Dear Jim, Chris, dreamers,
very happy to read this, well done both!
I had shifted the display range of my grabber a few times to your frequency,
but unfortunately no traces in Bavaria yet. However I believe this will be
feasible on a quiet day, given your estimated radiated power and a long
stabilized carrier.
Wishing the best of luck, and a happy new year to all in the group,
Markus (DF6NM)
From: James Moritz
Sent: Friday, December 31, 2010 6:45 PM
To: [email protected]
Subject: Re: LF: VLF - G3XIZ
Dear Chris, LF Group,
The signal disappeared some time around 1520utc - the complete trace is
shown in the attachment.
I made an estimate of the field strength of your signal by injecting a test
signal at a known EMF into the loop antenna, and comparing with the level of
your signal. The received FS at the strongest point (around 1330utc) worked
out to be 1.8uV/m. Taking the distance between our locations as 37km, your
ERP would have been 87uW. The SNR at best was around 15dB, making the noise
level 0.32uV/m in the FFT noise bandwidth of 2.1mHz, or a noise density of
7uV/m per sqrt(Hz)
Assuming a 50m vertical wire (heff ~ 25m), Rrad of your antenna at 8.97kHz
would be 880micro-ohms. Assuming 2.62dB directivity for an electrically
short monopole compared to a dipole, and Iant of 200mA, the calculated value
of ERP would then be 64uW. So there is reasonable agreement between these
two calculations, the difference only being 1.3dB.
Thanks for the tests,
Cheers, Jim Moritz
73 de M0BMU
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