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New (Moonbounce) WSJT-X "Echo" mode

Discussion in 'Working Different Modes' started by AA5CT, Sep 11, 2019.

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  1. AA5CT

    AA5CT Ham Member QRZ Page

    Just curious if anyone has tried the new WSJT-X "Echo" mode on any of the SW or MW bands?

    This mode is described to operate this way from:

    https://physics.princeton.edu/pulsar/K1JT/wsjtx-doc/wsjtx-main-2.1.0.html#_echo_mode

    Excerpt:
    ---------------------------------
    8.7. Echo Mode
    Echo mode allows you to make sensitive measurements of your own lunar echoes even when they are too weak to be heard. Select Echo from the Mode menu, aim your antenna at the moon, pick a clear frequency, and toggle click Tx Enable. WSJT-X will then cycle through the following loop every 6 seconds:

    1. Transmit a 1500 Hz fixed tone for 2.3 s

    2. Wait about 0.2 s for start of the return echo

    3. Record the received signal for 2.3 s

    4. Analyze, average, and display the results

    5. Repeat from step 1
    --------------------------------
     
  2. N3DT

    N3DT Ham Member QRZ Page

    I think you'll find this only works with 2M and up. Not on HF And you'll still need a good antenna and plenty of power.
     
    K0UO likes this.
  3. AA5CT

    AA5CT Ham Member QRZ Page

    Can you point me to the "test case" where it failed?

    For instance, I've observed a Doppler shifted 'reflection' from heavy rainfall and a rapidly advancing storm front at VHF using a VORTAC (a/c VOR station) as a source before, something I'm sure most hams would jump up immediately and say "No, not possible."

    (Maybe you're not considering we can work at SNRs far below zero today?)
     
  4. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    You aren't going to get a return signal from the moon on HF using amateur power and amateur antennas.

    -That is why you don't see any HF EME awards. The technical reasons have been discussed before in the satellite/EME forums. The path losses are immense, and the moon surface is not a good HF RF reflector.

    -The description states the software waits the equivalent time for EME round circuit time. So you can't use the software to detect a signal any closer than an object at the distance of the moon.

    -The HAARP facility in Alaska performed an HF EME test about seven years ago around 7 Mhz. However they were using an array of over one hundred gain antennas and Megawatts of power.
     
    K0UO likes this.
  5. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Key words "VHF".

    1. VHF is not HF
    2. The minor doppler shift you saw at VHF would have been reduced 1/6 or more at HF frequencies (pick a frequency for specifics).
    3. Moon bounce does not use doppler shift. Actually doppler shift is undesirable, but a known confounding factor for EME.
    4. Again, the moon is a very poor HF reflector.
    5. Ionospheric absorption losses are much higher for HF
    6. Ionospheric refraction of HF makes reliable pointing unpredictable
     
    Last edited: Sep 11, 2019
    K0UO likes this.
  6. AA5CT

    AA5CT Ham Member QRZ Page

    Duh. You didn't get the point.
     
  7. KA0HCP

    KA0HCP XML Subscriber QRZ Page

    Well you are the one who didn't communicate the point you intended. (and using fifth grade vernacular doesn't help).

    Make your point in a different way, please.
     
  8. AA5CT

    AA5CT Ham Member QRZ Page

    Another "Duh" regarding round-trip times. Did you REALLY figure it was necessary to point this out? I'm really disappointed at times, do I have to, each time I post here, have to layout my experience and technical level?

    Still looking for the 'technical case', w/numbers. A google search isn't showing much yet.
     
  9. AA5CT

    AA5CT Ham Member QRZ Page

    Its not worth the trouble on this point. Either you got it, or you didn't.
     
  10. AA5CT

    AA5CT Ham Member QRZ Page

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