osmocom-sdr

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912 discussions

Re: fl2k output voltage level changes every few seconds
by Ioannis Makris 24 May '19

24 May '19

While this is truly unexpected behaviour, please understand that the device was designed for a termination load of 75+j0 ohms (that's what all video/VGA analog signals require to be present at the load side) so any other load impedance value is untested at factory. I have independently tested that shorting the output to the ground causes an instant halt to the output of the plain VGA dongle, so there might be some protection circuit. Also, the VGA circuit has 150 ohms termination loads.

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gr-osmosdr yml file for gnuradio/grc/blocks
by Steven Barbo 23 May '19

23 May '19

Hello. Managed to compile gr-osmosdr from git with gnuradio 3.8tech-preview-365-gd66bc948 (Python 3.7.3) Having some issue converting osmosdr-source and sink block files from xml verion to yml. Anyone done such they'd be willing to share? Thank you. -- If something is requisite, how can it possibly be, prerequisite? vanitas vanitatum omnia vanitas later, steve http://umn.edu/~barbo

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fl2k output voltage level changes every few seconds
by Daniel Correa 03 May '19

03 May '19

Hi. When running the command line fl2k_fm -c 5000 /dev/zero to generate a continuous wave, the output voltage of the fl2k dongle regularly switches between two different amplitude levels (peak to peak voltage) every 2 or 3 seconds, by about %30 to %70 depending on the load. There's no visible gradual transition, it just switches instantly. The output peak-to-peak voltage is about 350 milivolts with no load. I've calculated the output impedance to be about 750 ohm at that frequency for the larger output level. I'm using the HDMI version of the dongle with the wire soldered after a capacitor (or resistor maybe) which was already there, to the red VGA pixel output of the chip. Could the issue be because some signal conditioning circuitry is missing that is present in the actual VGA version of the dongle, or that the pin is actually pulled to ground in this dongle as it is unused, and the chip doesn't like it and for some reason it then decides to regularly switch voltages? Any other ideas?

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License
by Richard Frye 17 Apr '19

17 Apr '19

If I write software that uses the rtlsdr library that is already installed on the computer, does my software also have to be opensource? Thanks, Richard

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MacOS Sierra Support
by Setzero 14 Apr '19

14 Apr '19

Hi all I am trying to use osmocom fl2k in my macbook pro. I have compiled the software but when I plugged the new falcon 2000 base usb3 to vga adapter I am not getting that in USB list. Please guide me , should i need any specific driver? And the next steps Thank you

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Use of the rtl-sdr library
by GUERINOT, Justin 01 Apr '19

01 Apr '19

Hello, I am trying to develop a simple application using rtlsdr's library functions as simple as rtlsdr_get_device_count(). But, at the moment of compilation GCC is unable to find the reference to the function and exit the errors : « Undefinded reference to the function rtlsdr_get_device_count() ; » « ld returned 1 exit status » My code is below : #include <stdio.h> #include <stdlib.h> #include «/usr/include/rtl-sdr.h » int main(int argc, char *argv[]) { int device_count ; device_count = rtlsdr_get_device_count() ; printf(« Device ID : %d », device_count) ; return 0 ; } That sounds normal because source code and headers files are dispatched in different files and not compiled. A solution would be to copy each headers, each sources together and compile them. But it should take a lot of times... It should exists another solution but I don't find it. For example, in the acarsdec software, how the developer was able to compile his software ? I hope I well explained my issue, Thank you in advance for your help Best regards, ____________________________________________________________________ Justin Guérinot Intern | Capgemini Digital Engineering & Manufacturing Services Capgemini France | Toulouse Mob.: + 33 6 33 77 14 32 www.capgemini.com<http://www.capgemini.com/> [https://visualidentity.capgemini.com/capgemini.png] ____________________________________________________________________ Connect with Capgemini: [cid:image002.png@01D41855.E5D1B680]<https://www.capgemini.com/insights-and-resources/blogs>[cid:image003.png@01D41855.E5D1B680]<https://www.twitter.com/capgemini> [cid:image004.png@01D41855.E5D1B680] <https://www.facebook.com/capgemini> [cid:image005.png@01D41855.E5D1B680] <https://www.linkedin.com/company/capgemini> [cid:image006.png@01D41855.E5D1B680] <https://www.youtube.com/capgeminimedia> [cid:image007.png@01D41855.E5D1B680] <https://www.slideshare.net/capgemini> [cid:image009.png@01D41855.E5D1B680] <https://plus.google.com/+CapgeminiGlobal> Please consider the environment and do not print this email unless absolutely necessary. Capgemini encourages environmental awareness. This message contains information that may be privileged or confidential and is the property of the Capgemini Group. It is intended only for the person to whom it is addressed. If you are not the intended recipient, you are not authorized to read, print, retain, copy, disseminate, distribute, or use this message or any part thereof. If you receive this message in error, please notify the sender immediately and delete all copies of this message.

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Writing a Stand Alone Program Using GNURadio Blocks/Components
by P C 06 Mar '19

06 Mar '19

This is my first post and I have been experimenting with an rtl-sdr for only a few weeks. So I am sure I am not doing a lot of things correctly. But: I have created a GRC flow graph that does what I want. It has a rtl-sdr>FIR filter> I/Q samples> file. I need to create a stand alone program that when run, implements the same functions but rather then sending the samples to a file, passes them to my program for further processing. I intend to run it on a Raspberry Pi so the less overhead the better. Thanks In Advance. Pete

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Bus error using rtl-sdr
by Amin Shah Gilani 13 Feb '19

13 Feb '19

Hi I'm experiencing a "bus error" everytime rtl-sdr tries to interact with my SDR. Here's a sample: rtl_fm -f 1000000 Found 1 device(s): 0: Realtek, RTL2838UHIDIR, SN: 00000001 Using device 0: Generic RTL2832U OEM Found Rafael Micro R820T tuner Tuner gain set to automatic. [R82XX] PLL not locked! Tuned to 1252000 Hz. Oversampling input by: 42x. Oversampling output by: 1x. Buffer size: 8.13ms Exact sample rate is: 1008000.009613 Hz Allocating 15 zero-copy buffers Bus error I'm running Kali on a Raspberry Pi, and I've used the repository version, and compiled from source — no change. The only thing that makes this error go away in `rtl_test` is to pass it the -S flag (forcing synchronous) flow. Does anyone have any idea how to fix this? If you'd like the Karma and would like to help solve this problem publicly for future users, Stack Overflow question continuously being updated is here: https://stackoverflow.com/questions/54657089/rtl-sdr-crashes-with-bus-error… ―Amin Shah Gilani <https://amin.gilani.me/>

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FL2K replace MT34TL/AS11D buck chip with LDO
by Ioannis Makris 09 Feb '19

09 Feb '19

I have managed to replace both buck DC-DC converters with AMS1117 3.3 & lm317 linear regulators and I successfully got rid of the mentioned 1 MHz buck converter clock to obtain as pure a signal as possible. Do not expect miracles as the DAC's are 8-bit and have a best case SNR of -48dB, but getting the sideband modulation out of the signal surely improves the resulting spectrum a lot. I have performed the mod on 4 fl2k adapters. Two of them came with a 1.2V AMS1117 for the 1.2V and a buck psu for the 3.3V. Another two came with 2 buck psu's Using 2 LM317 is a bit complex but can be done, as my proof of concept testbed has demostrated. One could actually fit them inside the plastic box. Mind you, linear regulators can get quite hot. Still not hot enough to inflict any damage after a 8-hour operation of the device. Another notable effect was the total elimination of "cb status 1" message on the testbed. The testbed suffered a lot of USB connection drops due to poor power delivery to the chip, which is also the plague of those devices that is causing bad reviews along with the poor assembly of the cable from those that use the device in regular vga output mode. The workaround is extremely simple; we use the onboard capacitors for filtering the output of the linear regulators, I install them inverted and add metal pins from 1/4W resistors to patch the power from the pin of the buck chip to the input of the linear regulator. Same with ground. Of course we are using USB3 interface that can provide more than 2.5W (500mA) of output power. I haven't thorougly tested device operation and stability under USB2.0 which has the aforementioned power limiting. The device looks stable though. There are implementations utilizing a pair of AMS1117 from factory. [image: 20190125_194224_001.jpg]

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FL2K replace MT34TL/AS11D buck chip with LDO
by matthew quirke 09 Feb '19

09 Feb '19

Has anyone tried replacing the MT34TL/AS11D buck converter/supply chip with a LDO regulator as Steve Markgraf suggested - my goal is to remove the harmonics, for HF tx. The MT34TL/AS11D(xx) datasheet is available online so it seems very do- able - just considering all the pitfalls - issues/ obvious things I missed ;) Any input/advice is much appreciated. -Matt

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