LEILA-2 operation

  • I remember having read somewhere that LEILA-2 monitors 'channels' of 2500 Hz BW and have some questions concerning the proposed/designed operation of the jammer (not primarily related to 'channels', but in general).

    Imagine the following:

    1. I generate a single tone/carrier just below the LEILA-2 threshold (so LEILA-2 will not jam) with 'xW RF'.

    2. Next, I generate two tones 1234 Hz apart with equal amplitudes with the same 'xW RF' in such a manner that each tone/carrier is -3 dB cf to 1.

    3. Then I Increase the RF output with +3dB (so each tone/carrier is of equal strength cf to one carrier in 1).

    What will LEILA-2 do and/or is intended/designed to do?

    Situation 1. (Hopefully nothing ; -)

    Situation 2. ?

    Situation 3. ?

    Edit: DB2OS Accidentally posted this in the 'Hardware' thread but maybe it should be in the 'bandplan and operating guidelines'? If so, can I move the thread myself or are you willing to?

  • If on your SSB "channel" is LEILA-2 alarms and you are absolutely sure that your TX power is OK, or there is indication that other party use too much power, send him/her QRP.

    It is interesting what will happen on FT8 "channel". Maybe next WSJT-X versin will have following automatic feature: When you see your call and QRP your software automatically decrease volume by 3dB. It is like this:
    1. somebody send: "CA1LL QRP"
    2. WSJT-X, who have CA1LL, automatically decrease audio out volume by 3 dB.

    But there is possibility to to hijack and remotely make somebody "silent".

    P4A will be really interesting new experience.

  • No, that won't work, because the station that triggers LEILA won't even hear the LEILA. And afaik this LEILA system used on Eshail'2 is passive! That means that users *must* listen to their own downlink - running simplex would be outrageous ;-)

    Yes that is the issue. Some users decide not to abide by the regulations or recommendations, even when it comes down to something simple like "use your callsign as a username on the forum". Let alone to "only use fullduplex capable equipment on the satellite".

    What can we expect when it is recommended to them to use less power? They could just choose to "agree to disagree" and continue.

    However, we can assume that it will not be as bad as on the local 2m or 70cm repeater, because there at least is some effort to make to be on the satellite, not just "order a Baofeng at Aliexpress".

    Still, to remain ontopic, we have to be careful because we do not yet know the performance of the transponder when in full normal use, but the first tests indicate that we do not need to worry about "being able to receive it even with some de-sensing". If anything, the users of those huge dishes should worry about intermod in their frontend :-)

  • Another idea for monitoring: BATC will provide webSDR, so you can always monitor downlink from webSDR.

    I'm afraid people who now worry about the roundtrip delay ( = no experience on Phase3 satellites) will not want to listen to a WebSDR which has even more delay.

    However, it could be considered to make LEILA behave so that when a station repeatedly triggers the LEILA and does not appear to reduce power, the siren tone also continues for some time after the transmission has ended, so at least they are warned when they switch to receive.

  • No, that won't work, because the station that triggers LEILA won't even hear the LEILA. And afaik this LEILA system used on Eshail'2 is passive! That means that users *must* listen to their own downlink - running simplex would be outrageous ;-)

    OK, verstanden.

    This answers also the question of simplex or fullduplex. Ergo: ALLWAYS FULLDUPLEX!

    73 Thomas

  • 'Split operation is not desired on the satellite' <--- ???

    Says who.... and why not 'desired'? It can't be enforced.

    It seems to me like the 240 kHz (- two beacons) is already over regulated before the transponders are on ...

    Let me give my 2 cts: "Speaking Russian is mandatory" ; -)

  • How are DXpeditions going to work via the satellite? Split operation is not desired on the satellite. Is there a plan for this case?

    Due to the fullduplex nature of satellite operation the calling stations can judge by themselves if they are being heard or if another station is stronger so they can stop calling for now. So at least part of the reason for operating split is not valid on satellite.

  • DL9DAC : That's exactly the reason why I started this thread with the LEILA-2 questions. Later DB2OS added some posts concerning 'operations' to this thread

    so that the initial incentive seems under illuminated.

    I don't think the pile-ups itself are an issue, but the way LEILA-2 deals with them.

    So, will LEILA-2 do only a 'peak' analysis (inside a 'channel') or will it take the integral of all signals (inside a 'channel') ?

  • I am asking because stations calling the the dx station will most likely not be listening on their split tx frequency while calling and therefore not hear the LEILA warnings.

    ... the good thing with QO-100 is: a rare dx station will create a pile-up at first, but if you are a little bit patient and give it a few days, the dx station will call you in the end. The amount of stations accessing the satellite (currently) simply is too low to create an hour-lasting pile-up.

    Best 73

    Holger 'Geri', DK8KW