Hi Tavi, It would be best to use an SDR or a board like Redpitaya or SNAP that can sample the entire band, but if you have got an RTLSDR, I can suggest a small trick that might work (no harm in trying). GQRX might be an overkill as you don't need the demodulation part. I have written a small python code that uses pyrtlsdr to read some samples and FFT them. The centre frequency is changed and the process is repeated. The spectra are then stitched together. The code snippet is not the best and the logic has got some bugs. Nonetheless, you can start from that and develop. It is available at [ https://github.com/VU3VWB/rtlsdr_spec_analyser | https://github.com/VU3VWB/rtlsdr_spec_analyser ] ; try rtl_spec_analyser_fft_scan_3.py
NB: This is my first time replying to a mailing list, please let me know if there is some silly mistake (reply, reply to all etc.) Regards, Jishnu From: "Tavi B" <[email protected]> To: [email protected] Sent: Thursday, 14 November, 2019 08:17:31 Subject: Re: [casper] heliospectroscope Hello, Dan, Thank you very much for your detailed answer. I will read the details of suggested boards. So far I've try RTL-SDR, Airspy2+Spywerter and bladeRF x40+XB200 with gqrx. But the gqrx cannot sweep and record full bandwidth at needed sample rate. The main concern is the time of stabilization of the frequency tuned, that's why a large simultaneous bandwidth is desired. The bladeRF 2.0 is faster and have a large bandwidth (56MHz) and have affordable price. It is an integrated radio with TX and filters but we would not pay for features that we don't need. RedPitaya sounds better. Best regards, Octavian marți, 12 noiembrie 2019, 16:13:51 UTC+2, danseti a scris: hi octavian, i don't know much about solar radio spectroscopy, but i think in some solar applications, the SNR is very high, and the time variability is slow enough that you could use a spectrometer with a small instantaneous bandwidth, perhaps 10 or 20 MHz bandwidth, and then sweep this spectrometer across your 800 MHz band. if that's the case, the spectrometer could be very inexpensive because you could use a GNUradio system. if you need more instantaneous bandwidth, the red pitaya fpga board has two 125 Msps ADC's, and casper has a spectrometer tutorial for this board. you might be able to use the spectrometer tutorial design directly, or modify the design for your application. the red pitaya boards cost a few hundred dollars. [ https://www.redpitaya.com/f130/STEMlab-board | https://www.redpitaya.com/f130/STEMlab-board ] the next step up would be to use a snap fpga board, which costs about $3000, and has four 950 Msps ADC's. casper has a spectrometer tutorial for the snap board as well. for even higher instantaneous bandwidth, there are several casper ADC boards you could plug into the snap board. eg: single 2 Gsps ADC board, a dual 2.5 Gsps ADC board.... information on the snap board, adc boards and tutorials are on the casper wiki pages. best wishes, dan Dan Werthimer Marilyn and Watson Alberts Chair Astronomy Dept and Space Sciences Lab University of California, Berkeley On Tue, Nov 12, 2019 at 1:27 AM Tavi B < [ javascript-blocked: | [email protected] ] > wrote: BQ_BEGIN Hello, I'm new in this research, in Romania there is no scientific radio telescope yet. I'm working at the Solar Group of Astronomical Institute of Romanian Academy and this is the reason I would start with a solar radio spectroscope, CALLISTO like station. I searched an inexpensive SDR to emulate the callisto analog receiver but with fairly large bandwidth and speed. The high end ones are too expensive and have many features that we don't need like DAC, TX, filters and so on. I've learned that a 12bit ADC with high Mbsp and a FPGA can do the job, we don't need to decode or demodulate a signal, just record the noise level coming from the Sun (or other radio astronomy objects). In this search I've found your group and I wonder if you can help me to find a really cheap solution because we don't have a budget for this project right now. What modules I can buy or build myself (I have basic skills on electronics, microcontrollers and radio) to get a spectrogram of 400 MHz wide with a better than 0.1s time resolution? The Sun radio burst can be received between 10-1500MHz but with different antennas, so I would start with a log periodic dipole wide band antenna, from 120 to 800MHz. Thank you and best regards, Octavian Blagoi researcher AIRA [ http://www.astro.ro/ | www.astro.ro ] -- You received this message because you are subscribed to the Google Groups " [ javascript-blocked: | [email protected] ] " group. To unsubscribe from this group and stop receiving emails from it, send an email to [ javascript-blocked: | [email protected] ] . To view this discussion on the web visit [ https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/68ef8ced-7318-436d-b1fd-a96db187122f%40lists.berkeley.edu?utm_medium=email&utm_source=footer | https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/68ef8ced-7318-436d-b1fd-a96db187122f%40lists.berkeley.edu ] . BQ_END -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [ mailto:[email protected] | [email protected] ] . To view this discussion on the web visit [ https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/f8a45127-569f-4467-a468-0afe53a625f9%40lists.berkeley.edu?utm_medium=email&utm_source=footer | https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/f8a45127-569f-4467-a468-0afe53a625f9%40lists.berkeley.edu ] . -- You received this message because you are subscribed to the Google Groups "[email protected]" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/a/lists.berkeley.edu/d/msgid/casper/1969367094.1121821.1574155414399.JavaMail.zimbra%40rri.res.in.
