i wonder if i am allowed to transmit such signals, maybe with some ham license? also, i read "exposes the RF link as just another Ethernet interface" a little wrong. its not like this will demodulate ethernet somehow but extracts frames from the transport stream using usual DVB mechanisms (i.e referencing the data stream in the PAT and similars) or am i wrong?
Those frequencies that I'm using (2305 and 3429 MHz) are in amateur radio allocations, so a license would be required (entry level Technician license will do). Because of that, you can't run any encrypted traffic over the link. So no https, ssh, etc. allowed.
With a license, you could transmit with up to 1500 watts (although it would not be easy). But you could easily run considerably more power than WiFi (like 10 to 20 watts).
Yes, I definitely simplified the explanation of the functionality of the driver. It's really a ULE (Unidirectional Lightweight Encapsulation) protocol driver. It processes Transport Stream packets received from the DVB-T2 receiver on a selected PID and forwards the data payload (IP packets) over the Linux Ethernet interface.
On the transmit side, I implemented the ULE protocol in GNU Radio (Github link in the diagram). To make the interface bidirectional, I capture transmit packets sent to the interface with libpcap as part of the encapsulation process.
I understand that the law requires you to broadcast unencrypted communications - but what happens if you don't and use it for long-distance SSH or something?
Who would respond? I'm genuinely curious - I recall a long time ago hearing a story about FCC vans with antennas driving around a neighbourhood trying to triangulate the signal and find the source but that was a much stronger "pirate" radio station.
Certainly not condoning it, but as long as you don't interfere with another user, you could get away with it.
For the frequencies I'm using, the 3.4 GHz band is very lightly used by hams, so that won't be a problem. Plus wide band OFDM signals just sound like noise in a narrow band receiver. There are government/military radars, but only in certain geographic areas.
2305 MHz is a little different. The 2305 to 2310 segment is shared with band 30 LTE. Band 30 is pretty lightly used by AT&T (the only licensee), but they do use it in some cities. The 2300 to 2305 segment is interesting. Amateur radio is secondary, but there is no primary user. My guess is that it's kept this way to provide a guard band to the deep space band at 2290 to 2300 MHz.
An alternative frequency would be 2395 MHz, but that's very close to the WiFi band. If you really want to be stealth, then 10 and 24 GHz would be ideal.
It depends where you are doing this? US? Australian outback? Developing country? The places you’d want to use it (outback) probably have low enforcement
