[Hackrf-dev] Static/warbling non reception issue
Cinaed Simson
cinaed.simson at gmail.com
Sun May 1 16:47:46 EDT 2016
On 05/01/2016 01:13 PM, davidmarkusgoldstein at gmail.com wrote:
> I'd even consider buying studio1, if I can get this to work. I posted
> the basic settings screens...the signals are strong on the spectrum.
> Everything's just so inaudible and static'd.
>
What is your sampling rate? Did you try turning it down?
A sampling rate of 4-5 times the bandwidth is sufficient. WBFM is
roughly 200 kHz - a sampling rate of 1.75 MHz is sufficient.
It might not be the sound card - it might be the USB dropping data.
>
> Sent via the Samsung Galaxy Note® II, an AT&T 4G LTE smartphone
>
>
> -------- Original message --------
> From: Cinaed Simson
> Date:05/01/2016 3:49 PM (GMT-05:00)
> To: hackrf-dev at greatscottgadgets.com
> Subject: Re: [Hackrf-dev] Static/warbling non reception issue
>
> 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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>>
>
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