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

Mehdi Asgari mehdi.qbic at gmail.com
Mon Sep 22 11:00:31 EDT 2014


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
>>>>
>>>>
>>>> _______________________________________________
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>>>> HackRF-dev at greatscottgadgets.com
>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>
>>>>
>>> _______________________________________________
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>>> HackRF-dev at greatscottgadgets.com
>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>
>>
>>
>> _______________________________________________
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>>
>>
>
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