Hi Stefan,

Amazing work on ULF.  This is very inspring for for someone lamenting
over yet another fried VLF helix.  Undaunted, I've sought more wire
to wind a new one.

It is easy to lock to NAA and maybe generate a carrier on 8277 Hz?
During the detection of the far field for the first time on 18 April,
the Alpha stations could be seen in the 11 kHz window.  Incidently I
was using the DK7FC VLF probe.

73
Joe

On Mon, 24 Apr 2017, DK7FC wrote:

Hi Joe,

You could generate a separate (maybe locked to NAA) spectrogram from a local probe to check if everything worked fine from the transmitter site. I always found my feedback signal from the local tree grabber most useful, i'm even feeling blind if it is not available :-)

73, Stefan

Am 24.04.2017 15:52, schrieb [email protected]:

I really enjoyed that, Paul.  Thank-you.

The ice is finally melting and it may be possible to raise
the aerial this evening.  I will advise when the VLF TX is QRV again.

73 to all
Joe VO1NA

On Sun, 23 Apr 2017, Paul Nicholson wrote:

Is that recorded with antenna direct into soundcard
(metaphorically speaking ) ?

Yes.  There's no frequency shift, just amplification of
the audio frequencies present on the E-field probe.

Not even that much amplification, on the order of x50 voltage
gain before the soundcard (which needs 4 volts for full scale).
The only post processing is hum notching, 5 pole high pass
at 300 Hz and 3 pole low pass at 10kHz.

--
Paul Nicholson
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