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Date: Mon, 2 Aug 2010 05:18:30 -0700 (PDT)
From: Dave Pick <davepick@btinternet.com>
To: rsgb_lf_group@blacksheep.org
In-Reply-To: <4C56A58C.8020600@iup.uni-heidelberg.de>
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Subject: Re: VLF: DK7FC's 6th VLF kite experiment
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Well done Stefan!

Nothing seen in Birmingham I'm afraid but, as you say, the noise level=C2=
=A0seemed=20
quite high.
Your report reminded me of my first trips to North Scotland with the kite=
=20
antenna on 136kHz.
Watch out for static charged rain!....

73
Dave G3YXM



________________________________
From: Stefan Sch=C3=A4fer <schaefer@iup.uni-heidelberg.de>
To: rsgb_lf_group@blacksheep.org; Paul <paul@abelian.netcom.co.uk>; Renato=
=20
Romero <contact@vlf.it>; Bernd Grupe <bernd.grupe@t-online.de>
Sent: Monday, 2 August, 2010 12:01:32
Subject: Re: VLF: DK7FC's 6th VLF kite experiment

Dear LF/VLF group,

Many thanks to all the people who tried to catch may signal in the yesterd=
ays=20
test! Thanks for taking the time to watch the QRG on a sunny sunday! The=
 RX side=20
is an important factor in such a experiment because it motivates the TX si=
de=20
when there is no QSO but just a reception. It makes me glad that there is=
 such=20
an interest in those tests.
Special thanks to Paul Nicholson who did the effort to re-arrange his ante=
nna=20
and software and the website with a nice overview.=20

Also special thanks to Markus/DF6NM for the telephone support about the ac=
tivity=20
on the reflector, the lightning situation and the QRN situation. This is=
 an=20
important feedback as well and much more interesting than just having a mo=
bile=20
internet stick.

Congratulations to all the successful receiving stations! It was a test in=
 the=20
middle of the summer time with heavy QRN. The QRN was on its daily maximum=
 as i=20
was able to transmit at a high kite angle. The QRN was even high compared=
 to the=20
last days during that time (still comparable in my DFCW-6000/8,97 window=
 on the=20
grabber1). So, there is MUCH potential to get a much better S/N in the win=
ther=20
period and at better wind situations. Thus, i am very hopefully that e.g.=
 Jim=20
and Paul will catch that signal! This makes the following experiment an=20
optimistic challenge! I am even sure that it will be possible to go down=
 in the=20
DFCW-mode, maybe to DFCW-60. This makes it possible to try a cross band QS=
O (!)=20
like 137kHz/6,47 kHz (or 8,97 first). Here i could use a small portable ac=
tive=20
antenna for 137 that will not be too much swayed be the TX antenna...

As far as i can see there was a positive reception at least by the followi=
ng=20
stations:
DF8ZR (QRSS-60 mode, 16km)
DK7FC (grabber in DFCW-240 mode, 40km)
DD7PC (congrats, first time! 53km)
DF6NM (insecure, fragments, 180km)
DL4YHF(impressive S/N!, 264km) Best DX reception of the lowest signal,=20
transmitted by an amateur so far (far field)

Paul Nicholson told me that he has recorded the siganl and will try to wor=
k the=20
trace out. Let's be excited about his proffessional and nice to read repor=
t!


Now, i want to give a detailed report of the things that happened on the=
 TX=20
side:

I arrived at about 9:40 UTC. It was no problem to arrange the equipment an=
d=20
nothing was forgotten. Just before, the rain stopped but the wind was a li=
ttle=20
to weak.
I used the 8,1m^2 kite but it took some hours until the wind was enough,=
 sadly.=20
First, the wind increased just for some minutes. In that time i saw that=
 the=20
wire was to long and was sagging to much.=20


After cutting some meters i could start the generator and PA and turned th=
e VFO=20
wheel down until i saw a peak on the amperemeter. It was on 5,7 kHz but it=
 was=20
due to a very low kite angle. Later, as the wind increased i could do more=
=20
useful resonating tests. I found that i can resonate between about 6,4 kHz=
 to=20
6,6 kHz. Maybe this is due to the fact that the wire has to be slighty lon=
ger=20
than 200m since the kite braid is elastic and will be 20m (10%) longer at=
 strong=20
wind.
After watching the 6,5 kHz sector in the last weeks i found that it is bes=
t to=20
transmit not on n*50 Hz or n*16,6667 Hz (frequency of the german trains gr=
id).=20
Thus i decided to go about into the center, to 6470,00 Hz, within the 46=
 km=20
band! :-)
First it was not possible to transmit a real "message" since the wind was=
 OFF=20
sometimes :-(. My plan was to transmit "CU" in DFCW-600.

Than, an accident happened: Suddenly the was was off and i wasn't fast eno=
ugh to=20
bring the kite down on the road. So the 200 =E2=82=AC kite dropped in a 15=
m high tree! I=20
felt like a child that lost his parents on the airport! I was not strong=
 enough=20
to pull it out there with its braid. I saw no other way to try it with the=
 car,=20
even when the kite gets damaged with this attempt. So i fastened the braid=
 on=20
the car and drove some 10m until there was a heavy pull on it. The braid=
 stopped=20
in a beginning corner of a corn field and as i lifted it above the corn it=
=20
sounded like a lash/whip. But suddenly the kite came out of the tree and=
 before=20
it dropped on the bottom it was caught by the wind and rised into the sky,=
=20
hanging on my car :-) I drove back the the TX coil with the kite on the ca=
r...

After taking too much sun and after this stress i was powerless and not=20
motivated to improve the earth losses and so on but it was my absolute goa=
l to=20
produce some nice signals for the RX stations, at least a limple carrier!=
 So i=20
set up the whole arrangement and now the wind was stable, lifting the kite=
=20
continously above 45 deg, sometimes 70 deg. In proper wind conditions, it=
 is=20
lifted to 70...80 deg.
The antenna current was about 750mA and after connecting the copper rod i=
=20
hammered into the soil in the 5th experiment it rised to 800mA. Then i red=
uced=20
the primary winding number from 70 to 60. Then, the current was up to 920=
 mA,=20
the highest current so far. Just before 16 UTC the fuel of the generator=
 was=20
empty and my fuel as well ;-) That was the end of the 6th experiment.

So, my overall losses are about 600 Ohm now. The ERP was about 11mW and th=
e=20
voltage just about 20 kV rms. I am sure to be able to decrease the earth=
 losses=20
to 200 Ohm and the coil losses will be reduced to 200 Ohm as well since i=
 can=20
reduce the L to come back to 8,97 kHz.

Now i know the C of the wire and can make a reasonable tap on the coil, at=
=20
arround 275 mH! So, in the 7th experiment i can transmit on 6,47 kHz as we=
ll as=20
on 8,97 kHz. I just have to change the coil connection and the VFO frequen=
cy and=20
that can be done in < 2 minutes.

I will spend some experiments on this 200m antenna now before going to 300=
m. And=20
i want to test it on 137 kHz ;-) With a 300m antenna, i will explore the=
 58km=20
band in future tests! Also, just for fun,=C2=A0 i want to transmit on 7355=
 Hz. This=20
frequency is a message in it selfe for amateurs ;-)

So, all in all it was a hard experiment with many difficulties and the QRN=
=20
situation could have been at least 15 dB better but it was an important te=
st to=20
find the tap for the L to come back on the Dreamers Band (33km) with a 200=
m=20
vertical. Also we have done some new record receptions and can be very hop=
efully=20
that this can be much improved in the next test, if there is proper wind=
 and=20
less QRN that can be assumed when going to the autumn :-)

Again thanks to all the group and hope cuagn in the next test! :-)

Best 73, Stefan/DK7FC

PS: Some photos and screenshots will be displayed on my QRZ.com page in so=
me=20
days.

PPS: Hopefully there will come up further stations on the dreamers band wi=
thin=20
this year :-)

--0-353836496-1280751510=:77885
Content-Type: text/html; charset=utf-8
Content-Transfer-Encoding: quoted-printable

<html><head><style type=3D"text/css"><!-- DIV {margin:0px;} --></style></h=
ead><body><div style=3D"font-family:times new roman, new york, times, seri=
f;font-size:12pt"><DIV>Well done Stefan!</DIV>
<DIV>&nbsp;</DIV>
<DIV>Nothing seen in Birmingham I'm afraid but, as you say, the noise leve=
l&nbsp;seemed quite high.</DIV>
<DIV>Your report reminded me of my first trips to North Scotland with the=
 kite antenna on 136kHz.</DIV>
<DIV>Watch out for static charged rain!....</DIV>
<DIV><BR>73</DIV>
<DIV>Dave G3YXM</DIV>
<DIV style=3D"FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, tim=
es, serif"><BR>
<DIV style=3D"FONT-SIZE: 12pt; FONT-FAMILY: times new roman, new york, tim=
es, serif"><FONT face=3DTahoma size=3D2>
<HR SIZE=3D1>
<B><SPAN style=3D"FONT-WEIGHT: bold">From:</SPAN></B> Stefan Sch=C3=A4fer=
 &lt;schaefer@iup.uni-heidelberg.de&gt;<BR><B><SPAN style=3D"FONT-WEIGHT:=
 bold">To:</SPAN></B> rsgb_lf_group@blacksheep.org; Paul &lt;paul@abelian.=
netcom.co.uk&gt;; Renato Romero &lt;contact@vlf.it&gt;; Bernd Grupe &lt;be=
rnd.grupe@t-online.de&gt;<BR><B><SPAN style=3D"FONT-WEIGHT: bold">Sent:</S=
PAN></B> Monday, 2 August, 2010 12:01:32<BR><B><SPAN style=3D"FONT-WEIGHT:=
 bold">Subject:</SPAN></B> Re: VLF: DK7FC's 6th VLF kite experiment<BR></F=
ONT><BR>Dear LF/VLF group,<BR><BR>Many thanks to all the people who tried=
 to catch may signal in the yesterdays test! Thanks for taking the time to=
 watch the QRG on a sunny sunday! The RX side is an important factor in su=
ch a experiment because it motivates the TX side when there is no QSO but=
 just a reception. It makes me glad that there is such an interest in thos=
e tests.<BR>Special thanks to Paul Nicholson who did the effort to re-arra=
nge his antenna and
 software and the website with a nice overview. <BR>Also special thanks to=
 Markus/DF6NM for the telephone support about the activity on the reflecto=
r, the lightning situation and the QRN situation. This is an important fee=
dback as well and much more interesting than just having a mobile internet=
 stick.<BR><BR>Congratulations to all the successful receiving stations!=
 It was a test in the middle of the summer time with heavy QRN. The QRN wa=
s on its daily maximum as i was able to transmit at a high kite angle. The=
 QRN was even high compared to the last days during that time (still compa=
rable in my DFCW-6000/8,97 window on the grabber1). So, there is MUCH pote=
ntial to get a much better S/N in the winther period and at better wind si=
tuations. Thus, i am very hopefully that e.g. Jim and Paul will catch that=
 signal! This makes the following experiment an optimistic challenge! I am=
 even sure that it will be possible to go down in the DFCW-mode, maybe to=
 DFCW-60.
 This makes it possible to try a cross band QSO (!) like 137kHz/6,47 kHz=
 (or 8,97 first). Here i could use a small portable active antenna for 137=
 that will not be too much swayed be the TX antenna...<BR><BR>As far as i=
 can see there was a positive reception at least by the following stations=
:<BR>DF8ZR (QRSS-60 mode, 16km)<BR>DK7FC (grabber in DFCW-240 mode, 40km)<=
BR>DD7PC (congrats, first time! 53km)<BR>DF6NM (insecure, fragments, 180km=
)<BR><B>DL4YHF(impressive S/N!, 264km)</B> Best DX reception of the lowest=
 signal, transmitted by an amateur so far (far field)<BR><BR>Paul Nicholso=
n told me that he has recorded the siganl and will try to work the trace=
 out. Let's be excited about his proffessional and nice to read report!<BR=
><BR><BR>Now, i want to give a detailed report of the things that happened=
 on the TX side:<BR><BR>I arrived at about 9:40 UTC. It was no problem to=
 arrange the equipment and nothing was forgotten. Just before, the rain st=
opped but
 the wind was a little to weak.<BR>I used the 8,1m^2 kite but it took some=
 hours until the wind was enough, sadly. First, the wind increased just fo=
r some minutes. In that time i saw that the wire was to long and was saggi=
ng to much. <BR><BR>After cutting some meters i could start the generator=
 and PA and turned the VFO wheel down until i saw a peak on the amperemete=
r. It was on 5,7 kHz but it was due to a very low kite angle. Later, as th=
e wind increased i could do more useful resonating tests. I found that i=
 can resonate between about 6,4 kHz to 6,6 kHz. Maybe this is due to the=
 fact that the wire has to be slighty longer than 200m since the kite brai=
d is elastic and will be 20m (10%) longer at strong wind.<BR>After watchin=
g the 6,5 kHz sector in the last weeks i found that it is best to transmit=
 not on n*50 Hz or n*16,6667 Hz (frequency of the german trains grid). Thu=
s i decided to go about into the center, to 6470,00 Hz, within the 46 km=
 band!
 :-)<BR>First it was not possible to transmit a real "message" since the=
 wind was OFF sometimes :-(. My plan was to transmit "CU" in DFCW-600.<BR>=
<BR>Than, an accident happened: Suddenly the was was off and i wasn't fast=
 enough to bring the kite down on the road. So the 200 =E2=82=AC kite drop=
ped in a 15m high tree! I felt like a child that lost his parents on the=
 airport! I was not strong enough to pull it out there with its braid. I=
 saw no other way to try it with the car, even when the kite gets damaged=
 with this attempt. So i fastened the braid on the car and drove some 10m=
 until there was a heavy pull on it. The braid stopped in a beginning corn=
er of a corn field and as i lifted it above the corn it sounded like a las=
h/whip. But suddenly the kite came out of the tree and before it dropped=
 on the bottom it was caught by the wind and rised into the sky, hanging=
 on my car :-) I drove back the the TX coil with the kite on the car...<BR=
><BR>After taking too
 much sun and after this stress i was powerless and not motivated to impro=
ve the earth losses and so on but it was my absolute goal to produce some=
 nice signals for the RX stations, at least a limple carrier! So i set up=
 the whole arrangement and now the wind was stable, lifting the kite conti=
nously above 45 deg, sometimes 70 deg. In proper wind conditions, it is li=
fted to 70...80 deg.<BR>The antenna current was about 750mA and after conn=
ecting the copper rod i hammered into the soil in the 5th experiment it ri=
sed to 800mA. Then i reduced the primary winding number from 70 to 60. The=
n, the current was up to 920 mA, the highest current so far. Just before=
 16 UTC the fuel of the generator was empty and my fuel as well ;-) That=
 was the end of the 6th experiment.<BR><BR>So, my overall losses are about=
 600 Ohm now. The ERP was about 11mW and the voltage just about 20 kV rms.=
 I am sure to be able to decrease the earth losses to 200 Ohm and the coil=
 losses will
 be reduced to 200 Ohm as well since i can reduce the L to come back to 8,=
97 kHz.<BR><BR>Now i know the C of the wire and can make a reasonable tap=
 on the coil, at arround 275 mH! So, in the 7th experiment i can transmit=
 on 6,47 kHz as well as on 8,97 kHz. I just have to change the coil connec=
tion and the VFO frequency and that can be done in &lt; 2 minutes.<BR><BR>=
I will spend some experiments on this 200m antenna now before going to 300=
m. And i want to test it on 137 kHz ;-) With a 300m antenna, i will explor=
e the 58km band in future tests! Also, just for fun,&nbsp; i want to trans=
mit on 7355 Hz. This frequency is a message in it selfe for amateurs ;-)<B=
R><BR>So, all in all it was a hard experiment with many difficulties and=
 the QRN situation could have been at least 15 dB better but it was an imp=
ortant test to find the tap for the L to come back on the Dreamers Band (3=
3km) with a 200m vertical. Also we have done some new record receptions an=
d can be
 very hopefully that this can be much improved in the next test, if there=
 is proper wind and less QRN that can be assumed when going to the autumn=
 :-)<BR><BR>Again thanks to all the group and hope cuagn in the next test!=
 :-)<BR><BR>Best 73, Stefan/DK7FC<BR><BR>PS: Some photos and screenshots=
 will be displayed on my QRZ.com page in some days.<BR><BR>PPS: Hopefully=
 there will come up further stations on the dreamers band within this year=
 :-)<BR><BR><BR><BR><BR><BR><BR></DIV></DIV></div></body></html>

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