5 Oct 2019

Return to 472kHz WSPR

After quite a break, I am back on 472kHz WSPR TX (very low ERP) and RX.

I wound a new matching transformer (shown in photo) in the hope of squeezing a tiny bit more ERP from my earth-electrode "antenna" in the ground. I will calculate the ERP tomorrow, but I don't think it is greater. The coil has more turns on the secondary, but I think the tapping point was not far off before.

My own signal has been copied by a couple of stations and G1GKN (99km) has been copied here a few times. I shall leave it on this evening and possibly overnight.

472kHz WSPR so far this evening
It would be good to try FT8 on 472kHz (about 10dB worse than WSPR), but I am not sure if people use FT8 on MF. Years ago I had some JT9 QSOs on MF.

UPDATE 1852z: Best DX so far on 472kHz WSPR RX is LA3EQ (769km) running 20mW ERP.

UPDATE 2108z: A few new stations spotted this evening, that I did not see last season: LA4NJ (800km) and DL1HWK (816km). I don't think these stations were active last season,
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1 comment:

  1. Jan Lustrup LA3EQSun Oct 06, 06:42:00 am GMT+1

    Hi Roger,

    Mistery doubble spots…

    I see you are back on 630meters.
    Here is what i copied from you last night. The strange thing is you where decoded twice in each period on two seperate frequencies.
    I see they are 2.8kHz a part and have the same signal strength.

    2019-10-06 01:28 G3XBM 0.478483 -30 0 JO02dg LA3EQ JO28xj 769 25
    2019-10-06 01:28 G3XBM 0.475683 -30 0 JO02dg LA3EQ JO28xj 769 25
    2019-10-06 03:20 G3XBM 0.475683 -30 0 JO02dg LA3EQ JO28xj 769 25
    2019-10-06 03:20 G3XBM 0.478483 -30 0 JO02dg LA3EQ JO28xj 769 25
    2019-10-06 05:02 G3XBM 0.475681 -30 0 JO02dg LA3EQ JO28xj 769 25
    2019-10-06 05:02 G3XBM 0.478481 -30 0 JO02dg LA3EQ JO28xj 769 25

    After a lot of thinking ( & two cups of strong coffee) I found out that I was running two wspr programs, both audio input channels listning to the same rig (TS-2000 & miniwhip antenna), but the second rig (IC-7100 under CAT Control & inverted "L" antenna) was tuned to 477Khz for Opera 8.

    477 - 474,2 = 2.8kHz!


    So there is nothing wrong with your transmitter. My mistake, sorry.

    73's Jan LA3EQ

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