Date: Sat, 29 Dec 2018 13:54:47 +0000 (UTC)
From: Markus Vester <markusvester@aol.com>
To: rsgb_lf_group@blacksheep.org
Message-ID: <1208359361.10549501.1546091687688@mail.yahoo.com>
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Subject: Re: LF: VLF Carrier on 8270.01 Hz from a ground loop antenna - The
 6th station on Paul's spectrogram
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Hi Stefan,

strangely, nothing is visible here in N=C3=BCrnberg now.

At DL0AO, the portable transmission (~ 280 km) appears to be around 9 dB st=
ronger compared to=C2=A0the institute in Heidelberg (~ 230 km,=C2=A0referen=
ce measurement=C2=A0at 7:50 UT on Dec 27). However here in N=C3=BCrnberg it=
 seems to be=C2=A0the other way round: the transmission from the institute=
=C2=A0(180 km) was=C2=A0strong=C2=A0 (up to 20 dB SNR) all day, but the sig=
nal from=C2=A0the=C2=A0guiderails (230 km) is=C2=A0completely invisible now=
.=C2=A0=20

The explanation may be that a sharp midday minimum exists at 230 km. Lookin=
g at DL0AO traces, we can see that the signal from the institute indeed alm=
ost disappeared at noon. During=C2=A0earlier Experiments=C2=A0it seemed tha=
t the minimum was very pronounced on our 180 km path, but that was later in=
 the year around April and May. This seems to make sense, as=C2=A0higher so=
lar Illumination pushed the midday ionoshere further dowen, requiring steep=
er=C2=A0skywave=C2=A0angle to arrive=C2=A0at the same 3/2 lambda path diffe=
rence for cancellation.=C2=A0

Best 73,
Markus (DF6NM)

-----Urspr=C3=BCngliche Mitteilung-----
Von: DK7FC <selberdenken@posteo.de>
An: rsgb_lf_group <rsgb_lf_group@blacksheep.org>
Verschickt: Sa, 29. Dez 2018 13:45
Betreff: LF: VLF Carrier on 8270.01 Hz from a ground loop antenna - The 6th=
 station on Paul's spectrogram

Hi VLF friends,

Since 11:35 UTC i'm running about 2.5 A antenna current into my 900m=20
long ground loop antenna. Frequency is 8270.01 Hz. The signal is very=20
strong on my own grabber in 57.6 km distance but also at DF6NM, DL0AO=20
and it looks like there is a peak now on Paul's spectrogram building up=20
slowly.
I intend to run the carrier for 2 hours or so, until the accu is almost=20
empty :-)
The H bridge PA voltage is 175 V and the power consumption is 450 W.
Today, the DC measuremant result is 66V for 1 A antenna current. It is=20
cold and wet!
More soon.

73 de DK7FC/P in JN39WI

PS: The QRN is exceptional low!!!!


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<div style=3D"font-size:10pt;font-family:arial,helvetica,sans-serif;color:b=
lack;"><div style=3D"color: black; font-family: arial,helvetica,sans-serif;=
 font-size: 10pt;">Hi Stefan,<br><br>strangely, nothing is visible here in =
N=C3=BCrnberg now.<br><br>At DL0AO, the portable transmission (~ 280 km) ap=
pears to be around 9 dB stronger compared to&nbsp;the institute in Heidelbe=
rg (~ 230 km,&nbsp;reference measurement&nbsp;at 7:50 UT on Dec 27). Howeve=
r here in N=C3=BCrnberg it seems to be&nbsp;the other way round: the transm=
ission from the institute&nbsp;(180 km) was&nbsp;strong&nbsp; (up to 20 dB =
SNR) all day, but the signal from&nbsp;the&nbsp;guiderails (230 km) is&nbsp=
;completely invisible now.&nbsp; <br><br>The explanation may be that a shar=
p midday minimum exists at 230 km. Looking at DL0AO traces, we can see that=
 the signal from the institute indeed almost disappeared at noon. During&nb=
sp;earlier Experiments&nbsp;it seemed that the minimum was very pronounced =
on our 180 km path, but that was later in the year around April and May. Th=
is seems to make sense, as&nbsp;higher solar Illumination pushed the midday=
 ionoshere further dowen, requiring steeper&nbsp;skywave&nbsp;angle to arri=
ve&nbsp;at the same 3/2 lambda path difference for cancellation.&nbsp;<br><=
br>Best 73,<br>Markus (DF6NM)<br><br>-----Urspr=C3=BCngliche Mitteilung----=
-<br>Von: DK7FC &lt;selberdenken@posteo.de&gt;<br>An: rsgb_lf_group &lt;rsg=
b_lf_group@blacksheep.org&gt;<br>Verschickt: Sa, 29. Dez 2018 13:45<br>Betr=
eff: LF: VLF Carrier on 8270.01 Hz from a ground loop antenna - The 6th sta=
tion on Paul's spectrogram<br><br></div><div dir=3D"ltr">Hi VLF friends,<br=
 clear=3D"none"><br clear=3D"none">Since 11:35 UTC i'm running about 2.5 A =
antenna current into my 900m <br clear=3D"none">long ground loop antenna. F=
requency is 8270.01 Hz. The signal is very <br clear=3D"none">strong on my =
own grabber in 57.6 km distance but also at DF6NM, DL0AO <br clear=3D"none"=
>and it looks like there is a peak now on Paul's spectrogram building up <b=
r clear=3D"none">slowly.<br clear=3D"none">I intend to run the carrier for =
2 hours or so, until the accu is almost <br clear=3D"none">empty :-)<br cle=
ar=3D"none">The H bridge PA voltage is 175 V and the power consumption is 4=
50 W.<br clear=3D"none">Today, the DC measuremant result is 66V for 1 A ant=
enna current. It is <br clear=3D"none">cold and wet!<br clear=3D"none">More=
 soon.<br clear=3D"none"><br clear=3D"none">73 de DK7FC/P in JN39WI<br clea=
r=3D"none"><br clear=3D"none">PS: The QRN is exceptional low!!!!<div class=
=3D"yqt3327850103" id=3D"yqtfd99264"><br clear=3D"none"><br clear=3D"none">=
</div></div></div>
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