[Hackrf-dev] how to set IF in GNU Radio for HackRF

[Karl Koscher]

Try specifying a receive frequency of 1.575 GHz with hackrf_transfer and
tell matlab your IF is 420 kHz. The sum of the two frequencies is 1.57542
GHz, which is the L1 GPS frequency.

On Thu, Nov 19, 2015 at 2:44 PM, mourad ghafiri <mourad.ghafiri at gmail.com>
wrote:

> even I need the IF it in the matlab project :) , so what value I should
> put there, I will experiment the hackrf_transfer program and see to what
> extent I will get the desired results.. and for sure I will share my
> results with you and for the hackrf community as a contribution for GPS
> signal decoding, if I do it myself :)
>
> On Thu, Nov 19, 2015 at 10:40 PM, Karl Koscher <supersat at cs.washington.edu
> > wrote:
>
>> Just specify the frequency you want to tune to with -f. You shouldn't
>> need to specify -i.
>>
>> On Thu, Nov 19, 2015 at 2:29 PM, mourad ghafiri <mourad.ghafiri at gmail.com
>> > wrote:
>>
>>> @Karl Koscher
>>>
>>> I used the Gnu radio, I will use the hackrf_transfer , but please would
>>> you help for IF parameter
>>> [-i if_freq_hz] # Intermediate Frequency (IF) in Hz [2150MHz to 2750MHz]
>>> ?
>>>
>>> I don't know what to set for IF since I need to tune hackrf at 1.575 GHz
>>> and Bandwidth of 2 MHz and a sampling rate > 2*2 MHz
>>>
>>> would you give me a complete command for these requirements,
>>>
>>> Thank you so much in advance
>>>
>>> Regards;
>>>
>>>
>>> On Thu, Nov 19, 2015 at 10:22 PM, Karl Koscher <
>>> supersat at cs.washington.edu> wrote:
>>>
>>>> How doesn't it work? You should probably just use the hackrf_transfer
>>>> program to record data from the HackRF. By default, it stores data in
>>>> complex int8 format.
>>>>
>>>> On Thu, Nov 19, 2015 at 2:18 PM, mourad ghafiri <
>>>> mourad.ghafiri at gmail.com> wrote:
>>>>
>>>>> @Karl Koscher
>>>>>
>>>>> unfortunately the approach doesn't function well... please any hint to
>>>>> achieve that  goal which is:
>>>>>
>>>>> having an GPS L1 signal streaming for post processing with
>>>>> matlab/octave ? we have HackRF and a GPS L1 antenna ... but we don't have
>>>>> enough knowledge in hardware side, but we do know how to manipulate a file
>>>>> streaming with float or int8 matrix data in Matlab/octave.
>>>>>
>>>>> Yours Sincerely;
>>>>>
>>>>> On Thu, Nov 19, 2015 at 10:11 PM, mourad ghafiri <
>>>>> mourad.ghafiri at gmail.com> wrote:
>>>>>
>>>>>> @David Brown
>>>>>>
>>>>>> I appreciate your interaction with that basic question, in fact we
>>>>>> are recording a L1 GPS streaming for post processing in a Matlab project
>>>>>> for GPS positioning... so all we need simply is a file that contain an int8
>>>>>> type record.
>>>>>>
>>>>>> @Karl Koscher
>>>>>>
>>>>>> thank you so much, I will try this blocks Immediately and get back to
>>>>>> you; if you still have time to complete this friendly (hackerfly :) )
>>>>>> conversation.
>>>>>>
>>>>>> On Thu, Nov 19, 2015 at 10:04 PM, Karl Koscher <
>>>>>> supersat at cs.washington.edu> wrote:
>>>>>>
>>>>>>> Use a Complex to Float/Real and Float to Char type converter block
>>>>>>> between the HackRF source block and the file sink, and then change the file
>>>>>>> sync type to char. Or you can use the hackrf_transfer program and avoid
>>>>>>> these conversions altogether.
>>>>>>>
>>>>>>> On Thu, Nov 19, 2015 at 1:49 PM, mourad ghafiri <
>>>>>>> mourad.ghafiri at gmail.com> wrote:
>>>>>>>
>>>>>>>> thank you  for your quick answer, please how to record the
>>>>>>>> streaming in int8 type
>>>>>>>>
>>>>>>>> Regards;
>>>>>>>>
>>>>>>>> On Thu, Nov 19, 2015 at 9:40 PM, Karl Koscher <
>>>>>>>> supersat at cs.washington.edu> wrote:
>>>>>>>>
>>>>>>>>> You are recording complex floats. The intermediate frequency is
>>>>>>>>> your frequency of interest minus what the HackRF is tuned to. If your
>>>>>>>>> HackRF is tuned to 1.575 GHz but you want to decode the GPS L1 signal, then
>>>>>>>>> your IF is 420 kHz.
>>>>>>>>>
>>>>>>>>> On Thu, Nov 19, 2015 at 1:36 PM, mourad ghafiri <
>>>>>>>>> mourad.ghafiri at gmail.com> wrote:
>>>>>>>>>
>>>>>>>>>> I attached the flow graph for the recording as well as a real
>>>>>>>>>> time spectrum , I'm not sure what blocks to use or what parameters to set
>>>>>>>>>> for this block in order to have the right streaming.
>>>>>>>>>> thanks for showing interest to the question
>>>>>>>>>>
>>>>>>>>>> On Thu, Nov 19, 2015 at 9:16 PM, Karl Koscher <
>>>>>>>>>> supersat at cs.washington.edu> wrote:
>>>>>>>>>>
>>>>>>>>>>> How are you recording the samples?
>>>>>>>>>>>
>>>>>>>>>>> On Thu, Nov 19, 2015 at 1:05 PM, mourad ghafiri <
>>>>>>>>>>> mourad.ghafiri at gmail.com> wrote:
>>>>>>>>>>>
>>>>>>>>>>>> Hello;
>>>>>>>>>>>>
>>>>>>>>>>>> please any help to figure out what is the Intermediate
>>>>>>>>>>>> Frequency used for HackRF in Gnuradio...
>>>>>>>>>>>>
>>>>>>>>>>>> I'm recording a streaming file for GPS and I don't know what is
>>>>>>>>>>>> the appropriate type ( int; float...) and what is the appropriate IF to use
>>>>>>>>>>>> in order to process that streaming in Matlab.
>>>>>>>>>>>>
>>>>>>>>>>>> Best Regards;
>>>>>>>>>>>>
>>>>>>>>>>>> _______________________________________________
>>>>>>>>>>>> HackRF-dev mailing list
>>>>>>>>>>>> HackRF-dev at greatscottgadgets.com
>>>>>>>>>>>> https://pairlist9.pair.net/mailman/listinfo/hackrf-dev
>>>>>>>>>>>>
>>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>
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