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One of my concerns with using an SDR is that the FCC basically requires DRM[1]:

> ...importers and marketers should ensure that [two-way radios] are properly certified and labeled as FCC-compliant and cannot be easily modified to operate outside its grant of certification.

So if you use an SDR for LoRa, you have to make it hard for users to modify the code to emit a different frequency.

[1]: https://docs.fcc.gov/public/attachments/DA-18-980A1.pdf




But this is a fully generic SDR. Can this even be certified as some consumer product?


I mean if you used an SDR in your consumer product. Let's say you make a dual purpose LoRa / WiFi radio to put in vehicles for a fleet management solution. If you use an SDR, you'd have to lock it down with DRM to prevent end users from repurposing it.


Using an SDR for this kind of product would be horribly cost and time inefficient. You would design it with off the shelf WLAN and LoRa ICs.

> If you use an SDR, you'd have to lock it down with DRM to prevent end users from repurposing it.

Not any more so than a product you designed that didn't use an SDR as its core.


Yes, but the same applies to your WiFi router even if it has hardware filters. Its simply a certification requirement.

That doesn't have anything to do with LimeSDR. This is already not a product that is certified for anything. It exists in a very gray zone where anyone using it for transmission is likely in violation of the law unless they obtained a development/testing license in the specific band they are using.


The easiest way to leave the gray zone would be to get a ham radio license. Although this might vary from country to country, generally you are allowed to use selfbuilt transmitters in specific frequency ranges, which also includes noncertified hardware.


I'm not too sure about that. Having a HAM radio license would allow you to transmit on bands licensed for HAM usage. A lot of the stuff that people want SDRs for (especially for transmitting) lies outside of those bands.


Or put the unit in a faraday cage to carry out testing. I believe a lot of people do this to allow them to play with transmission while not breaking any laws.


> likely in violation of the law...development/testing license

Or they just have a ham radio license


In a Faraday cage, no one can hear you transmit...


Well, it would also cost at least 10x what a dual purpose LoRA/WiFi radio would cost if it were built out of LoRa parts from Semtech and an ESP-32.


That document (DA 18-980) talks about "importing two-way VHF/UHF radios... used primarily for short-distance, two-way voice communications."

In other words: cheap walkie-talkies that don't comply with FCC regulations.

Such radios typically max out at 5w.

The LimeSDR claims 10dBm - which I believe means about 10milliwatts.

In other words, that FCC memo is concerned with radios being sold that are something like five hundred times as powerful as a LimeSDR. And therefore much more likely to interfere with other transmissions.


> That document (DA 18-980) talks about "importing two-way VHF/UHF radios... used primarily for short-distance, two-way voice communications."

I thought it was more along the lines of going after Baofengs, not CB radios, hence the calling out of VHF/UHF radios specifically.


This is probably true, meaning you can't really have a FCC certified tx-capable SDR. However in order to legally use the tx-capabilities of an SDR you probably have to be a ham anyway. And hams don't need their equipment to be FCC certified if I am not mistaken.


> However in order to legally use the tx-capabilities of an SDR you probably have to be a ham anyway.

You can transmit in the ISM bands without a license. There are still power restrictions which most SDRs won't exceed anyways.


Yes, a general user/consumer can transmit in the ISM band without a license, but they are still required to use intentional transmitters which have been certified by the FCC.


> but they are still required to use intentional transmitters which have been certified by the FCC.

For a hobbyist experimenting with an SDR, this wouldn't apply.




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