LoRa via QO-100

1st Official Post
    • Official Post

    Congratulations to OE3DMB for the first successful LoRa-Transmission via QO-100.


    see this article: https://aprs.at/index.php/2020…a-aprs-via-qo-100-oe3dmb/


    Unfortunately we also have some conflicting interests here.


    The LoRa transmission on the NB was with 125 kHz wide bandwidth, which exceeds the maximum bandwidth of 2.7 kHz by a factor of 50 !! Some kind of early notification and coordination should have been a good idea.

    In fact we have noticed the (weak) noise band on the transponder at some stage...

    On the good side, the author already relativized his experiments in a final statement, which I feel is important too.


    But there is a another critical issue:


    The LoRa physical layer protocol is proprietary; therefore, there is no freely available official documentation and you are depending on the LoRa-chips (or licensed) from Semtech.

    Per sé that means we are not allowed to officially use LoRa on amateur radio frequencies.

    I understand there is some usage already, but I guess it's operated under general ISM regulation, as it uses or share the same frequencies with ours... A kind of grey zone...


    I was already thinking about using LoRa for another (yet undisclosed) AMSAT satellite project discussion in 2018, but already had some ideas in mind because some variants of LoRA chips support 800-900 MHz and could be directly connected to the LNB for receiving. For transmitting the new AMSAT-DL UpCon6W would also fit perfectly..

    If we would uplink LoRa from Bochum, it would be possible to receive data packets just with an LNB without any dish!


    We could discuss more of those ideas here, but the above "legal" topic is currently more important and we need to this solve first...


    So if someone is having any background about the "proprietary" part of LoRa and how to legally deal with it inside of our amateur radio and amateur radio over satellite service, I would be grateful..


    73s Peter

    About the proprietary nature on the amateur bands, this conversation's been had a lot over the years about various other popular proprietary modes or codecs and I don't see any restrictions that prevent the use of licensed chips/code. This might vary country to country?


    Use of reverse engineered things on the other hand, yes there are obvious legal issues here but outside of the scope of our radio license.


    I'd say either stick to something that uses the official licensed technology or code and take advantage of the cheap chips, or come up with something (better?) that does not. I'm not sure a hybrid approach would be workable for anything officially sanctioned.


    I did run some brief LoRa tests on the wide band transponder last year using the official chip in to a transverter and an SDR + GNU Radio for the decodes. I didn't progress this beyond receiving my sent messages or the next step using an proper chip to decode as other than for curiosity I didn't see any purpose to using LoRa here.


    I've found https://github.com/rpp0/gr-lora to work better in practice than the one linked which I struggled with.


    I contacted one of the chip suppliers in the past as noted they had a 14x MHz option printed on the board for testing in our 146MHz wideband frequency allocation here but they had not actually made any. They suggested a large order would enable their production or alternatively for test purposes just use the existing 433 one where they should work for test purposes but with bad performance. Never got around to testing if what they said was correct but it might mean the 869MHz ones may work to a limited extent a good bit off frequency.


    Happy to run any tests if anyone wishes to.

    • Official Post

    Actually what is LoRa's proprietary is the modulation: Chirp Spread Spectrum (CSS)


    There is no encryption, if you buy the chip you buy the proprietary modulation and pay for the license...

    But isn't this still somehow a kind of encryption or obfuscation?


    What happens if I create a proprietary modulation on our next satellite and only when you buy the modem chip from AMSAT you can access it? Sounds like a business model ;)

    Quote

    What happens if I create a proprietary modulation on our next satellite and only when you buy the modem chip from AMSAT you can access it? Sounds like a business model ;)

    That sounds like what is being proposed for Phase-4B by the Open Research Institute in the US. It's truly scary that this sort of thinking is seeping into our bands.

    I have some slides from their talk at Hamcation. The transport layer is DVB-S2 but being used for data/voice rather than video. It includes access control and other non ham friendly technologies, not to mention the large amount of technology needing to be flown on a satellite in a radiation unfriendly environment.


    It is probably tied in with it being for use by FEMA also, in which case I don't think it deserves to be called phase-4B or be within our bands. That's my opinion anyway.


    They also did a presentation on QO-100 before phase-4B which mis-characterised our beautiful satellite in many ways, although that was through ignorance I think.

    Hi Peter,



    Thank you for the congrats. Please let me take the opportunity to give my congratulations back to you for bringing a great bird into the sky and supporting the ham radio community with perfect service!



    As this forum is mainly in English I’ve translated my documentation about the LoRa APRS experiment via QO-100 into English language and would like to provide it here, so that everyone in this forum can read my text: https://www.dropbox.com/s/84zl…Ra_Documentation.pdf?dl=0



    I know of course that 125 kHz Bandwidth is far outside the specification of transmissions for the NB transponder. When I began with the experiment and repeatedly at certain improvement stages, I checked the downlink at my own station and also via the BATC web-sdr and didn’t see any noise in the waterfall, nor did I experience any disturbance receiving an SSB signal. So, I assumed that I didn’t cause any disturbance with my experiment from a user perspective. In other way I would have stopped my experiment. But I agree, you as service provider must have much more detailed insight into various transponder stages and surely you may have found my LoRa Signal.



    I don’t think that there is a problem using LoRa in the amateur radio service, at least in Austria. I know that there are certain differences between German and Austrian amateur radio regulations. For example in Austria FM repeaters need to shut down the TX not later than 10 seconds after the last voice transmission, while in Germany repeaters are often active for a minute or more. So maybe there is a restriction on using LoRa in Germany, but I don’t think there is one in Austria. We had some problems using D-Star back in 2007, when it came to Europe. The Austrian ‘Amateurfunkverordnung’ https://www.ris.bka.gv.at/Gelt…n&Gesetzesnummer=10012930 (unfortunately only in German) was then restricting transmissions to certain emission classes and W7D, which is D-Star, was not included in the list of allowed emissions. Therefore the law was changed in 2008 and now §7 allows ‘ALL technically possible transmissions’ for radio amateurs in Austria.



    I really don’t think that a new modulation technique is a kind of encryption, which wouldn’t be allowed in Austria as well. If you don’t have a packet radio modem or a sound card with the needed software package or some other means to decode you would not be able to receive and display packet radio signals. If you don’t have a LoRa chip, you are not able to receive LoRa transmissions. I don’t see a big difference here …



    Anyway, I hope that there will be a clarification on the use of LoRa in amateur radio soon. As we are now in contact, I hope we will keep in touch, so that I can inform you if I have new ideas for not-bandplan conforming Experiments before going on air. ;)



    73s de Andreas, oe3dmb

    Dear Peter,

    dear all,

    certainly LORA is fully legal to use in Amateur Radio in most countries. It is not encrypted. It might be proprietary, but C4FM, DStar, DMR P25 is the same in many aspects and still widely used in Amateur Radio Service. Lora-APRS is fully compliant with the APRS standard from Bob Bruninga, WB4APR. So in terms of "experimental" we should welcome these experiments. Ofcourse it is true that the bandwith will only fit the QO-100 wide band transponder. But I understand, that the wide band transponder is intended not exclusevely for DATV, but also for such data transmission experiments and services. Lora is a good example that not only very narrow banded modulation techniques (FT8, WSPR) can give excellent results with very low power but also "spread spectrum" type (see GPS).

    Currently LORA-APRS is spreading accross Europe on 433.775 on 70cm band (https://www.lora-aprs.at/) . WIth just 50mW you can make position data transmission over 100km from your car or backpack. So to have a Region1 APRS channel for Lora-APRS on QO-100 could be a super service also when travelling very remote areas in Africa or elsewhere...

    So lets welcome innovation in Amateur Radio!


    73 de Mike, OE3MZC

    I must take issue with that. All of the digital voice modes are fully documented, as they have to be so they don't appear as "codes or ciphers" to quote the UK licence. I wouldn't have been able to create the MMDVM otherwise.

    Jonathan,

    I appreciate ur work on MMDVM, but I am not sure abt ur statement:

    For example, DMR is originally not open and fully documented. Some things have been reverse engeneered. We all mostly use MotoTrbo Tier2, which is fully proprietary of Motorola (even with Hytera radios) and also your MMDVM is using a VOCODER-chip (AMBE), that you need to buy and use in hardware in order to have a license for it. So I cannot see any difference to Lora at all. So also Lora is fully documented and you can buy chipset for 433MHz very very cheap! So why not using it?

    73 de Mike

    I don't want to start a flame war, but you are incorrect on many counts. Tier 2 is used by everyone, I think you mean tier 3.


    The MMDVM does not include a vocoder chip and uses no proprietary technology. It is all open source of course. All of the protocols used are fully documented and can be found on the Internet, although P25 takes some finding.

    • Official Post

    Hello Mike OE3DMB and Andreas OE3MZC,


    Many thanks for your positive feedback. These kind of open and hassle-free discussions are very welcome,


    After some internal and external discussions, I'm not really thinking that LoRa is fully legal, but probably more in a “tolerated grey zone”:


    ITU-RR and so the local authorities clearly demand “open language” in the amateur-radio and amateur-satellite service, which is to be translated as “open modulation and open protocols” in modern digital modes by means of publicly available documents and descriptions. Furthermore, “encoding” (not to talk about encryption) as a sort of obfuscation is not allowed in our amateur radio services.


    When AMSAT first introduced the 400 Bit/s BPSK telemetry on the P3-satellites, it was required to publish all details (modulation, protocols, etc.) beforehand in public, for example widely available amateur radio magazines. Otherwise I would probably never became interested in amateur radio satellites and AMSAT, when my brother and myself build our own hardware and software to decode the telemetry from OSCAR-10.


    OK, we can buy the LoRa chip...


    LoRa is using proprietary encoding in the physical layer. Would LoRa be “patented” it would be openly documented, but they would disclose their intellectual property than. Only protected by patents, others could copy or modify it. Expensive and lengthy patent lawsuits would be the result. Sometimes it is easier and cheaper to keep these details secret instead, as with LoRa. So they indeed use some kind of "obfuscation" directly in the physical layer (modulation) to deal with this business model.


    I think it’s not even good to argue with D-STAR and the questionable AMBE Vocoder. When I was looking for more information, for example on Wikipedia, there is a lot of criticism and commercial fighting involved. AMBE is obviously patented and everyone who wanted to use it had to pay a high license fee for it, as part of the silicone price. In 2017 the patents have expired, obviously opening the doors for free open source software solutions probably ending these endless discussions…


    Maybe a good compromise is to argue that the LoRa-Chips are widely available at reasonable price and not limited to closed user groups.


    Anyhow, I'm not against LoRa.. the opposite is true.. But before using it, I wanted to to better understand the legality of it..

    But I have to confess, there is no black or white.. it's in the grey ;)


    On the other hand, it's an very interesting technology to play with and evaluate.. and that's also the purpose of our hobby...


    73s Peter

    Quote from DB2OS

    Well, I'm not promoting this proprietary stuff in any way...

    I'm really curious about how to deal with it.

    Also how some people can claim it's legal in their country? Anything official or written available?

    I was giving a talk recently on the use of 2.4Ghz LoRa and ranging, this issue came up.


    Its perhaps interesting to read what the UK regulations say about the use of encryption;


    11(2)(b) of the UK Amateur license Terms, conditions and limitations says;

    “Messages sent from the station shall not be encrypted for the purposes of rendering the Message unintelligible to other radio spectrum users”


    Which seems clear, you can use encryption as long as the 'purpose' is not to make the message unintelligible to other radio spectrum users. If encrption were not to be permitted at all it would be easy for the regulations to say so.


    Most amateurs would use LoRa for the 'purposes' of long distance low power communications, not to prevent outhers reading the messages.


    The UK regulations also quote in several places where you must not use encryption, such as some circumstances when sending messages to other countries. If there are times when you must not use encryption, it must otherwise be permitted.


    So even if you take a somewhat perverse view that the LoRa encoding which can be read using open source equipment, is still encrypted, then at least in the UK its use is permitted anyway.

    I believe the US licence states that encryption is not allowed, except by ground stations controlling amateur satellites. I would guess that our licence is rather lenient compared with others. Can you imagine any other licence using the phrase "from time to time" for the time interval for testing the stations transmitters?

    • Official Post
    Quote from GW7HPW

    11(2)(b) of the UK Amateur license Terms, conditions and limitations says;

    “Messages sent from the station shall not be encrypted for the purposes of rendering the Message unintelligible to other radio spectrum users”


    Which seems clear, you can use encryption as long as the 'purpose' is not to make the message unintelligible to other radio spectrum users. If encrption were not to be permitted at all it would be easy for the regulations to say so.

    That is indeed a very interesting interpretation ;)


    Honestly, it does somehow not make sense to me...

    The only reason why someone would "encrypt" something is for hiding and obfuscation or what would be the purpose otherwise?

    Encoding is a completely different thing, which is often confused with encryption, although the effect might be the same..


    As I wrote earlier in this thread, german administration is following the ITU-RR rule of "open language" and "Encryption" is only allowed for satellite control..


    But that does not make sense either because people don't understand that you can make a secure connection even without encryption..


    On a satellite command link, you want authentication to avoid someone is "hijacking" the satellite.. but that does not mean you have to encrypt.. You just create a "signed" envelope.. Something like a CRC across the content or a "signature" like in PgP with the key only known by the sender and receiver.. Thus you have a secure command link, but the contents of the messages are still readable. The AMSAT P3 satellites already implemented this technique 40 years ago !!


    From my point of view, Lora is not encrypting !!


    It is just using coding in the physical layer (modulation) . Indeed it is undisclosed, but legally a different matter...


    My last non-informal information of the BNetzA is (via DARC): "As long as you can buy a freely available device to listen to the communication, everything is OK... "


    To me this would make sense...


    73s Peter

    Quote from DB2OS

    Honestly, it does somehow not make sense to me...

    The only reason why someone would "encrypt" something is for hiding and obfuscation or what would be the purpose otherwise?

    I dont think I am just interpretating it in a way that is helpful to Amateurs, its clear (from the regulation) that the often repeated myth that Amateurs cannot use encryption (in the UK) is not true ....................................