LF: Re: 1.9kHz earth-mode tests today

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Sorry, a better copy of the Spectran screengrab is attached. 

Can anyone advise best settings for 10wpm and QRSS3 please?

73s
Roger G3XBM

On 16 June 2010 22:03, Roger Lapthorn <rogerlapthorn@gmail.com> wrote:

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

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G3XBM    GQRP 1678      ISWL G11088

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

spectran_300m_10wpm_160610big.jpg
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