LF: 1.9kHz earth-mode tests today

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Today I modified my 4W VLF transmitter so it could send either a 10 wpm or QRSS3 
beacon signal. I also went out into the fields with my loop/preamp and a
 PC with Spectran to 
receive it. For the first attempt with a PC I went 0.3km away from home 
where the 4W signal from the earth electrode "antenna" could clearly be 
received by ear. With Spectran I could read the 10wpm CW signal with 
20dB S/N in a 12Hz bandwidth, if my understanding of the Spectran 
settings is right. There is an audio
 recording here so you can judge the S/N yourselves. This suggests 
that with QRSS3 (or slower still) and really screwing the bandwidth down I should be able 
to do much better. My problem is knowing how to calibrate the soundcard 
etc and clearly I need a more stable source than my free running 
twin-tee audio oscillator.
I am a total novice when it comes to using QRSS and soundcards using very narrow bandwidths.

73s
Roger G3XBM

-- 
http://g3xbm-qrp.blogspot.com/
http://www.g3xbm.co.uk
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G3XBM    GQRP 1678      ISWL G11088

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