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Gary
Can u see a trace there at present, he could be
testing
mal/g3kev
----- Original Message -----
Sent: Saturday, July 31, 2010 7:22
PM
Subject: Re: VLF: DK7FC's 6th VLF kite
experiment
Mal, LF,
I will be watching for Stefan on 6.6kHz +/- 200Hz (not 8.97kHz as you
keep stating) as you may have read in his mails. I will be using a loop &
pre-amp as designed by Jim M0BMU.
Battery is now fully charged & system ready to go.
73
Gary - G4WGT.
On 31 July 2010 16:35, mal hamilton <[email protected]>
wrote:
Stefan
Who
has a RX setup that will be able to look for your signal, I seem to
be
the only one so far. There is a trace on 8.97 at present but noone
else can
see it.
There is very little response via this reflector and
vy little acty at
present on 137 and 500.
de mal/g3kev
----- 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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