Tag: software defined radio

Posted on

maxradio updates

Upgrade to Mac OS Max version.

Windows, runtime, standalone, and documentation upgrades still in progress…

changes

This is an interim update to add new drivers.

  • driver for rtl-sdr
  • minor bug fixes

download

https://github.com/tkzic/maxradio

instructions

  • Connect a radio
  • Open maxsdr7a.maxpat 

note: 1/23/2015 – the repository was really messed up – missing externals, etc., have reloaded. The local source is now at tkzic/maxradio

Posted on

ep-4yy13 DSP – week 13

“I think its just the biggest conceptual art project uninentional or otherwise that anyone ever made. it puts Christo and those other guys to shame. Its planetary”

Roman Mars “Episode 97 – Numbers Stations” from 99% Invisible

Radio

  • Measuring the invisible
  • What is the difference between sound waves and radio waves?
  • What is an antenna?
  • Wave propagation is frequency dependent
  • Sunspots and magnetic fields http://spaceweather.com
  • Extreme frequencies, negative frequencies?

examples

Internet radio streams and recordings

Frequencies and modes
  • Macbook trackpad: Noise 5 mHz. (try holding radio near screen too)
  • Macbook AC adapter: Noise 600-1400 kHz. (~1000)
  • AC adapters, LED’s, Utility poles: 3.2 Khz
  • Arduino transmitter: AM 1330 kHz.
  • Laser light at 650nM
  • Wireless micorophone (Orange-brown): Wide FM 614.150 MHz. (R band)
  • Cordless phone: Narrow FM 926 mHz.
  • Cell phone: Digitally encrypted trunking FM 836 mHz.
  • Wifi: Digitally encoded PCM 2.4 gHz.
  • FM broadcast band: Wide FM 89.7 mHz (Raspberry Pi example 98.1 Mhz)
  • TV audio 600 mhz/660 mhz FMW
  • The sun http://www.ips.gov.au/Solar/3/4

Topics not covered

(due to snow and stuff)

Visualization

 

  • d3
  • processing
  • jitter
  • hardware control

Statistics

Miscellaneous

Assignment

Please send me a copies of your earlier compositions. Have a prototype ready to demonstrate or talk about for the next class.

 

Posted on

rtlsdr, Pd, linux

notes

Today was able to get the rtlsdr~ object running in Pd on Ubuntu 14.04 on a Macbook pro.

Audio quality seems rough. The only driver I could get to work was Alsa at 44.1KHz – may be able to get help with this from Pd community.

Ended up using 64bit libraries for librtlsdr and libusb-1.0 . In fact, needed to using the shared (.so) libraries, not the static ones (.a) due to a weird linker error. Its possible that it happened due to mixing shared and static and I might try again using both static for these 2 libs.

See notes from previous post about issues with USB capture, and non-root user in Linux – there are 2 flags on the cmake for rtlsdr that might help resolve both of these, but I wasn’t having any luck and needed to use the method described in previous post.

The source code for linux version is in the /usr/lib/pd-extended/extra/rtlsdr~ folder – and the test pd file is in ~/pd/rtlSDR-block.pd, along with some abstractions.

There is also a makefile to build a local version of rtl_fm (rtl_fm3.c) in ~/rtl-sdr-new/rtl-sdr/rtl-fm3/

This makefile mixes the static and shared libs with no problem… hmm…?

next

Need to package this stuff up and send it to pdsdr github with source for Max/Pd on mac and Pd on linux. + instructions… etc.,

Would like to try running on r-pi – but will need to adapt the test patch to receive Osc messages because there is no gui on r-pi

Also I am some skeptical about running at low sample rates for audio – we’ll see…

another note

Just thinking, that even if I am not able to run rtlsdr~ on r-pi that we could adapt rtl_fm so it receives control input from Pd using Osc and work that way…