rtlsdr software defined radio

scratchpad by asbesto

Usare la chiavetta modificata

dEVICE Realtek rtl bla bla

device string: rtl=0,direct_samp=1

lbm lo deve essere a 0.00000 altrimenti va fuori frequenza!

Starting point

Compiling stuff is a pain in the ass.

Master references:


Do not use the dvb drivers on the CD or your OS. Those are for the dvb mode and not the debug mode that outputs raw samples. Linux 3.x kernel should check with "$ lsmod dvb_usb_rtl28xxu" and if found at least "$ sudo modprobe -r dvb_usb_rtl28xxu" to unload it. Be careful about gnuradio-3.7 installs that may leave behind problem files.

LNB_LO = 5.4 nel default.conf o nel setup, cosi' e' centrato in frequenza.

quindi per tuning di rai radio3, 98.7 bisogna settare

rtl_fm -f 98.7M -W -s 200000 -r 32000 - | aplay -r 32k -f S16_LE

The maximum range you can view on the waterfall is determined by the 
sample rate of the input device. If the input device is set to 200 
kHz, then the waterfall can show up to 200 kHz. 

Since you are using an RTL2832 dongle you can set the input sample 
rate up to about 2.4 MHz, which will give you a corresponding 
bandwidth on the waterfall. But to view the entier 20 MHz range from 
88 to 108 MHz you need to use a receiver that can sample with 20 MHz 
rate (+ a very fast computer). 



Maximum noise reduction

Stick wrapped in alu foil, foil touching the metal part of the USB plug, connected by an USB extension cable with the metal removed. Stick inside a metal enclosure, in the middle of 10m coax coil.

Result: no signal whatsoever, FM band is clear, waterfall is uniform blue.

Optional: ferrites if you have them.



Gnuradio is something different. ;)

RtlSdr (last edited 2019-03-14 22:25:40 by asbesto)