Re: Re: VLF: DK7FC's 8th VLF kite experiment

[Roger Lapthorn <rogerlapthorn@gmail.com>]

Stefan,

The possibility of whistler duct AMATEUR propagation is fascinating. There are (I think) spectrograms of such propagation from NAA (~14kHz) back in the 1965 book "Whistlers and Related Ionospheric Phenomena" by J.A.Hellliwell (I have a copy). This could mean signals getting to, for example, conjugate locations in the southern hemisphere (S.Africa?) with relatively low attenuation. A chirped signal would also show whisper dispersion I guess.

You will need some grabbers in distant places!

73s
Roger G3XBM

2010/10/26 Stefan Schäfer <schaefer@iup.uni-heidelberg.de>

Dear VLF,

Attached you find the results of Paul Nicholson of my 8th VLF experiment. Interesting links and he seems to confirm that my frequency is pretty accurate now ;-)
Furthermore the first part gives an idea of future planned VLF tests i hope to do on my earth antenna :-)

73, enjoy,

Stefan7DK7FC

-------- Original-Nachricht --------

Betreff:	Re: VLF: DK7FC's 8th VLF kite experiment
Datum:	Tue, 26 Oct 2010 20:10:58 +0000
Von:	Paul <paul@abelian.netcom.co.uk>
An:	Stefan Schäfer <schaefer@iup.uni-heidelberg.de>
CC:	Markus Vester <markusvester@aol.com>, Wolfgang Büscher <dl4yhf@freenet.de>, Renato Romero <contact@vlf.it>

Hi Stefan, et al

My report of your test on Saturday is below.

> What do you think about a test on the earth antenna,
> this week?

We should have a good think about what tests would be
useful to do.  For example, to measure the propagation
delay using a chirped transmission (this would move us
a step closer towards the goal of putting a signal
through a whistler duct).  I am probably too far away
to take part in such a test.

First transmission 2010-10-23_08:03, 3600 seconds
-------------------------------------------------
Background @ 8970:  http://abelian.org/vlf/ss101023/noise8970.png
Before sferic blanking: http://abelian.org/vlf/ss101023/tx1a.png
After sferic blanking: http://abelian.org/vlf/ss101023/tx1b.png
Average frequency: 8969.974924 Hz +/- 1uHz

Absolute phase, measured in 5 minute blocks over 50 minutes:
 -151.049
 -137.833
 -143.681
 -113.856
 -112.387
 -131.829
 -117.567
 -133.994
 -137.574
 -119.973
Suggests the transmitter phase is switching between 2 values,
about 20 degrees apart.  Spectrum shows some weak sidebands.

Second transmission 2010-10-23_10:33, 1680 seconds
--------------------------------------------------
Background @ 6470:  http://abelian.org/vlf/ss101023/noise6470.png
Before sferic blanking: http://abelian.org/vlf/ss101023/tx2a.png
After sferic blanking: http://abelian.org/vlf/ss101023/tx2b.png
Average frequency: 6469.974916 Hz +/-1uHz

Absolute phase, measured in 5 minute blocks over 25 minutes:
 -141.539
 -153.483
 -150.903
 -155.623
 -157.098

Third transmission 2010-10-23_13:21, 2220 seconds
-------------------------------------------------
Background @ 5170:  http://abelian.org/vlf/ss101023/noise5170.png
Before sferic blanking: http://abelian.org/vlf/ss101023/tx3a.png
After sferic blanking: http://abelian.org/vlf/ss101023/tx3b.png
Average frequency: 5169.999969 Hz +/-1uHz

Notes
-----
The spike in the 8970Hz noise chart at 16:05 is the current injection
calibrator and at 16:30 the gain of the E/W loop was adjusted.  Vertical
scale refers to the calibration before the gain change.

The average frequencies are all on the low side, by between
6ppb and 12ppb.
--
Paul Nicholson
--

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