SDR Quest: Looking for Software Defined Radios for FreeBSD

Pulling a stunt like that will likely result in getting arrested pretty much anywhere in the world. That said, it's quite frightening how atrocious the security of those systems is.
 
SirDice said:
Used mine to pick up ADS-B (aircraft transponders) from aircraft flying overhead.
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That is a great usecase. ADS-B . We have alot of little birds around here that are not on flight trackers.

So can you multi-task your SDR? Showing streaming NOAA maps and scanning the sky for birdies?
 
Phishfry said:
So can you multi-task your SDR?
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Don't think that's possible with a single device. Although it could constantly switch frequencies, you're probably going to end up with gaps in the received NOAA picture. It can't listen on two (or more) different frequencies simultaneously. Maybe a more expensive SDR could (multiple receivers, each tuned to a different frequency).
 
I noticed in my reading that GNU-Radio can take multiple inputs.
That makes sense as even though you have a "universal radio" a task suited antennas would be best.

RTL-SDR Tutorial: Cheap ADS-B Aircraft RADAR

The RTL-SDR can be used as a super cheap real time air radar. Modern planes use something called an ADS-B (Automatic Dependent Surveillance-Broadcast) Mode-S transponder, which periodically broadcasts location and altitude information to air traffic controllers. The RTL-SDR can be used to listen...
www.rtl-sdr.com

What about "Point to Point" connections. I see the term 'modem' used for SDR radios.
Can I use a pair of SDR devices that can do TX/RX to transfer files between them? xmodem possible? PPP?
How do you connect two SDR base stations without the internet?
 
SirDice said:
Don't think that's possible with a single device. Although it could constantly switch frequencies, you're probably going to end up with gaps in the received NOAA picture. It can't listen on two (or more) different frequencies simultaneously. Maybe a more expensive SDR could (multiple receivers, each tuned to a different frequency).
Click to expand...
This is correct. The bandwidth of a regular dongle is 2.4 Mhz, so you can capture only a narrow band. The websdr station I linked previously is unique in that it captures a huge range, but at a cost of using a custom FPGA to be able to handle the DSP.
Phishfry said:
I noticed in my reading that GNU-Radio can take multiple inputs.
That makes sense as even though you have a "universal radio", task suited antennas would be best.

RTL-SDR Tutorial: Cheap ADS-B Aircraft RADAR

The RTL-SDR can be used as a super cheap real time air radar. Modern planes use something called an ADS-B (Automatic Dependent Surveillance-Broadcast) Mode-S transponder, which periodically broadcasts location and altitude information to air traffic controllers. The RTL-SDR can be used to listen...
www.rtl-sdr.com

I guess sky facing antennas for both these tasks. Satellites and Birds.
Will I become a target for these little birds for scanning them?

What about "Point to Point" connections. I see the term 'modem' used for SDR radios.
Can I use a pair of SDR devices that can do TX/RX transfer files between them? xmodem possible? PPP?
How do you connect two SDR base stations without the internet?
Click to expand...
Most SDR dongles are RX only.

What you seem to be describing is LORA (433 Mhz or 915 Mhz). The most popular options are meshtastic, meshcore or reticular. They typically run on a dedicated ESP32 board, and it's line of site only (meaning you need to physically see the antenna you want to communicate with).

Some devices allow TX, but even the HackRF one one support RX or TX at a time, not both. For a good TX SDR, you're talking thousands, and realistically you need a license for anything more than 2W, and that's for commercial hardware. Non-commercial equipment requires a license even below that (because custom equipment might generate unexpected interference a non-qualified individual might not realize).

Not all dongles are created equal. For example, I have a USB-to-LoRa stick from Waveshare, but it's completely useless since it uses a custom protocol and doesn't support LoRaWAN. If you're doing LoRa, you want LoRaWAN capable dongles.
 
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