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Comment by Eehoj2zaiph | Hacker News Reader

Broadcast meaning unidirectional, with support multiple receivers, and no association or acknowledgements required.

Correct me if I'm wrong, but I don't believe there is a "broadcast mode" for wifi.

So I'm asking if there is some SDR software/hardware combo that works well for this purpose, or if re-purposing wifi is the best option.

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UDP requires some physical layer, which 802.11 provides. There are others, but in any case, you can't just "broadcast UDP" over the radio by itself.

Yes, of course. Any suggestions on SDR-based hardware/software options?

We broadcast UDP over various satellite transponders. We have also done this over terrestrial links. We've done UDP file broadcasting over DVB-S/DVB-T/LoRa/FSK/etc with forward error correction in the client/receiver. Feel free to contact me. Email in my profile.

That was the question, how to implement those layers. Why complain about terminology, what does it contribute? Can you recommend specifics?

The question was too underspecified to give a good answer. It's the equivalent to asking "can I send data over the internet"? The answer to the question as-asked is "yes", but the details will be substantially different depending on what you're actually trying to do.

The question was precisely much more specific than "data over internet".

They indicated that they had UDP packets, which is the specification of the application layer, it means that they have an application that already works with UDP and they just want to send them over the radio, bypassing WiFi protocols/cards etc, from an SDR to an SDR directly. It means that whatever solution is, if it can work with UDP, if the underlying layer translates data into UDP, it will work with their application. That's a very precise specification.

> from an SDR to an SDR directly

That wasn't actually stated. Maybe OP has a bunch of laptops with WiFi cards and no access point and wants to broadcast data to them with the laptops listening in monitor mode. Or maybe OP has a bunch of laptops connected to an access point and wants to broadcast to them using IP multicast. Or maybe OP really does have a bunch of software-defined radios and wants to directly encode UDP packets into IQ samples. Don't you think those would be three very different solutions?

You definitely can broadcast packets via wifi. I mean, that's essentially what you're doing when talking to an AP. All the other wifi antennas/chips in the area can see the data you're sending. You'd have to do some hacking on the receive side to get the data out, but that should be pretty straightforward.

To receive, just set your interface to monitor mode, set the right channel, dump and filter. tcpdump works fine, though you probably want to read and process the data with a custom application.

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