Hi Stefan, if I can ramble a bit on this topic.......I think the situation
is probably more complex than you are envisaging. I see what your objective
is.....you effectively want to characterise the height of the Earth
ionospher waveguide over the whole path. However you talk of QSB. Now QSB
can only happen on a given route if thereare two paths of different length
between the tx and rx. Thus for example take a 10000km path and think about
rays rather than waveguide modes. The main mode will be about 5 ionospheric
hops, but QSB will occur if there are also signals at the rx which travel by
6 hops. Their phase will be different and will also change differently as
the apparent reflection height changes along the path. Another complication
is that one or both paths may not be a strict great circle due to tilting of
the ionospheric layer.
It may be possible using several source signals to extract parameters of the
path. A UK radio amateur astronomer has done this for very short range paths
using simultaneous data from Anthorn and Skelton to central England .....but
not in real time, and only in daytime when the modelling is easier. Another
problem could be that the apparent reflection heights calculated from
23.4kHz data may be different to those in action for frequencies below 8kHz.
It is an interesting challenge. In daytime you have the added complication
of a narrower "waveguide" It may be possible to model a 1000km path (one
hop), and test it on that.
Alan
G3NYK
----- Original Message -----
From: "DK7FC" <selberdenken@posteo.de>
To: <rsgb_lf_group@blacksheep.org>
Sent: Tuesday, November 15, 2016 8:22 PM
Subject: Re: VLF: EbNaut transmissions on lower frequencies?, pre-tests:
6.47kHz
Hi Paul,
Many thanks for the decodes from these streams. What is the most distant
location from where a stream is available?
Interestingly, the phase of my signal is less stable in Bielefeld than on
your side. OK, it can be expected but now we saw it.
So maybe this is an advantage of more distant locations? I remember the
VLF grabber of TF3HZ, who received my kite transmission on 8.97 kHz. Maybe
he will join in again and even provides a stream? The distance would be
2440 km.
Probably he is reading this, i would expect :-)
The (unknown) phase stability over a certain path and time is the
question. And its reproducibility.
It looks like we started something here, a thing that could become the
trick how to get world wide VLF communication by amateur radio stations.
You see i become a bit crazy now ;-)
Edgar J. Twining is the man i'm thinking about! I know he has the skills,
motivation and RX sites to be the man for the unbelivable project. Maybe
he is reading this as well.
Now a next question/idea comes up to me: When observing the phase of
available signals (DHO38, GBZ, JXN, ALPHAs...), can we conclude to the
phase on 6.47 kHz? I mean daily!
Assume we would try to transfer a message to Australia by using the
currently tested technique. Then there will be 'good' and 'not so good'
days. Not only different QRN levels, also phase changes may become a
problem. If someone, let's say in Tasmania, would run a wideband RDF
spectrogram (yes Markus, i know. I will do it soon! Now the time has
come!) and can monitor the phase of DHO38 on 23.4 kHz, is this of any use
for 6.47 kHz or 8.27 kHz??
At least it would be most useful to observe the VLF spectrum from there,
trying to find some correlations. We need an expert there!
The linux commands and your vlf utils are a future project for me. It will
be a big project i assume. But maybe its better to let me be the one on
the TX side.
Am 14.11.2016 20:09, schrieb Paul Nicholson:
11th Nov 3.9 -62.5 -141.2 8K19A 60 4 'TEST'
12th Nov 4.9 -59.7 -134.3 8K19A 60 4 'TEST'
11th + 12th 6.6 -58.1 -137.5 8K19A 60 4 'TEST'
13th Nov 8.5 -55.6 -138.5 8K19A 60 4 'TEST'
11th to 13th 8.6 -55.2 -137.8 8K19A 60 4 'TEST'
14th 3.5 -61.3 -136.8 8K19A 60 4 'TEST'
11th to 14th 9.9 -54.3 -137.6 8K19A 60 4 'TEST'
Thanks for the table.
What's the result of 15 th and 11th to 15 th on your side?
Its better not to mix up the day and night transmissions now. The night
transmissions are a separate experiment. But if their phase is stable as
well, one could correct the phase offset and use them for a decode. So we
can simply avoid the time where QSB and the Terminator passes the path. To
be checked...
73, Stefan
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