Posts by DB2OS

    Quote

    At least here in ON-country- there are in fact situation where encryption is not only allowed but even mandatory.

    1. - emergency communication carrying information about individuals.
    2. - to remotely control amateur-radio infrastructure,
    3. - to remotely control amateur-satellite radio infrastructure

    There is a general misunderstanding between 'security', 'safety', 'privacy' and 'authentication'


    In particular for Point 2. and Point 3. encryption is absolutely not required. On all P3-Satellites we never used encryption, but authentication.. There was no need to hide the commands, but indeed you wanted to make sure that only real command stations could execute commands. So instead of encryption, the protection was using a kind of trustable signature..


    73s Peter

    Hi Kristof,


    Quote

    If the message itself cannot be decoded -because it is encrypted emergency communication or some new experimental mode-, the listeners have no way to verify if that is indeed a message from that station.


    And this would be illegal anyway and I assume the user community will quickly start to find out what it is and start counter actions, as we have seen in the past.. quite successful actually.


    I assume that any proposal to experiment with new modes here on the transponder will follow the guidelines, international and local regulations, therefor it needs to be fully documented before any experimental transmissions takes place, to allow others to decode. Otherwise it would be treated as illegal..


    73s Peter

    Hi Kristoff,


    As far as I know, the proper standard "identification signal" given by ITU and local regulators for "experimental" modes is either speech or morse code for the callsign. It may also be possible to use other digital formats as long as they are well-known standards in amateur radio, easy to identify or decode. For example the "callsign" field in AX.25 Packet Radio became such a standard and Morse code identification was only required in the very early days.


    Indeed we are looking forward to see and learn more about your experiments than..


    73s Peter

    I opened my Opticum LTP-04H and it looks very different from the ones you have..

    Did you buy it recently??

    It's seems to be an very old one, obviously with DRO instead of XTAL and PLL..

    You can scrap it...


    Edit: Just noted.. on the sticker: yours is "blue" line, the correct one is "red" line.. so it's not the same..

    Version 3 February 2021 – The following updated DATV (DVB-S2) bandplan and guidelines are designed to enable the most efficient use of the QO-100 wideband transponder (WB) for all amateur radio satellite users. Please make sure that you understand the guidelines and follow them accordingly. The use of DVB-S2 as the most efficient transmission mode is advised.



    https://amsat-dl.org/en/p4-a-w…and-operating-guidelines/


    or for direct Download: QO-100 WB Transponder Bandplan V3

    this morning ISRO launched several satellites with frequencies in the amateur satellite spectrum, unfortunatly all of them seems to be without IARU coordination..

    • SDSAT 3 at 435.500 Mhz (uncoordinated)
    • GHRCESat at 437.500 Mhz (uncoordinated) and at 436.000 Mhz (uncoordinated)
    • JITSat 1 at 437.500 Mhz (uncoordinated) and at 436.000 Mhz (uncoordinated)
    • SSIETSat 1 at 437.500 Mhz (uncoordinated) and at 436.000 Mhz (uncoordinated)

    I've also got my BETA tester pre-order announcement by direct eMail :-)


    But here is something more interesting to learn about the antenna itself:


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    Enjoy, 73s Peter

    Hello,


    here is the link for tomorrow live stream of Mars2020 until cruise stage separation from Bochum


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    I will start the stream about 1h before cruise stage separation at 20:38 UTC, which is 10 minutes before EDL..


    73s Peter

    You are seeing a live spectrum view from Tianwen-1 telemetry transmitter received by the 20-Meter Antenna at the Bochum-Observatory in Germany. Tianwen-1 ("questions to heaven," or "questioning the heavens") is a Mars mission by China consisting of an orbiter and rover. It launched in July 2020 and enters Mars orbit on 10 February 2021 around 12:00 UTC. The rover will not land until May. Mission Lead: CNSA
    Follow us on Twitter: https://twitter.com/amsatdl
    For more details about our antenna: https://amsat-dl.org/en/20-meter-ante...


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    Tune in into our live stream and listen to the Emirates Mars Mission (EMM) Hope Probe when it arrives at Mars. We will track EMM with our 20-Meter Antenna at the Bochum Observatory about 2 hours before orbital insertion. Fingers crossed for HopeProbe!




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    Never say Never.. ;-)

    Good tracking programs are actually able to flip-over..

    Which means that with an 90° overhead pass you will have EL >90° ... <180° flip over...

    This is important with LEO satellites, in particular when you need to rotate AZ by 360° depending on where your Rotator Stop is (either Noth or Sourth)..

    If you have done the 180° calibration correctly, the 90° should be OK too.

    Again.. you have to mechanically bring it into 180° and make sure the antenna is horizontal aligned and only than you adjust the Potentiometer FULL SCALE ADJUSTMENT. And yes, the mechanical stop of the rotator is slightly more than 180°.. So you have to go in front of your house and check with your eyes if it's 180° or not :-)

    Most likely old Keplerian elements... calculated orbit and calculated doppler shift does not fit to the actual orbit. Please try updating the Keps and check if they have really updated..

    hello peter, meter functions properly and full scale adjusted - but the actual physical movement of the rotor arm is what I mentioned about going to 190 degrees or so. the picture i posted is about the antenna and not rotorator control box needle

    Yes, but how did you make the Full Scacle Adjustment than? I'm confused...


    You have to use the UP/DWN button carefully and turn your actual position of the rotor arm physically into exact 180 degrees... not as shown on the meter, physically!

    Then you adjust the potentiometer on the back side accordingly, so that the EL meter shows 180 degrees.


    From now on, whenever the meter shows 180° the rotator arm should be physically also 180°..


    If that's not the case, something is wrong.


    73 Peter

    0 is actual 0

    90 is close to 90

    180 degree is more like 190....

    It's called FULL SCALE ADJUSTMENT, please see Page 4 in the Manual, see the link from DM4IM.


    First do the ZERO adjustment of the meter with the screw below it (with power off), than bring your EL rotator *mechanically* into exact 180° position and use the Elevation Full Scale potentiometer on the backside to adjust the meter to show 180°. That's all... same procedure for AZ. This way you calibrate both meters on the Controller.




    73 Peter