Hi Roger
Good stuff!
In my recent experiments on 9KHz Earth mode I discovered my laptop's on
board sound card was very noisy particularly when operating off battery.
As a result, I added a quality USB professional audio grade sound card
and discovered that it is much more sensitive than the internal soundcard.
Despite the noise in the older soundcard, I was able to copy PSK31 out
to about 4km from the TX (at 35W), mind you my base is about 0.5km
long... I was able to detect the earth mode signal at over 10km using
the same older noisy card. I suspect if I repeated the experiments with
the new sound card I'd have much better results.
73 Scott
VE7TIL
On 4/27/2011 7:19 AM, Roger Lapthorn wrote:
As an experiment I changed over to my wife's laptop and got immediate
decodes of G6ALB's VLF earth mode signal (3km) at -17dB S/N,
suggesting the issue with lack of decodes may be with my soundcard and
not Andrew's.
1408 -17 -0.6 0.008986 0 G6ALB JO02 47
1410 -17 -0.6 0.008986 0 G6ALB JO02 47
1412 -17 -1.2 0.008986 0 G6ALB JO02 47
1414 -17 -0.8 0.008986 0 G6ALB JO02 47
1416 -17 -0.8 0.008986 0 G6ALB JO02 47
This is a very solid signal on the 80m square single turn vertical
wire loop antenna. Andrew is using 44W to an earth electrode antenna.
73s
Roger G3XBM
--
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