Re: Gnuradio for Raspberry PI 4 and SDRPLay works well, but need documentation

[Glen I Langston]

Hi Marcus,

Two good things about the SDRplay, now that the gnuradio interface seems
to be working, are:

1) Very high gain.   I need about 30 dB of IF attenuation to get the levels 
right.
2) Very good data transfer rates.   Right now I appear to be getting 100% of 
the 7 MHz samples
delivered to a raspberry Pi 4 and/or Odroid n2.

I’ve not yet fully checked the SDRPlay for short term transients.

Note that the Pluto SDR has no (or at least few) short term transients in the 
RF.
I did find the AIRSPY did have some transients that seem to be due to the 
device.
These occur a few thousand times a day, but for shorter than 100 micro seconds.
Total time on is less than a second a day.

I’ll try to do another calibration test.  My initial test seemed to show 
significant gain changes
across the 7MHz band, as if I have the wrong filter selected.   At one end the 
Tsys was too
low and at the other end the Tsys was too high, with a reasonable value of 
about 100 K
in the middle of the 1420 MHz band.

Still trying to figure this out. 

Best regards

Glen





> On Nov 15, 2019, at 11:56 AM, Marcus D. Leech <address@hidden> wrote:
> 
> On 11/15/2019 09:17 AM, Glen I Langston wrote:
>> Thank for your help Chris,
>> 
>> I have now gotten the SDRPlay connected to my telescope
>> and the results are looking reasonable.
>> 
>> My initial problems were with the sense of the gain values, which
>> are actually attenuation values for the SDRPlay.
>> 
>> It seems like the defaults are reasonable, and that probably
>> the correct band pass filter is being chosen for the
>> observing frequency of 1420.4 MHz.
>> 
>> I still do not fully know what the LNA slider value does.
>> 
>> FYI the initial interfering lines seem to have gone away after
>> I got sufficiently strong signals into the SDRPlay.
>> 
>> Best regards
>> 
>> Glen
> Glen:
> 
> I'm keen to learn of your progress on this.  I bought a couple of the 
> much-cheaper "clones", and I have them working, but haven't tried any
>  astronomy with them yet.
> 
> Cheers
> Marcus
> 
>>> On Nov 14, 2019, at 2:57 PM, Chris Vine <address@hidden> wrote:
>>> 
>>> On Thu, 14 Nov 2019 19:35:13 +0000
>>> Chris Vine <address@hidden> wrote:
>>>> The original poster can get some information from installing soapy and
>>>> doing 'SoapySDRUtil --probe'.
>>> I should probably have appended what the probe tells me about my RSP1A,
>>> which may or may not apply to his:
>>> 
>>> ----------------------------------------------------
>>> -- Device identification
>>> ----------------------------------------------------
>>>  driver=SDRplay
>>>  hardware=RSP1A
>>>  mir_sdr_api_version=2.130000
>>>  mir_sdr_hw_version=255
>>>  serial=xxxxxxxxxxx
>>> 
>>> ----------------------------------------------------
>>> -- Peripheral summary
>>> ----------------------------------------------------
>>>  Channels: 1 Rx, 0 Tx
>>>  Timestamps: NO
>>>  Other Settings:
>>>     * RF Gain Select - RF Gain Select
>>>       [key=rfgain_sel, default=4, type=string, options=(0, 1, 2, 3, 4, 5, 
>>> 6, 7, 8, 9)]
>>>     * IF Mode - IF frequency in kHz
>>>       [key=if_mode, default=Zero-IF, type=string, options=(Zero-IF, 450kHz, 
>>> 1620kHz, 2048kHz)]
>>>     * IQ Correction - IQ Correction Control
>>>       [key=iqcorr_ctrl, default=true, type=bool]
>>>     * AGC Setpoint - AGC Setpoint (dBfs)
>>>       [key=agc_setpoint, default=-30, type=int, range=[-60, 0]]
>>>     * BiasT Enable - BiasT Control
>>>       [key=biasT_ctrl, default=true, type=bool]
>>>     * RfNotch Enable - RF Notch Filter Control
>>>       [key=rfnotch_ctrl, default=true, type=bool]
>>>     * DabNotch Enable - DAB Notch Filter Control
>>>       [key=dabnotch_ctrl, default=true, type=bool]
>>> 
>>> ----------------------------------------------------
>>> -- RX Channel 0
>>> ----------------------------------------------------
>>>  Full-duplex: NO
>>>  Supports AGC: YES
>>>  Stream formats: CS16, CF32
>>>  Native format: CS16 [full-scale=32767]
>>>  Antennas: RX
>>>  Corrections: DC removal
>>>  Full gain range: [0, 48] dB
>>>    IFGR gain range: [20, 59] dB
>>>    RFGR gain range: [0, 9] dB
>>>  Full freq range: [0.01, 2000] MHz
>>>    RF freq range: [0.01, 2000] MHz
>>>    CORR freq range:  MHz
>>>  Sample rates: 0.25, 0.5, 1, 2, 2.048, 6, 7, 8, 9, 10 MSps
>>>  Filter bandwidths: 0.2, 0.3, 0.6, 1.536, 5, 6, 7, 8 MHz
>>> 
>> 
> 
>