[Hackrf-dev] FM receive difference between HackRF and RTL-SDR

[Mike Jameson]

If it works in GRC then it means that the problem is not with your HACKRF
but with GQRX.  Now that you mention it there is a constant 'hiss' when
listening to WFM-stereo broadcast stations with a low sampling rate.  The
hiss goes away with WFM-mono and also when the sampling rate is set to
20000000.

FYI, here are my gain settings:

RF Gain: 14.0
IF Gain: 24.0
BB Gain: 40.0
Audio Gain: 10.5

Remember not to have the radio station on the exact center frequency as the
DC carrier is either in the way or you lose a bit from the DC removal
feature (the box called 'DC rem.').

Try all this with the ANT500 supplied antenna as short as you can make it.

Mike

--
Mike Jameson M0MIK BSc MIET
Email: mike at scanoo.com
Web: http://scanoo.com

On Mon, Sep 22, 2014 at 4:38 PM, Mehdi Asgari <mehdi.qbic at gmail.com> wrote:

> I'd already updated the SPI. I upadted the CPLD too.
> I managed to get a good quality in GRC (before  updating), but not in Gqrx.
> What would you do in this scenario? What should be checked to make sure
> everything is OK?
> Could this be a problem if Gqrx?
>
> On Mon, Sep 22, 2014 at 6:49 PM, Mike Jameson <mike at scanoo.com> wrote:
>
>> Have you updated both the 'SPI Flash' and 'CPLD' firmware and rebooted
>> the hackrf in between?  Instructions below:
>>
>> https://github.com/mossmann/hackrf/wiki/Updating-Firmware
>>
>> Mike
>>
>> --
>> Mike Jameson M0MIK BSc MIET
>> Email: mike at scanoo.com
>> Web: http://scanoo.com
>>
>> On Mon, Sep 22, 2014 at 4:00 PM, Mehdi Asgari <mehdi.qbic at gmail.com>
>> wrote:
>>
>>> Thank you Mike.
>>> I tried the above items, but there's no significant change in result.
>>> I can clearly hear the radio, but it still comes with noise (In fact
>>> I've played with every config that I thought is related, but I can't reach
>>> the same quality level that I am receiving via RTL-SDR)
>>>
>>> On Mon, Sep 22, 2014 at 6:04 PM, Mike Jameson <mike at scanoo.com> wrote:
>>>
>>>> Some things to try:
>>>>
>>>> 1) Make your antenna as small as possible as you may be overloading
>>>> it.  Broadcast FM stations are strong!
>>>> 2) Reduce the gain on all three gqrx gain controls (RF,IF & BB).  Try
>>>> just raising IF until the signal appears.
>>>> 3) Set the center frequency to something slightly above or below the
>>>> target frequency and click on the wanted frequency.
>>>> 4) Set the sampling rate to 10e6 (10M)
>>>> 5) Start GQRX using a fresh config with 'gqrx -r'
>>>>
>>>> Mike
>>>>
>>>> --
>>>> Mike Jameson M0MIK BSc MIET
>>>> Email: mike at scanoo.com
>>>> Web: http://scanoo.com
>>>>
>>>> On Mon, Sep 22, 2014 at 3:18 PM, Mehdi Asgari <mehdi.qbic at gmail.com>
>>>> wrote:
>>>>
>>>>> Hmmm, I am using the last version of tools (and I don't know how
>>>>> should I change the magnitude)
>>>>> By the way, why the same setup in Gqrx produces different outputs for
>>>>> RTL-SDR and HackRF One?
>>>>> Here's a link to two screenshots from Gqrx window which may be helpful.
>>>>> HackRF: http://i60.tinypic.com/o7127d.png
>>>>> RTL-SDR: http://i57.tinypic.com/10r79lc.jpg
>>>>>
>>>>> Thanks
>>>>> Mehdi
>>>>>
>>>>> On Mon, Sep 22, 2014 at 4:54 PM, Simon IJskes <simon at ijskes.org>
>>>>> wrote:
>>>>>
>>>>>> The experience sounds the same as my first attempt, under linux, with
>>>>>> the old osmosdr software, where the magnitude of the signal was incorrectly
>>>>>> assumed to be unsigned.
>>>>>>
>>>>>> After fixing this, it all sounded a whole lot better.
>>>>>>
>>>>>> Maybe this is also the case in your setup?
>>>>>>
>>>>>> Gr. Simon
>>>>>>
>>>>>>
>>>>>> On 22-09-14 15:08, Mehdi Asgari wrote:
>>>>>>
>>>>>>> Hi
>>>>>>> I am a beginner in SDRs (and DSP)
>>>>>>> For the first sample, I'm, trying to build a FM receiver. I've tried
>>>>>>> both RTL-SDR and HackRF One (with both GNU Radio and Gqrx)
>>>>>>> I can easily get the desired station (on 88.0 MHZ) without noise on
>>>>>>> RTL-SDR (using Gqrx or GRC)
>>>>>>> But when I use HackRF One (with Gqrx or GRC), I can get the radio,
>>>>>>> but
>>>>>>> it's noisy.
>>>>>>> Is is because HackRF's higher sensitivity or does it need more
>>>>>>> adjustment to work fine?
>>>>>>>
>>>>>>> Note 1: I am using GNU Radio Live DVD and HackRF One with firmware
>>>>>>> 2014.08.1 and RTL-SDR (RTL2832)
>>>>>>> Note 2:
>>>>>>> Link for using RTL-SDR with GRC:
>>>>>>> http://www.instructables.com/id/RTL-SDR-FM-radio-receiver-
>>>>>>> with-GNU-Radio-Companion/?ALLSTEPS
>>>>>>> Link for using HackRF with GRC: Mike's lesson 1
>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> HackRF-dev mailing list
>>>>>>> HackRF-dev at greatscottgadgets.com
>>>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>>>>
>>>>>>>
>>>>>> _______________________________________________
>>>>>> HackRF-dev mailing list
>>>>>> HackRF-dev at greatscottgadgets.com
>>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>>>
>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> HackRF-dev mailing list
>>>>> HackRF-dev at greatscottgadgets.com
>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>>
>>>>>
>>>>
>>>
>>
>
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