Message-ID: <002201cb30b2$030fcc30$0401a8c0@xphd97xgq27nyf>
From: "mal hamilton" <g3kevmal@talktalk.net>
To: <rsgb_lf_group@blacksheep.org>
References: <CD23FAD2-C25C-4491-B7A6-66370074F9DB@hurontel.on.ca>	<AANLkTi=-0nwKg3SiO683YX4Wo5oq5aQ74aE5pSbbyv02@mail.gmail.com>	<4C51FA69.1030202@iup.uni-heidelberg.de>	<AANLkTi=pxmqqQmySJ=LHuphU+q1ni+jMSczUSp=m8agv@mail.gmail.com>	<AANLkTikOqWtr7wecaXmzjVZauERuNNuFDpBz7uhAEaSw@mail.gmail.com> <AANLkTikUcSDQyzvYm78aDYX5KnRxy91hkh48b4k7LYhm@mail.gmail.com> <4C529C6B.9070908@iup.uni-heidelberg.de> <4C53EB92.4000806@legal-medicine.de> <4C53F284.7070307@iup.uni-heidelberg.de>
Date: Sat, 31 Jul 2010 14:12:21 +0100
MIME-Version: 1.0
Subject: Re: VLF: DK7FC's 6th VLF kite experiment
Content-Type: text/plain;
	charset="iso-8859-1"
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
Content-Transfer-Encoding: quoted-printable







Stefan
I will look for u on 8.87 tomorrow. I use 0.5 mH inductance on 137 kcs=
 with
my antenna and will work out the Inductance to resonate at 9 kcs
de mal/g3kev

----- Original Message -----
From: "Stefan Sch=E4fer" <schaefer@iup.uni-heidelberg.de>
To: <rsgb_lf_group@blacksheep.org>
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 brid=
ge
> 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 ou=
t
> where the resonance will be, to solve these open Questions. Of cours=
e,
> 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 fir=
st
> 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. Antenn=
as 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
> >
>