Posts by 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?

    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 ;)

    Mal ganz leise nachgefragt: gibt es neue Termine für UP Converter und LNB?


    Hallo Chris,


    hier mal eine ganz leise Antwort :)


    habe gerade erfahren, dass Ende dieser Woche, spätestens Anfang nächster Woche die Baugruppen und LNB's in Bochum ankommen sollen. Ende nächster Woche sollte es dann losgehen können und das lange Warten hat sich hoffentlich gelohnt..


    Am Wochenende haben wir dann auch die Preise kalkuliert und müssen noch die Seiten im Shop einrichten...


    73s Peter

    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

    The "reference" is always the lower CW beacon, as the upper (experimental) beacon might use different modulation in future.

    As said before, leveling is not yet finished.. we are happy the new (PLUTO based) hardware is running fine..

    I assume the upper beacon level will be adjusted soon...

    73s Peter

    Ah - So you mean this beacon is from AMSAT, not an allocation to put beacons in. I miss-understood. Lets hope it is something more interesting that 400 baud BPSK.

    Yes, as mentioned in the article New QO-100 band plan there are plans to have some sophisticated modulation and coding on it, to allow extreme weak signal reception. For example just with a handheld LNB.. maybe DXCluster information, kind of SMS service, etc..

    Mario DL5MLO is working on this stuff...

    more Q&A:

    Are there any restrictions on the experimental section? E.g. bandwidth, signal level, length of transmission? I realise it is only 5kHz wide but we can't all use all of it all of the time - or maybe we can with some modes.


    There seems to be a misunderstanding:

    The "EXP Beacon" is now introduced as the former "Upper Beacon", as the old PSK-Beacon is now the Middle Beacon ;)

    This section has to be cleared from any use or interference: including Guard bands like the other beacons.

    Mixed Modes (10.489,850 to 10.489,995 MHz)

    The mixed mode section moved completely to the new area at the upper end of the transponder, just above the SSB-Only section.

    Indeed the Mixed-Mode is fully available to all users, including SSB :)

    The additional term "special purpose" means, that some frequency might be reserved for other purposes later. Those will also be marked in the bandplan.. As of today (Feb. 15th) there are now restrictions other than the maximum 2.7kHz BW.


    Do I interprete it right, that in the mixed mode segment 2700Hz BW limitation is suggested for "normal mixed modes", but that this does not apply for the "special purpose" use, as nothing is mentioned ?


    There is no change on the maximum allowed bandwidth of 2.7 kHz modulation. This limitation is still valid for the whole NB transponder without any exception, including special purposes (see also on our webpage as mentioned above).


    "Special purposed" is meant for disaster communication and other activities we are reviewing at the moment, including call-in channels etc.. nothing specific defined yet ;)

    We were planning to have the FUNcube telemetry 1K2 PSK beacon from Antarctica (DP0GVN) there, but this project has to be delayed until next year.


    The only remaining question would be, what qualifies for "special purpose"....? And should this be done in agreement with AMSAT?

    As usual, any automatic or unattended operation requires a special license from the local licensing authorities and must be coordinated with the operator beforehand. This task is performed by AMSAT-DL on behalf of QARS and Es'hailSat.

    Some Q&A:


    • which one of the CW tones is the actual nominal beacon frequency? Is it the lower tone on 10.489.500 MHz and the upper one on the 10.490.000 MHz?
    • how accurate are these frequencies from Bochum? Can they actually be used for calibration?

    All Beacons, LEILA and Up-/Down-Converters are stabilized by an high precision GPS locked Rubidium 10 MHz reference oscillator:

    • 10 MHz Rb-Normal, HP Z3801 (GPS-locked)
    • Allan-Deviation ca. 1E-11 (tau=100 sec)
    • complete RX & TX chain phase locked


    Lower Beacon (CW) is on 10.489.500 MHz, Middle Beacon (PSK) on 10.489.750 MHz, Upper Beacon (CW&Experimental) on 10.490.000 MHz


    Some small offsets might be possible, and also due the Transponder itself.


    The new Beacon/LEILA hardware in Bochum is now based on ADALM-PLUTO.

    Thanks Alex for your proposal and open discussion, which is very important to me.

    There are still a lot of "white spots" on the footprint of QO-100 and I hope there will be more activity in the future..

    On the other hand, I think we should not create traffic only to generate traffic with no real benefit..

    I did read somewhere that much more than 1000 POTY feeds alone have been sold and a lot of other solutions like Bamatech feeds too... But where are all those people ?(

    Are they scared, too shy? Did they give up somewhere?

    What can we do to help them?


    73s Peter

    The transponder bandplan and guidelines already clearly say: Remote operation over Internet (Gateway traffic) is undesirable and only permitted during disaster communication.


    Personally I don't see any benefit from such a gateway no matter if it's internet or shortwave.


    We should encourage people to receive by themselves instead of using WebSDR..


    We need to more encourage and support those amateurs in remote or underdeveloped countries to get active via QO-100.