Obtain software that will enable you to listen to a wide range of frequencies – Police/Fire/EMT, Airports, CB, Ham bands, even the fast-food drive through; and there are many frequencies coming in from space – a good antenna is crucial.
This page is frequently updated.
Easy intro to radio astronomy: start with SDR.
First, I am a General class amateur radio operator (HAM). This experience has given me valuable experience on getting a start in radio astronomy. As part of my radio hobby, I like to download and decode NOAA weather satellite images: these satellites are quite old (only 3 are operational now) and they still use the older VHF signal – easily accessible to HAM’s and amateur decoding software.
I use Software Defined Radio (SDR) from SDR# – https://www.rtl-sdr.com/
It is good to have a preamp, as most signals will be very weak. I use a P136VDG from AR2: http://www.advancedreceiver.com/
Antenna: the RTL-SDR dongle can be ordered with the simple antenna shown. I use this when I am scanning local radio channels; but when I am scanning satellites and signals coming in from the Cosmos, I use either my discone or “eggbeater” antennas: Discone – https://www.dxengineering.com/parts/cma-ds-150s Eggbeater – https://www.dxengineering.com/parts/msq-eb144rk2m
For the weather satellites, I use the eggbeater up on my roof. For higher frequencies in the Gb range, use the discone.
Putting it all together
Aaron D. Parks shows you how to put it all together using SDR#:
Radio-Jupiter Pro 3: http://www.radiosky.com/rjpro3ishere.html
Itty-Bitty Radio Telescope: http://www.aoc.nrao.edu/epo/teachers/ittybitty/procedure.html
RTL-SDR dongles: https://www.rtl-sdr.com/buy-rtl-sdr-dvb-t-dongles/