40 PM
>     >> To: davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>
>     >> Cc: hackrf-dev
>     >> Subject: Re: [Hackrf-dev] Static/warbling non reception issue
>     >>
>     >> On 29 April 2016 at 17:31, davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>
>     >> <davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>> wrote:
>     >>> Hi, how can I test the hackrf to see if it's damaged?  I have sound
>     >>> card issues, it seems, on my i7-2600 win7 64 bit system, so I
>     tried it
>     >>> on a Vista laptop and experienced the same: static and
>     choppiness and
>     >>> some distorted voice on local fm.  So perhaps the radio is damaged.
>     >>
>     >> This doesn't necessarily mean that the radio is damaged, although
>     we can
>     >> help to test whether it is, but it may be something not quite
>     right in your
>     >> settings.  Telling us which settings you are using for sample
>     rate, gain,
>     >> filter, etc would really help us to diagnose the problem.
>     >>
>     >> Thanks,
>     >>   Dominic
>     >>
>     >>> -------- Original message --------
>     >>> From: Dominic Spill
>     >>> Date:04/28/2016 7:31 PM (GMT-05:00)
>     >>> To: davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>
>     >>> Cc: hackrf-dev
>     >>> Subject: Re: [Hackrf-dev] Static/warbling non reception issue
>     >>>
>     >>> On 28 April 2016 at 20:28, davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>
>     >>> <davidmarkusgoldstein at gmail.com
>     <mailto:davidmarkusgoldstein at gmail.com>> wrote:
>     >>>>
>     >>>> Hi, this might not be a tech support list but I don't know what
>     to do
>     >>>
>     >>> Hi David,
>     >>>
>     >>> We're happy to provide tech support through this mailing list; I'm
>     >>> sure we'll be able to help you.
>     >>>
>     >>>> ...everything seems set up properly but I get static and broken up
>     >>>> voice broadcast on local fm.  I think it's the alc889 Realtek sound
>     >>>> card doing this...I had this issue with a winradio g 315
>     because I'm
>     >>>> running win 7 64bit.
>     >>>
>     >>> Are you using SDR# on your Win7 install?  Could you give us some
>     >>> examples of the settings you are using?  If it's easier, you can
>     >>> attach a screenshot of the setting panel in SDR# (or whichever tool
>     >>> you're using).  You could also attach a screenshot of the tool
>     so that
>     >>> we can see how strong the signal is compared to the background
>     noise.
>     >>>
>     >>>>  They tweaked a driver for me and I got the winradio running but I
>     >>>> don't know what to do now with the hackrf I have, if it is the
>     sound
>     >>>> card at all.  Any tips?
>     >>>
>     >>> One option would be to try not using realtime processing. 
>     Capture ~20
>     >>> seconds FM station to a file, then demodulate it from the file
>     >>> afterwards.  Finally, you should be able to play back the file as
>     >>> audio.  If it's a problem with the quality of the signal being
>     >>> received, the output will still be choppy, but if the output is
>     smooth
>     >>> we can look at where else things may be going wrong.
>     >>>
>     >>> It certainly looks like you have enough CPU power and RAM to support
>     >>> the task that you're trying to do, so we'll have to narrow down
>     where
>     >>> the problem could be.
>     >>>
>     >>> Thanks,
>     >>>   Dominic
> 
> 
> 
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