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

[Mehdi Asgari]

Thanks. Didn't change (tried both Mono and Stereo, tried your gain values
and a lot of other combinations)
And 20M overflows my CPU and I have to use a lower sampling rate (I've
tested from 1.5M to 16M)
My antenna is ANT500.

On Mon, Sep 22, 2014 at 7:31 PM, Mike Jameson <mike at scanoo.com> wrote:

> 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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