Hi Marco a case of "never mind the theory, show me the data " :-))
Jay's plot shows what I was thinking about quite well. Markus's signal is
weaker and suffers fade decode problems, but Stefan's signal is stronger and
shows no fading. I think this is due to the "non-linearity" of the waterfall
display. From experience of my use it only takes a change in strength of
about 3dB to go from "M" to "dogbones". Thus my idea that the fading at
distance is much shallower.....it doesnt make it any less difficult to
decypher, but you may only need another dB or so for fully readable once you
display on the trace.
You can lay off time against improved readability by as somone asked
"stacking" modes, like Wolf used to do. This it does need accurate timing,
and is akin to how amateur astronomers produce such spectacular pictures
with backyard telescopes. CW ops do it as well(!!) ....you know "ur 599 pse
rpt all" :-))
Alan
G3NYK
----- Original Message -----
From: <[email protected]>
To: <[email protected]>
Sent: Tuesday, February 12, 2013 1:30 PM
Subject: R: LF: Was Considerations about wide DX experiments - how slow
should we go?
On the theory hornets cannot fly..
Let's dream again Stefan!
73, Marco IK1HSS
----Messaggio originale----
Da: [email protected]
Data: 12-feb-2013 4.27
A: "[email protected]"<[email protected]>
Ogg: LF: Was Considerations about wide DX experiments - how slow
should we go?
I would agree Alan that on the longer hauls I still see a more rapid
fade pattern but not the couple of mins typical of the shorter hop
stuff - - I sort of got used to "20 mins" for 137Khz on the Transpolar
and Trans Siberian paths into China from Eu, but it was a little more
than "5 mins" at 500Khz - that sort of aligns on what I saw at sea on
the Antarctic/South Atlantic paths on 500 back to Portishead path back
long long ago, and what I have heard from here and Fiji into Oz and NZ
- but I also recall the fades became more vertical and shorter during
the more disturbed periods - again this way very dependant on the path
profile and where it and what it crossed on the Rhum line geomag and
whether it was North/South East West - again cutting across the "lines"
was far more problematic. I still scratch my head to see the MUF map
of the world and how it looks more like a complicated barometric
pressure map with depressions and High pressure areas :-) What I would
do is not to discount the long periods out of hand at 500 - I have a
tingly feeling that dot 30 is as slow as I would go but Ive been proved
wrong countless times :-) What I do know is to date that bar Japan to
Alaska (apart from Canada/USA) no signals have reached the levels that
my old CW ears could decode, and truthfully I dont think they would
ever get to that level at our ERP levels and lack of the salty stuff.
Mind you I would love to set up an MF station here on Maui - Ive
already picked my spot and the tower I would steal (Junction of
Lahaina/Kihei road at South Kihei). Im trying to twist a certain arm
to install MF on our expedition ship, but we dont have a lot of space
for the normal type of array Im used to. We will see Laurence KL
1X/KH62AZT
> From: [email protected]
To: [email protected]
Date: Tue, 12 Feb 2013 01:09:31 +0000
Subject: LF: Re: Considerations about wide DX experiments on 630m and
tonites QRSS-60
Hi Stefan I think that maybe the right approach. I think you may find
that
the "perceived wisdom" on fading rate v QRSS speed is based on
relatively
short paths. I suspect it may well be very different at real DX
range, that
is several hops.......>6000km. There obviously is some sort of a
problem
because the wavelength is much shorter than 136kHz so the phase
changes more
rapidly with ionisation and "apparent refection height" but you need
two
"modes" of nearly equal strength to get extinction. This may not be
so
prevalent at long ranges on 470kHz. The experiment will be very
interesting
if you can start to leave traces on distant grabbers.
Alan
G3NYK
----- Original Message -----
From: "Stefan Schäfer" <[email protected]>
To: <[email protected]>; "Vasily Savchenko" <ua0snv@yahoo.
com>;
"Garry and Linda Hess" <[email protected]>; "Douglas D. Williams"
<[email protected]>; "Andy - KU4XR" <[email protected]>; "Edgar J
Twining"
<[email protected]>
Sent: Monday, February 11, 2013 10:57 PM
Subject: LF: Considerations about wide DX experiments on 630m and
tonites
QRSS-60
> MF !!!!!!!!!!!!!!!!!!!!!!! ;-)
>
> Edgar in Tasmania was recently asking if i have some plans about
DX
> experiments on 630m. Well that is a path of > 16000 km. However we
do not
> have real experience if that is easier than 2200m or rather
impossible.
>
> At least i know that there was not even a single decode by UA0SNV
in my MF
> WSPR and QRSS tests so far, while it is no problem on LF (OK my MF
signal
> is weaker than my LF signal). Thus i would guess that it is much
harder to
> get some traces of a signal on 630m. We will try anyway!
>
> I'm starting to run a QRSS-60 transmission on 476.172 kHz (+- a few
Hz)
> for the night. Maybe someone across the pond will catch something.
We, or
> at least i still have no experience about the QSB problem on very
slow
> QRSS transmissions on MF. It would be interesting to see a
spectrogram.
>
> On air in a few minutes.
>
> 73, Stefan/DK7FC
>
> PS: No, not only beacon transmissions, i've just had a > 1 hour
long CW
> QSO with PA0LCE and DK6SX/p! Also contacts to OK2BVG and S57A.
>
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