Tagged: sdr#

The Panoradio: A tech-demo for direct sampling SDR

SDR researcher Stefan Scholl (DC9ST) recently wrote in to us and wanted to share his project which is a direct sampling SDR using a fast AD converter on the Zynq SoC (System on Chip). He calls the SDR ‘Panoradio’. He writes:

The Panoradio is a modern software defined radio receiver, that directly samples the antenna signal with 250 MHz with an analog-to-digital converter. The receiver captures and displays signals from 0-100 MHz, i.e. shortwave and VHF signals simultaneously, and can even receive signals from the 70 cm band with undersampling.

The hardware platform is the Zedboard, that features the Xilinx Zynq Soc, which combines an FPGA with an ARM A9 dual core and runs a Linux operating system. Fast signal processing is then done in the FPGA, slow signal processing with the ARM A9. The radio can operate in standalone mode with just a monitor and mouse attached.

The radio’s features at a glance:
– 0 -100 MHz direct sampling reception
– Direct sampling of 70 cm (425 – 440 MHz) signals
– Three independent zoomable waterfall displays (100 MHz to 6.1 kHz bandwidth)
– Two independent audio receivers (22 kHz bandwidth) with Weaver SSB demod
– Standalone operation with embedded system (Zynq / Zedboard)
– Full Linux running, including demodulation software (e.g. Fldigi)

The Panoradio is designed as a tech-demo for software defined radio, that shows what is possible with today’s technology in AD conversion and signal processing platforms.
It is an open source project, the design files can be accessed from the project website, which also includes basic information on direct sampling SDRs and single-sideband (SSB) detection:
www.panoradio-sdr.de

Stefan also presented his work at the “Software Defined Radio Academy” conferences in Friedrichshafen, Germany in both 2015 and 2016. The talks are shown below, as well as some photos and screenshots of the SDR in action.

https://www.youtube.com/watch?v=M1_fOYEi-p8
https://www.youtube.com/watch?v=HICY3TYsp9Y

A direct sampling SDR is an SDR without any analogue tuner on the front end, basically directly sampling with the ADC from the antenna. This takes us closer to a ‘true’ SDR which has very little analogue components. Over time we should start to see more direct sampling SDRs popping up. For example recently we saw the release of a new Xilinx RFSoC which is capable of sampling at up to 4Gsamples per second which should provide a very wide band, wide frequency range SDR. While this chip will probably be extremely expensive for the time being as it is mainly designed for commercial cell tower communications, it shows how well direct sampling technology is progressing.

The Panoradio: A tech-demo for direct sampling SDR

SDR researcher Stefan Scholl (DC9ST) recently wrote in to us and wanted to share his project which is a direct sampling SDR using a fast AD converter on the Zynq SoC (System on Chip). He calls the SDR ‘Panoradio’. He writes:

The Panoradio is a modern software defined radio receiver, that directly samples the antenna signal with 250 MHz with an analog-to-digital converter. The receiver captures and displays signals from 0-100 MHz, i.e. shortwave and VHF signals simultaneously, and can even receive signals from the 70 cm band with undersampling.

The hardware platform is the Zedboard, that features the Xilinx Zynq Soc, which combines an FPGA with an ARM A9 dual core and runs a Linux operating system. Fast signal processing is then done in the FPGA, slow signal processing with the ARM A9. The radio can operate in standalone mode with just a monitor and mouse attached.

The radio’s features at a glance:
– 0 -100 MHz direct sampling reception
– Direct sampling of 70 cm (425 – 440 MHz) signals
– Three independent zoomable waterfall displays (100 MHz to 6.1 kHz bandwidth)
– Two independent audio receivers (22 kHz bandwidth) with Weaver SSB demod
– Standalone operation with embedded system (Zynq / Zedboard)
– Full Linux running, including demodulation software (e.g. Fldigi)

The Panoradio is designed as a tech-demo for software defined radio, that shows what is possible with today’s technology in AD conversion and signal processing platforms.
It is an open source project, the design files can be accessed from the project website, which also includes basic information on direct sampling SDRs and single-sideband (SSB) detection:
www.panoradio-sdr.de

Stefan also presented his work at the “Software Defined Radio Academy” conferences in Friedrichshafen, Germany in both 2015 and 2016. The talks are shown below, as well as some photos and screenshots of the SDR in action.

https://www.youtube.com/watch?v=M1_fOYEi-p8
https://www.youtube.com/watch?v=HICY3TYsp9Y

A direct sampling SDR is an SDR without any analogue tuner on the front end, basically directly sampling with the ADC from the antenna. This takes us closer to a ‘true’ SDR which has very little analogue components. Over time we should start to see more direct sampling SDRs popping up. For example recently we saw the release of a new Xilinx RFSoC which is capable of sampling at up to 4Gsamples per second which should provide a very wide band, wide frequency range SDR. While this chip will probably be extremely expensive for the time being as it is mainly designed for commercial cell tower communications, it shows how well direct sampling technology is progressing.

New SDR# Plugin: Radio-Sky Spectrograph Data Stream

Edit: If you downloaded an older version of the plugin please note that it has now been updated. The update fixes some stability issues which would previously hang SDR#. The updated .dll file can be downloaded directly from https://goo.gl/VQlH9E.

Radio-Sky Spectrograph is a radio astronomy software program which is often used together with the RTL-SDR or other similar SDRs. It is best explained by the author:

Radio-Sky Spectrograph displays a waterfall spectrum. It is not so different from other programs that produce these displays except that it saves the spectra at a manageable data rate and provides channel widths that are consistent with many natural radio signal bandwidths. For terrestrial , solar flare, Jupiter decametric, or emission/absorption observations you might want to use RSS.

Usually to interface an RTL-SDR with Radio-Sky Specrtograph a program called RTL-Bridge is used. However, now SDR# plugin programmer Alan Duffy has created a new plugin that allows SDR# to interface with Radio-Sky Spectrograph via a network stream. This allows it to work with any SDR that is supported by SDR# plugins. Alan Duffy writes:

I wrote the plugin after becoming interested in amateur radio astronomy. The plugin allows you to use any of the software defined radios supported by SDR# to feed the Radio-Sky Spectrograph program with wide-band data. The plugin shows the frequency, bandwidth, and FFT resolution and has a user selected “Number of Channels” that are sent to the spectrograph program with an allowable range of 100 to 500. This number can only be edited when the data stream is not enabled. Also if certain key parameters change, such as the frequency or decimation, the network stream will stop as the spectrograph would no longer be capturing the same data. If this happens, simply click the start button on client side software (i.e. Radio-Sky Spectrograph). As long as the Enable box is checked on the server side, the plugin will listen for a connection and start transmitting data after RSS makes a new request for data.

We note that the software might also be useful for simply capturing a long term waterfall for finding active frequencies or looking for meteor scatter or aircraft scatter echoes. 

The Radio-Sky Spectrograph SDR# Plugin
The Radio-Sky Spectrograph SDR# Plugin

New SDR# Audio Waterfall Plugin

The old audio waterfall plugin for SDR# seems to be no longer available for download anywhere (it may have gone out of date and is no longer compatible with the latest versions of SDR#). Alan Duffy decided to write his own version of the audio waterfall plugin and make it available for download. An audio waterfall shows the demodulated audio in waterfall form, essentially creating an audio spectrum analyzer. This can be useful for understanding the demodulated frequency structure of a signal.

To install the plugin simply download the dll from his website and place it in the SDR# folder. Note that for us Chrome detected this file as malicious, but this is a false alarm as Chrome does this often with unknown .dll files. To recover the file we had to go to the Chrome menu -> Downloads, then select “Recover File” to download the file. (If you still have problems with the download then check out the comments as some users have kindly mirrored it). Then open plugins.xml file with a text editor, and add the magicline specified on his page.

Audio waterfall with the built in audio spectrum analyzer.
Alan’s Audio waterfall shown together with the built in audio spectrum analyzer in SDR#.

Building a Software Defined Radio from Scratch

Over on his blog Lukas Lao Beyer has uploaded a post that shows his journey with designing and building a software defined radio from scratch. Lukas’ finished SDR design is called the FreeSRP and is based on the Analog Deviced AD9364 transceiver and a Xlinx FPGA.

In his post Lukas describes how he designed the PCB with Altium Designer, routing the traces carefully to ensure the shortest path was used, and to ensure impedance matching was correct. Then after producing the PCB’s with OSH park he writes how he assembled the board by carefully placing the components down by hand and using his reflow oven. This was no easy task due to the manual nature of the operation and the high possibility for undetectable solder problems to arise. Despite the difficulties he found that the SDR powered up as expected.

His next steps were to start work on the FPGA controller design, however he discovered that he had failed to properly route some clock pins on the FPGA. On his third revision of the PCB he was able to fix this. Finally he was able to program the FPGA and get his SDR to work.

Designing an SDR from scratch is no easy task, especially if you have little design experience like Lukas did. However, in the end despite some mistakes he was able to build a working SDR that interfaces with GNU Radio. 

Lukas' FreeSRP SDR.
Lukas’ FreeSRP SDR.

Demonstrating the IF Processor and Notch Filter Plugin in SDR#

Over on YouTube user  FMDX HUN (Luc1f3rk0) has uploaded a video showing how useful the SDR# IF Processor and Notch Filter Plugin can be when attempting to DX FM broadcast stations. He shows that it can be used to listen to stations that are almost overlapping by cutting out the unwanted signal.

The plugin itself can be downloaded from http://rtl-sdr.ru/page/para-novyh-plaginov.

https://www.youtube.com/watch?v=45JEeSGvK_w

Building a Tuning Knob for SDR#

If you love using SDR’s on the PC but miss the old feeling of tuning the frequency with a knob then 19max63 has a solution for you. On his blog he’s posted about how he built his own tuning knob by using a USB mouse PCB circuit and replacing the mouse wheel with a rotary encoder with no detents. Detents are the little clicks or steps that you can feel in some knobs, but for accurate frequency tuning you don’t want those.

His post shows the exact parts he bought (knob, mouse, buttons), the mods he made to the knob and mouse PCB, and how he put it all together. He writes that parts can all be found cheaply on eBay or Aliexpress and the total cost to produce a single knob was only about $4 (though he had to buy some parts in lots of 5 to 10).

The finished tuning kob for RTL-SDR and SDR#.
The finished tuning kob for RTL-SDR and SDR#.

HamRadioScience Reviews the Elad FDM-DUO Software Defined Transceiver

The Elad FDM-DUO is a high end $1149 USD Italian made software defined radio transceiver (transmit and receiver) with a frequency range of 10 kHz – 54 MHz, a 16-bit ADC, a bandwidth of up to 6 MHz and can transmit with up to 5 – 8 watts. It is a product targeted at ham radio enthusiasts who want a gradual transition into software defined radios. It can work in two modes: either as a standalone computer-less radio just like a regular hardware radio, or as a fully functional computer based SDR.

The front of the FDM-DUO.
The front of the FDM-DUO.

Recently the admin of hamradioscience.com rather comprehensively reviewed the Elad FDM-DUO. His thoughts are that it is the perfect radio for those wanting to be slowly eased into the SDR world due to it’s dual mode operation. He writes:

The Italian made FDM-DUO has to be the most versatile, well designed, and well thought out SDR system currently on the market.

The review by hamradioscience goes over several points such as explaining what all the connectors on the radio are for, reviewing the ergonomics, reviewing the radio in standalone mode and in PC based SDR mode and he also reviews the companion software package. The reviewer is especially impressed with the included software, basically making the point that this system is a full SDR transceiver package (all you need in terms of hardware AND software).

Generally we recommend more general purpose and lower cost wideband VHF/UHF SDR’s like the Airspy, SDRplay RSP or HackRF (see our review on those SDRs here), but if you are not limited by budget and want to use an SDR mostly for HF amateur radio purposes then the Elad FDM-DUO looks like a winner. The author concludes with the following comment.

Elad got so many things right with the FDM-DUO that it is hard find much to criticize. Unlike so many SDR systems available today, the FDM-DUO SDR system feels like less of a “science project” and more of a finished consumer product. For those who wants a SDR radio system that “just works” and easy to use, the FDM-DUO is a great choice. Also, kudos to Elad for providing such a well done SDR program. The program was very stable over the review period. No, crashing at just the wrong time say during a contest. Heck even if it did, it wouldn’t matter much since you could just continue on using the FDM-DUO as a standalone rig. With some of the larger radio manufacturers dipping their toes in the SDR area, they should take note of what Elad has done with the FDM-DUO. Elad has truly created a very flexible multi-use system with the FDM-DUO and a darn fine SDR radio system at a very good value.

FDMDuo_SW
The Elad FDM software package.

New Version of the Frequency Manager Suite Plugin for SDR# Released

Recently the commonly used Frequency Manager Suite Plugin for SDR# has been updated. The plugin suite works well with the RTL-SDR and includes features such as a frequency scanner and manager, a scanner metrics recorder, a scheduler, an activity logger and a frequency entry plugin. The changelog is shown below:

Frequency Manager + Scanner

  • New feature: you may now optionally display the descriptions of frequencies in your database on the spectrum window. You control the colors and transparency of the descriptions and their marker lines. 
  • New feature: the Browse window now allows you to type a frequency directly into the grid, and the grid will dynamically filter your database to matching frequencies. You may type a partial frequency and all frequencies that start with the same digits will be displayed. The more digits you type, the more specific the filtering.
  • New feature: A checkbox in Preferences lets you control whether the Last Update field is changed when performing bulk edits. When unchecked this permits you to retain the original date and time the frequency was recorded in the database. 
  • New feature: You may now change the font size in the Scanner Decisions window and plugin. The new size will be remembered and used the next time you start SDR#. 
  • New article:  User David Bunyan has provided a how-to article in the Appendix on how to use the scanner effectively for WFM DXing.  See also the WFM DXing Databases download in the Download Here section to get pre-built databases for different regions around the world, also graciously provided by David Bunyan.

Scanner Metrics

  • Bug fix: fixed error in the queue manager that prevented recording activity when the date-time format on the computer was not United States. 
  • Bug fix: fixed error that prevented SM from putting its database in the same folder as FM, if the FM database location was changed after SM was loaded.

Data Tools

  • New feature: default values for imports. Will automatically assign values when they are missing from the source import data.
  • Bug fix: Fixed culture-specific issue with Frequency values when an Eibi database is downloaded. 
  • Bug fix: Fixed bug that caused Data Tools to change the current database in Frequency Manager + Scanner. 
  • Bug fix: Importing an SDR# Frequency Manager data file now results in a prompt to add or replace existing data in the target FMSuite database.

The Pluginator

  • New feature: The Pluginator now knows many of the most popular plugins. So now you may simply select one from a list and it will be installed to Plugins.xml, as opposed to requiring you to type the configuration data for the chosen plugin.

FreqMgr