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  • [G3XBM] 10m WSPR TX at 500mW

    From G3XBM via rec.radio.amateur.moderat@21:1/5 to All on Sat Aug 14 01:02:08 2021
    XPost: rec.radio.amateur.moderated, rec.radio.amateur.space, uk.radio.amateur XPost: free.uk.amateur-radio

    Roger G3XBM's (Mainly) Amateur Radio Blog

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    10m WSPR TX at 500mW

    Posted: 13 Aug 2021 01:57 PM PDT http://g3xbm-qrp.blogspot.com/2021/08/10m-wspr-tx-at-500mw.html


    Since 0822z, I have been on 10m WSPR TX. As yet, nobody has spotted me.
    UPDATE 0840z: Already 4 spots from 2 unique stations. Looks like Es.
    UPDATE 2056z: 26 unique stations spotted me today.


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    6m FT8 QRP (Friday)

    Posted: 13 Aug 2021 02:04 PM PDT http://g3xbm-qrp.blogspot.com/2021/08/6m-ft8-qrp-friday.html


    Since 0822z I have been on 6m FT8. Apart from a very brief TX period at
    2.5W to the V2000 vertical omni with the furthermost a spot by YO8SSB
    (1874km), I have been RX only. So far this morning, 4 stations spotted. Es
    is just starting I think.
    UPDATE 2104z: 179 stations spotted on 6m FT8 RX today as the map shows.


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    Arecibo Observatory and EME

    Posted: 12 Aug 2021 11:50 PM PDT http://g3xbm-qrp.blogspot.com/2021/08/arecibo-observatory-and-eme.html


    Sadly this giant radio telescope in Puerto Rico was damaged beyond repair.

    In the mid 1960s it was used for some amateur moonbounce tests. Many
    amateurs made their first EME QSOs this way. The dish gain was very high
    with a 1000 foot dish! I have no idea what the ERP was.
    This was 1964 (?), way before we had any weak signal modes that makes EME a little easier. EME still needs optimum equipment and is not for those not prepared to work hard.
    I am not sure what is needed these days to work the better stations via
    EME, but I would guess at least 100W, mast head preamps and as big a yagi
    array as you can manage. This also requires accurate moon tracking, low
    cable losses and weak signal modes optimised for EME.

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    Tunnel diodes

    Posted: 12 Aug 2021 11:48 PM PDT http://g3xbm-qrp.blogspot.com/2021/08/tunnel-diodes.html


    Back in the 1960s these were all the rage. I remember making a simple
    tunnel diode oscillator at university in about 1969.
    I am not sure if you can buy them still. They are 2 pin negative resistance diodes that work by quantum mechanical tunnelling.

    Very simple uW TXs are possible and there was one published that was copied about 200km away in New Zealand on 80m.
    See https://en.wikipedia.org/wiki/Tunnel_diode .
    See
    https://www.rfwireless-world.com/Vendors/Tunnel-diode-manufacturers.html .

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    Sunspots - Friday August 13th 2021

    Posted: 12 Aug 2021 11:48 PM PDT http://g3xbm-qrp.blogspot.com/2021/08/sunspots-friday-august-13th-2021.html


    Solar flux is 74 and the SSN 11 . A=4 and K=2.

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