Jim
Can u see any trace on 8.97 at present
mal/g3kev
----- Original Message -----
From: "James Moritz" <[email protected]>
To: <[email protected]>
Sent: Saturday, July 31, 2010 2:38 PM
Subject: Re: VLF: DK7FC's 6th VLF kite experiment
> Dear Stefan, LF Group,
>
> I have been doing some receiving checks <9kHz, and althought the QRN level
> is quite high, the level of man-made noise at my home QTH seems to be much
> lower than during the last set of tests. So I should be able to have quite
> good receiving conditions for DK7FC's tests tomorrow without having to go
to
> a /P location.
>
> Around 6.5kHz there are some weak (n x 50Hz) spectral lines drifting
around,
> and a few more stable lines visible, which may be internal to the PC. This
> is similar to the situation at 8.97kHz, so I am hopeful that at least the
> receiver will be reasonably sensitive ;-)
>
> Good luck with the test tomorrow,
>
> Cheers, Jim Moritz
> 73 de M0BMU
>
> ----- Original Message -----
> From: "Stefan Schäfer" <[email protected]>
> To: <[email protected]>
> Sent: Saturday, July 31, 2010 10:53 AM
> Subject: Re: VLF: DK7FC's 6th VLF kite experiment
>
>
> > Hello Peter,
> >
> > Better say 6,6 +-200 Hz. It is still not certain where the resonance
will
> > be, sorry. There are to many assumtions, estimations and calculations.
> >
> > On 137 kHz the measured C for 100m is 580pF (measured with a RC bridge
and
> > by measuring the L and calculating C). But EZNEC shows a lower C. This
> > could be, since a 100m vertical is not absolutely short against Lambda
and
> > so the sems to occur some impedance transformation which "looks/behaves"
> > like a higherC.
> >
> > On <9 kHz the 100m wire IS short against lambda and so i loose this
> > benefit. There, the actual C is present. The L of my variometer part in
> > the BIG coil is estimated to be 30 mH. Maybe it is even more and the
> > overall L is higher than L(coil)+L(variometer) due to the better
magnetic
> > coupling. So maybe i have less C and more L than thought on 8,97.
> >
> > When doubling the antenna height from 100m to 200m and assuming 5 pF/m
the
> > C is doubled as well. So i thought i will come out at 6,34 kHz
> > (8,97/sqrt(2)). But this may just a rough estimate. EZNEC says the C
> > factor is not 2 but 1,88 so i would come out some 100 Hz above.
> >
> > So the question is:
> > What is the actual antenna C for 100m
> > What is the actual (maximum and average) L
> > What is the C factor when going from 100m to 200m
> >
> > This are many uncertainties and so i didn't want to tap the coil at 70%
of
> > the winding to come back to 8,97 kHz but first just to measure out where
> > the resonance will be, to solve these open Questions. Of course, another
> > important and very interesting issue is propagation in the 46km band!
:-)
> >
> > So, sorry for that coarse frequency range. Maybe the actual QRG will be
> > written here in the reflector and can be seen on my garbber2 but first
> > lets hope for proper WX!
> >
> > 73 and tnx, Stefan/DK7FC
> >
> >
> >
> > Am 31.07.2010 11:23, schrieb pws:
> >> Hi Stefan,
> >>
> >> Question: do you have a realistic guess of the frequency window of your
> >> transmission around 6.5kHz, e.g. +-100Hz?
> >>
> >> You wrote:
> >>
> >>> ....
> >>> on *Sunday, the 1. August*, i will make a new kite experiment.
> >>> ...
> >>> i will transmit at arround *6,5 kHz,
> >>> ...
> >>> Starting time is* 8 UTC*, maybe some time later
> >>> ...
> >>> TX QTH is as usual in JN49IS, 49.77647N 8.699525.
> >>>
> >> Distance is 516km, heading 10deg. to Kiel.
> >>
> >> Just modified the software running at ~17mHz of resolution. Antennas
are
> >> two crossed ferrite loops feeding some BC550 in parallel buffered by
> >> NE5532. Both amplifiers are connected to a M-Audio Audiophile 192
running
> >> at 24 kHz on an Intel Atom 330 "shoe-box" under Linux.
> >>
> >> 73 from Baltic Sea,
> >> Peter
> >>
> >
>
>
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