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No point me testing if noone watching
mal/g3kev
----- Original Message -----
Sent: Saturday, July 31, 2010 7:53
PM
Subject: Re: VLF: DK7FC's 6th VLF kite
experiment
Mal,
Not watching at the moment as Stefan stated his tests would be tomorrow
from about 0800utc.
And due to increased kite antenna length to 200 metres but using same
inductance that the frequency would be lower (ie. 6.6kHz +/- 200Hz)
If you look at his grabber you will see that Stefan is not Txing.
Cheers,
Gary - G4WGT.
On 31 July 2010 19:31, mal hamilton <[email protected]>
wrote:
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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