Posts by PA1EJO

    maybe something to review here, It wouldn't show the constellation window for some strange reason

    Turned out a volume mixer issue, still the performance under W7 is nothing compared to hsmodem running under W10, the 5 files and the html were transferred successfully on W10 but not on W7.

    On windows 7 this will not work, that was my other problem :-)

    Will try it, thanks

    Some observations:

    • FT4 works fine as well, but discipline that PC clock as well with a NTP link, the FT4 decoder is less time tolerant
    • FT4/FT8 can easily co-exist in the same part of the band, there was no problem with that last night.
    • No more spurious signals seen last night, I guess everyone understands that the audio drive has to go down.
    • Updated my blog with an ICOM transceiver specific issue, if you find more of these then please comment

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    Did a test last night with the Leila system, what I think is that the warning system is triggered by narrow banded signals in the SSB 2700 Hz window. Narrow banded in this context means that Leila performs the power measurement over a much narrower part in the window than the 2700 Hz (or so) that we use for SSB.


    The consequence is that you can transmit with the same power, but that a poor equalization of the transmitted power will trigger Leila. Too much bass or treble and Leila goes off, Equalize the same power and Leila stays silent. Whistle in the microphone and Leila becomes active. Insert a CW tone with the same transmit power and Leila is triggered again.


    I fully understand that we should stay at acceptable power levels but in the current implementation Leila is more of a power density monitor than a power meter. Power metering should consider what we use for SSB in my opinion. Otherwise you are penalizing users for poor modulation rather than excessive transmit power. What did the makers of the Leila system want to achieve? Where is the pass-band aspect in your power measurement? What does it mean, stay below the level of the beacon, in an acceptable SSB band or in a different band, what width are we talking about? Or did you also want to warn users that they are splattering?


    Please don't start the full duplex discussion again, yes I do that myself in both my permanent and my portable setup. We see Leila and act and this is how you find out how we believe Leila works.

    PA1EJO The satellite LEILA beacons are injected from AMSAT-DL HQ in Bochum.

    This confirms my suspicion because of the factor 0.814 that I mention in the blog. I get the best match between my own Doppler frequency offset measurements and the PSK beacon frequency offsets when I apply the 0.814 to both the PSK beacon measurement and my own Doppler measurement. In other words, the PSK and beacon signals must go through the same 2.4 GHz uplink in the same way as I do the roundtrip measurement. My last point is, why not apply the approx -70 Hz offset on the ground so that you only get to see the Doppler from the satellite?

    This is why I make my own ground stations where I insert a signal splitter and a isolator in the receive line, the second signal of the splitter goes into a SDR and SDRconsole on a laptop, the first signal of the splitter goes to the transceiver

    This thread is ancient, but nevertheless: You can monitor frequencies of the satellite oscillator yourself with a round trip measurement experiment. I found this: https://pa1ejo.wordpress.com/2…00-satellite-transponder/ My verdict is : -63.7 Hz bias for the satellite oscillator and -6 Hz for relativity. The rest of the frequency offsets correspond the Doppler effect due to satellite orbit dynamics and some maneuvering which you get from the TLEs. The satellite beacon is according to me an injected signal from Doha in Qatar, and I think there is a reason to keep the total Doppler and oscillator effect negative, so that you can't have a confusion on the sign of the correction.

    When you specify phase noise, at what offset frequency do you want the -90dBc/Hz?