What to listen to over RTL-SDR?

[technix]

I have owned an RTL2832/RT820 RTL-SDR for a while already, but still haven’t got any idea what to listen besides local FM radio. Is there anything interesting in the airwaves?

I live in Shanghai, China. From the window of my room I have a clear line of sight to Shanghai Hongqiao International Airport (ZSSS/SHA) at a distance of about 5 kilometers. I have tried to tune into various published frequencies of the airport but I heard nothing.

Also, how do I build a frequency shifting adapter to bring local AM band into the range of this receiver? Will a fixed-shift fixed-band device work?

[hamster_nz]

It isn't listening, but a program called 'dump1090' will allow you to to track aircraft, and have some fun building and experimenting with antennas.

[technix]

It isn't listening, but a program called 'dump1090' will allow you to to track aircraft, and have some fun building and experimenting with antennas.

That would be interesting. If the antenna described in the README performed as well as the author claimed it would be a stress test for dump1090 and my CPU if I run it here, 5km from Shanghai Hongqiao and ~50km from Shanghai Pudong International Airport (ZSPD/PVG,) two of the busiest airports of the world well within its range.

[Halcyon]

Read about the POCSAG protocol. It's a pager protocol which is still in use today by many organisations including hospitals. It's super easy to decode messages (one can even do it with a traditional radio scanner and a sound card). Commercial paging systems are usually in the UHF range (~430-460 MHz range), but VHF systems also exist.

[HoracioDos]

Hi
As it was proposed before you can track planes. Easiest software to begin are piaware (flightaware), flightradar24 and plane finder. I have a raspberry pi running all at the same time but many can be compiled for pc. You can also try to listen trunk systems, sstv, aprs and many other things. I would recommend this book to start with.
The Hobbyist's Guide to the RTL-SDR
https://www.amazon.com/Hobbyists-Guide-RTL-SDR-Software-Defined-ebook/dp/B00KCDF1QI/ref=mt_kindle?_encoding=UTF8&me=

[Bicurico]

Of course you can listen to the pilots, too. They transmit in AM around 118-125MHz, usually.

Then there is:

Amateur radio: not that interesting anymore, IMHO.
PMR (446-448MHz): this is funny near or inside shopping malls, as you can listen to many communications of security staff and shop employees.
Taxi: at least here in Portugal, they use 170-180MHz

But that's about it, really.

Most communications are digital and with it comes encryption.

If you really want to dig deeper, learn how to use GNU Radio (works with RTL-SDR) and then you have a whole new world to discover, including digital communications.

Regards,
Vitor

[wkb]

Of course you can listen to the pilots, too. They transmit in AM around 118-125MHz, usually.

Then there is:

Amateur radio: not that interesting anymore, IMHO.
PMR (446-448MHz): this is funny near or inside shopping malls, as you can listen to many communications of security staff and shop employees.
Taxi: at least here in Portugal, they use 170-180MHz

But that's about it, really.

Most communications are digital and with it comes encryption.

Google for Telive, that software allows Tetra TMO digital.  The unencrypted networks only of course.  But there are quite a few unencrypted users out there, at least in the Netherlands.  Obviously you can forget Tetra users like police etc.

[sokoloff]

ISM band for reporting meters.
Other unlicensed bands (varies by part of world) for garage door openers, car keyfobs, etc.
LoRa transmissions.
Local police, fire, rescue radio (make sure this is legal, though honestly the chance of being caught is exceedingly low).
And, of course, DBS-TV signals, which is what most of the cheap dongles were originally designed to receive.

[Bicurico]

In Europe, you cannot receive Police, Fireman, etc. for a long time!

These services switched to TETRA, a digital network which uses encryption.

The only service you can receive i.e. in Portugal, apart from air traffic, is TAXI radio services. They still use analogue communications.

To be honest, not much is going on in the analogue radio world.

Even FM radio is being gradually replaced by DAB+: Norway already did it and most other countries seem to be heading 2020/2024 for the shutdown.

Regards,
Vitor

[technix]

In Europe, you cannot receive Police, Fireman, etc. for a long time!

These services switched to TETRA, a digital network which uses encryption.

The only service you can receive i.e. in Portugal, apart from air traffic, is TAXI radio services. They still use analogue communications.

To be honest, not much is going on in the analogue radio world.

Even FM radio is being gradually replaced by DAB+: Norway already did it and most other countries seem to be heading 2020/2024 for the shutdown.

Regards,
Vitor

Being a SDR, it doesn't really matter for what kind of modulation is being used, as long as there is no encryption, since all decoding can be handled by a GPU.

[RoGeorge]

Not exactly listening, but receiving images from weather satellites
https://www.rtl-sdr.com/rtl-sdr-tutorial-receiving-noaa-weather-satellite-images/

[james_s]

I listen to the police/fire/medic communications, aircraft communications, ADS-B transponders, and various 433MHz wireless devices on mine. I have no idea what sort of stuff is on the airwaves in China but anything aircraft related should be the same worldwide.