N1njAgam3R
Posts: 3
Joined: Mon May 20, 2013 4:29 pm

Software Defined Radio

Thu Jun 06, 2013 9:04 pm

So here's the deal guys, I've got a project I'm working on that would require the use of an USB FM Radio dongle on the Raspberry Pi. What I would like to know is if a software defined radio program for the Raspberry Pi exists or not.

Things I'm looking for in SDR:

-Waterfall graph
-The ability to log data (if not I can manage that with screenshots)
-The ability to control Nooelec DVB FM dongle

Any help would be greatly appreciated!

N1njAgam3R
Posts: 3
Joined: Mon May 20, 2013 4:29 pm

Re: Software Defined Radio

Wed Jun 12, 2013 2:23 pm

Alright, I have found RTLSDR as a possible software solution. I've gone through the steps of installing the files onto my Raspbian running Pi. However, I'm not quite sure how to use the software. Anybody with experience with this software or eager to help me figure this out would be most appreciated!

Link to the RTLSDR installation instructions: http://eartoearoak.com/software/rtlsdr- ... stallation

VE7VIE
Posts: 2
Joined: Wed Jun 26, 2013 12:10 am

Re: Software Defined Radio

Wed Jun 26, 2013 12:27 am

I'd LOVE to use the RPi to do the waterfall thing and tune my Elecraft KX3 ham radio!
VE7VIE

N1njAgam3R wrote:So here's the deal guys, I've got a project I'm working on that would require the use of an USB FM Radio dongle on the Raspberry Pi. What I would like to know is if a software defined radio program for the Raspberry Pi exists or not.

Things I'm looking for in SDR:

-Waterfall graph
-The ability to log data (if not I can manage that with screenshots)
-The ability to control Nooelec DVB FM dongle

Any help would be greatly appreciated!

User avatar
yv1hx
Posts: 372
Joined: Sat Jul 21, 2012 10:09 pm
Location: Zulia, Venezuela
Contact: Website

Re: Software Defined Radio

Tue Jul 23, 2013 3:56 pm

N1njAgam3R wrote:So here's the deal guys, I've got a project I'm working on that would require the use of an USB FM Radio dongle on the Raspberry Pi. What I would like to know is if a software defined radio program for the Raspberry Pi exists or not.

Things I'm looking for in SDR:

-Waterfall graph
-The ability to log data (if not I can manage that with screenshots)
-The ability to control Nooelec DVB FM dongle

Any help would be greatly appreciated!
Hi,

I never done this, since I don't have a SDR yet, but you could test those steps: http://zr6aic.blogspot.com/2013/02/sett ... erver.html

Also, search the forum with "RTL-SDR" ans should bring some related post, good luck! :D
Marco-Luis
Telecom Specialist (Now Available for Hire!)

http://www.meteoven.org
http://yv1hx.ddns.net
http://twitter.com/yv1hx

User avatar
Jim Manley
Posts: 1600
Joined: Thu Feb 23, 2012 8:41 pm
Location: SillyCon Valley, California, and Powell, Wyoming, USA, plus The Universe
Contact: Website

Re: Software Defined Radio

Tue Jul 23, 2013 7:41 pm

There have been a bunch of threads started on this subject over the past year, the most recent yesterday. Here's info posted most recently that may be useful:

http://jeffskinnerbox.wordpress.com/201 ... sdr-for-20

It's not completely clear, but he appears to only have attempted this on an x86 system running Ubuntu 13.04, and it took over an hour to build the GNU Radio software. While he mentions the Pi early on in the article, everything that he actually accomplished only seems to be on the x86 Ubuntu system. He wound up using already-built executables for part of his efforts, as there were insurmountable problems building from source, and that was apparently on x86 hardware, much less ARM or the Pi.

A search of this forum for "Software Defined Radio" shows at least half a dozen threads, mostly from 2012 with no obvious success on the Pi. A Google search finally found this link:

http://www.hamradioscience.com/raspberr ... l2832u-sdr

which seems to have the steps for getting an SDR running on even a 256 MB Pi on Wheezy (and therefore I assume Raspbian). However, read all of the comments to the article which show varying levels of success using various RF dongles, with the RTL2832U / E4000 dongles apparently working fine, but reportedly not so easily using the allegedly somewhat more sensitive RTL2832U / R820T models. Also note that these dongles require significant amounts of power, so a powered USB hub is a must, as even a 1 amp, 5-volt Pi supply couldn't reliably operate the Pi with the dongle plugged into a USB port. That may have been due to use of older Pi boards with polyfuses F1 and F2 on the USB power traces - forewarned is forearmed.
The best things in life aren't things ... but, a Pi comes pretty darned close! :D
"Education is not the filling of a pail, but the lighting of a fire." -- W.B. Yeats
In theory, theory & practice are the same - in practice, they aren't!!!

MikeHalliday
Posts: 9
Joined: Thu Apr 19, 2012 7:12 am

Re: Software Defined Radio

Fri Aug 09, 2013 9:51 pm

Instead of ham radio, would it be possible to use say 20 - 30 metal coat hangers strung out in 'x' formation connected to an sdr compatible USB dongle to receive outer space signals? Just like a radio telescope? I know that one of the biggest radio telescopes (Jodrell Bank) in the UK uses a parabolic dish, but I have seen radio telescopes in the USA use flat open spaces looking at the same bit of sky! Is there radio telescope software available for Linux that could be re-compiled for rPI?

I have enough garden space to have at least 20 spaced evenly on a wooden frame, but not sure if it's worth the hard work making the frame?

It would however be an awesome addition to my optical telescope setup!

User avatar
elektrknight
Posts: 140
Joined: Sat Mar 02, 2013 1:25 pm

Re: Software Defined Radio

Sat Aug 10, 2013 6:48 pm

MikeHalliday wrote:Instead of ham radio, would it be possible to use say 20 - 30 metal coat hangers strung out in 'x' formation connected to an sdr compatible USB dongle to receive outer space signals? Just like a radio telescope?
I do no know about radio telescopes but metal coat hangers make excellent HDTV antennas.
http://uhfhdtvantenna.blogspot.com/
Placek Malinowy to jest to!

User avatar
Jim Manley
Posts: 1600
Joined: Thu Feb 23, 2012 8:41 pm
Location: SillyCon Valley, California, and Powell, Wyoming, USA, plus The Universe
Contact: Website

Re: Software Defined Radio

Sun Aug 11, 2013 1:04 am

It depends on what kind of radio to which you want your telescope to be able to listen. Here's the frequencies of interest to radio astrononmy:

25.550 – 25.670 Mhz
37.5 – 38.25 Mhz
73 – 74.6 Mhz
150.05 – 153 Mhz
322 – 328.6 Mhz
406.1 – 410 Mhz
608 – 614 Mhz
1.4 – 1.427 Ghz
1.6106 – 1.6138 Ghz
1.66 – 1.67 Ghz
2.655 – 2.700 Ghz
4.8 – 5 Ghz
10.6 – 10.7 Ghz
18.28 - 18.36 GHz

Most natural cosmic sources have spectra that fall off with frequency, so even if you keep the same antenna aperture (effective area) the strength of the signals will decrease with frequency.

Consequently, the lower the frequency that is still transparent to the ionosphere (e.g. above 18Mhz), the greater the energy (signal strength) that can be collected by a specific gain of antenna. Said another way, the lower the frequency above 18 MHz, the better chance you have of detecting it.

What you gain by going up in frequency is:
- a narrower antenna beam (if you keep the same antenna area)
- less man-made interference
- more transparency to the ionosphere
- a larger possible bandwidth (if your hardware can eat it)

The relationship between gain and effective area is

G = 4 * PI * A / L2 or A = G * L2 / 4 / PI

Where G is gain (linear, not dB), A is the effective area, PI is 3.14... and L2 is wavelength squared. Units for A and L2 are not important, but both must be given in the same units. The same area means more gain at a higher frequency, and the same gain means less area at a higher frequency.

Consequently from this reasoning the best choice of frequency would then be the lowest frequency that is free of interference that can be installed on the land area available to the Amateur Radio Astronomer. Land area becomes even a greater concern with interferometry as the antenna must be spaced apart East to West by 15 or more wavelengths to achieve a suitable fringe pattern.

By following the links on http://www.hardhack.org.au/ra_frequencies, you can learn everything you need to know about building an amateur radio telescope, including antennas, receivers, techniques, frequency choices, etc.
The best things in life aren't things ... but, a Pi comes pretty darned close! :D
"Education is not the filling of a pail, but the lighting of a fire." -- W.B. Yeats
In theory, theory & practice are the same - in practice, they aren't!!!

Nige C
Posts: 46
Joined: Thu Jul 19, 2012 12:22 am
Location: Hadleigh, Suffolk

Re: Software Defined Radio

Sun Aug 11, 2013 1:20 am

I have already done this many months ago. I bought a usb TV dongle and managed to find drivers and software to run it on my Pi. My antenna was a wideband discone in the loft. In my rural location I managed to pick up some traffic. I am a radio ham I was able to pick up 2m transmissions and airplanes flying over my house. My dongle I think had an 820T chip in it. I will have to look up my notes
Retired power engineer with a lot of real life experience. Life is an adventure again :)

Nige C
Posts: 46
Joined: Thu Jul 19, 2012 12:22 am
Location: Hadleigh, Suffolk

Re: Software Defined Radio

Sun Aug 11, 2013 1:55 am

I had the waterfalls running. But the Pi would lock up if tasked too much. I also tried monitoring Airnav frequencies in the 1090 Mhz band, so called secondary radar. This worked well. But the PI was struggling.
Retired power engineer with a lot of real life experience. Life is an adventure again :)

Nige C
Posts: 46
Joined: Thu Jul 19, 2012 12:22 am
Location: Hadleigh, Suffolk

Re: Software Defined Radio

Sun Aug 11, 2013 2:14 am

Space the Final Frontier. But electromagnetically wide. It depends what you want to tune into. It's all great, and fun. I am an amateur astronomer, I follow a lot of the electromagnetic spectrum including light. Including my fibre optic connection to you, from rural Suffolk. 80 Megabits for the win :)
Retired power engineer with a lot of real life experience. Life is an adventure again :)

User avatar
Jim Manley
Posts: 1600
Joined: Thu Feb 23, 2012 8:41 pm
Location: SillyCon Valley, California, and Powell, Wyoming, USA, plus The Universe
Contact: Website

Re: Software Defined Radio

Sun Aug 11, 2013 6:24 am

Nige C wrote:I follow a lot of the electromagnetic spectrum including light
Unless you're living on top of Mauna Kea where the only ground-based infrared telescope is located, you're missing one important part of the spectrum. I'm waiting to be scheduled for flights aboard the NASA and DLR (the German version of NASA) Stratospheric Observatory For Infrared Astronomy (SOFIA) highly-modified 747SP in 2014 for NASA's Airborne Astronomy Ambassador (AAA) program. The aircraft carries a 17-ton, 10-foot diameter reflector telescope built for the DLR that peers out through a 10 x 12 foot opening to the stratosphere in flight in the port side of the fuselage, aft of the wing. A second pressure bulkhead was installed forward of the telescope, which is in the former aft end of the coach section of the former Pan Am Clipper and United Airlines airliner.

Image

The telescope is balanced on a 3-foot diameter solid steel sphere at the center of the bulkhead with a one-foot diameter optically transparent quartz Nasmith tube passing through it. There are two tertiary planar mirrors on the telescope, one with a sparse gold atom matrix where the atoms are close enough together to reflect far-infrared energy (just above the cosmic background microwave radiation from the Big Bang), but far enough apart to allow visible light wavelengths to pass through.

A second traditional aluminum-coated mirror is about 18 inches behind the first mirror due to the differences in focal length of the two wavelength ranges (those red f-stop numbers on camera lenses are the infrared values). Both energy beams pass through the Nasmith tube to up to four sensor packages positioned on the counterweight on the interior side of the bulkhead and they perform infrared or visible light imaging, spectroscopy, interferometry, energy intensity measurement, etc. About 30 sensors are planned for development over the next couple of decades that the aircraft will be flying, with improved sensitivity, accuracy, etc., as technology gets better.

Image

The AAA program is the closest thing NASA has to the Teachers in Space program that ended when teacher Christa McAuliffe died in the Space Shuttle Challenger explosion. Educators fly aboard the aircraft on collection missions that last about 8 - 10 hours overnight at 45,000 feet and assist world-class astronomers, telescope operators, and mission specialists with collection, processing, analysis, and mission track decisions. We also document the activities for our students and those all over the world via social media, which includes the years of training and preprations leading up to a flight, the missions themselves, and post-flight processing, in-depth analysis, follow-on long-term research, etc. All of the data is recorded on petabytes' worth of removable disk drives (for post-mission research) and there is a massively-parallel high-performance computing system on board that performs near-real-time image and other sensor data processing.

As data is collected and given a quick-look by the astronomers on-board, decisions are made in conjunction with the mission director at their side (who monitor aircraft navigation along the planned track) whether to continue collection or move on to lower-priority targets. Subsets of images and data are also transmitted via the NASA Tracking and Data Relay Satellites (TDRS) to researchers around the world over gigabit-per-second research internetworks so those who can't make a given flight can also make recommendations about continued target collection vs. moving on to the next target.

Image

The sphere in the bulkhead acts as a pivot point to isolate the telescope from small aircraft roll, pitch, and yaw motions, and dozens of truck air shock absorbers around the periphery of the bulkhead that are computer controlled based on multi-axis accelerometer inputs to damp out even miniscule aircraft vibrations and movements. The telescope can remain boresighted on a target the size of a dime at over a mile away, which has been verified by putting the entire aircraft on a shake table and measuring the telescope's stability.

I'll be bringing all of my Pii aboard the aircraft (probably connected to lapdocks), and since they provide TDRS-Internet-connected WiFi for the laptops the crew and researchers bring aboard, I hope to be able to provide access to the Pi community during mission flights. They left the original first-class seating aboard (now over 30 years old as the aircraft was mothballed by United in the early 1990s), so we get to ride in (ye olde) style during takeoff and landing. Pan Am's first class section was in the upper section behind the cockpit and business class was in the forward part of the lower deck, but United swapped them because the windows at the forward-most seats provide views looking directly ahead of the aircraft.

The entire coach section seating was replaced by the telescope, second pressure bulkhead, and consoles for telescope operators, astronomers, and mission specialists. Because the airliner emergency oxygen system was removed from the coach section during conversion, there are masks and hoses at the consoles, but we have to carry portable masks and tanks whenever we're out of our seats. We also have to go through special emergency procedure and evacuation egress training because of modifications to the aircraft.

Image

The program website is at: http://www.nasa.gov/mission_pages/SOFIA/index.html and the research site is at: http://www.sofia.usra.edu
The best things in life aren't things ... but, a Pi comes pretty darned close! :D
"Education is not the filling of a pail, but the lighting of a fire." -- W.B. Yeats
In theory, theory & practice are the same - in practice, they aren't!!!

Nige C
Posts: 46
Joined: Thu Jul 19, 2012 12:22 am
Location: Hadleigh, Suffolk

Re: Software Defined Radio

Thu Aug 15, 2013 1:16 am

Thanks for the info in your post above Jim, very interesting. I'm just an amateur player with my hobbies. I spent hours eyeballing meteorites the last few nights. The Perseid meteor shower is a good one to watch on a clear August night. My local council turns off all the street lights at midnight, to save money. I can see the Milky Way again, with the naked eye. Darker skies for all.

Have a safe flight Jim, I'm envious. What a fantastic event for all those taking part, and the Pi.
Retired power engineer with a lot of real life experience. Life is an adventure again :)

Gekko
Posts: 5
Joined: Wed Aug 21, 2013 1:11 pm

Re: Software Defined Radio

Wed Nov 06, 2013 2:24 pm

Hi N1njAgam3R,

I didn't implement the waterfall function but I have the frequency spectrum displayed along with various demodulations all running on the rPi just fine. Admittedly, there isn't much processing capacity remaining but if you reduced the update rate for the spectrum display, the waterfall would run fine Im sure.

Happy to share more details if interested

http://www.youtube.com/watch?v=l6OmfubTJ-o

http://www.youtube.com/watch?v=cJ2clOkILH8

Druid8172
Posts: 1
Joined: Mon Nov 11, 2013 1:01 pm

Re: Software Defined Radio

Mon Nov 11, 2013 1:09 pm

Gekko I am very interested in your set up please tell us more

User avatar
yv1hx
Posts: 372
Joined: Sat Jul 21, 2012 10:09 pm
Location: Zulia, Venezuela
Contact: Website

Re: Software Defined Radio

Thu Sep 08, 2016 5:30 am

Jim Manley wrote:
Nige C wrote:I follow a lot of the electromagnetic spectrum including light
Unless you're living on top of Mauna Kea where the only ground-based infrared telescope is located, you're missing one important part of the spectrum. I'm waiting to be scheduled for flights aboard the NASA and DLR (the German version of NASA) Stratospheric Observatory For Infrared Astronomy (SOFIA) highly-modified 747SP in 2014 for NASA's Airborne Astronomy Ambassador (AAA) program. The aircraft carries a 17-ton, (...snip...)
A CNN press note about SOFIA:
http://edition.cnn.com/2016/08/30/aviat ... asa-sofia/
Marco-Luis
Telecom Specialist (Now Available for Hire!)

http://www.meteoven.org
http://yv1hx.ddns.net
http://twitter.com/yv1hx

Return to “General discussion”