Return-Path: <owner-rsgb_lf_group@blacksheep.org>
Received: from post.thorcom.com (post.thorcom.com [195.171.43.25])
by klubnl.pl (8.14.4/8.14.4/Debian-8+deb8u2) with ESMTP id x1PL4G65026228
for <rlg@klubnl.pl>; Mon, 25 Feb 2019 22:04:18 +0100
Received: from majordom by post.thorcom.com with local (Exim 4.14)
id 1gyNAy-0004i1-NO
for rs_out_1@blacksheep.org; Mon, 25 Feb 2019 20:48:37 +0000
Received: from [195.171.43.32] (helo=relay1.thorcom.net)
by post.thorcom.com with esmtp (Exim 4.14)
id 1gyN7R-0004gv-F9
for rsgb_lf_group@blacksheep.org; Mon, 25 Feb 2019 20:44:57 +0000
Received: from resqmta-ch2-09v.sys.comcast.net ([2001:558:fe21:29:69:252:207:41])
by relay1.thorcom.net with esmtps (TLSv1.2:ECDHE-RSA-AES256-GCM-SHA384:256)
(Exim 4.91)
(envelope-from <hvanesce@comcast.net>)
id 1gyN7F-0006t4-CW
for rsgb_lf_group@blacksheep.org; Mon, 25 Feb 2019 20:44:46 +0000
Received: from resomta-ch2-12v.sys.comcast.net ([69.252.207.108])
by resqmta-ch2-09v.sys.comcast.net with ESMTP
id yIC8g0uAFQNsNyN7AgJVwG; Mon, 25 Feb 2019 20:44:40 +0000
X-DKIM-Result: Domain=comcast.net Result=Signature OK
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=comcast.net;
s=q20161114; t=1551127480;
bh=/bJdA6ak2GteWld31zz1o+VKtJgGliby2r2iod5PrmI=;
h=Received:Received:From:To:Subject:Date:Message-ID:MIME-Version:
Content-Type;
b=ddl/4ZSjkbQds5jPm6w4LZRpIbT52jX3BfR8kh6kRYLE2pqO5ZIL8zZ7iQ3y/aBBk
QOzHHfiE2WVD3S3ttS4ImQ2ugH5OajTqeplVXCgiM9wqiLyVQP7cqBMKJj7jGG0YEq
9tMYsQ2bz7OxlWbQmwxYwN71fpr6TGUPUrCMAyi4ptB810eVvWct64/wxQzyN97lZN
5mlc5Do2V70jsEusbbeRSKp7ti4tAvL/99VwRT+bO0ExwIJCNDUuZGs3jUkWa5UZ3K
pF2ceaJqs3M8tsoTtDYASY5D7kNCAc2XZAaRa8ov+j9bfc9ZL7c6aeUpRwz6jQooay
jNetPc1aUpDmg==
Received: from Owner ([IPv6:2601:140:8500:7f9f:d064:ad1a:5aee:318])
by resomta-ch2-12v.sys.comcast.net with ESMTPA
id yN78gVVu5FPHiyN79gx9Jv; Mon, 25 Feb 2019 20:44:40 +0000
X-Xfinity-VMeta: sc=0;st=legit
From: <hvanesce@comcast.net>
To: <rsgb_lf_group@blacksheep.org>
References: <1341300776.3468000.1550834824126.ref@mail.yahoo.com> <1341300776.3468000.1550834824126@mail.yahoo.com> <Pine.LNX.4.64.1902220917000.23134@plato.ucs.mun.ca> <CANA3B6WfT6tDjASuhDi3c0AtjTepu4hxEGnmZ6+w7PQBt5-i9g@mail.gmail.com> <5C7415E4.7090603@posteo.de>
In-Reply-To: <5C7415E4.7090603@posteo.de>
Date: Mon, 25 Feb 2019 15:44:31 -0500
Message-ID: <009101d4cd4a$ed8530f0$c88f92d0$@comcast.net>
MIME-Version: 1.0
X-Mailer: Microsoft Outlook 14.0
Thread-Index: AQGobIVDJBpFCMgFIgT2U/vkQCRSfQJ2rAPxAlojuM0CU/BCawFWV+ikpgXbfqA=
Content-Language: en-us
X-Spam-Score: -0.7 (/)
X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net",
has NOT identified this incoming email as spam. The original
message has been attached to this so you can view it or label
similar future email. If you have any questions, see
the administrator of that system for details.
Content preview: Stefan, Congratulations on this latest milestone. 57.6 km
at 470 Hz at an SNR that would have supported 6 bits of information with 90%
of battery energy unused is impressive; nice work. Using r^2.5 extinction
it seems like another 13 dB would reach the far field.
Content analysis details: (-0.7 points, 5.0 required)
pts rule name description
---- ---------------------- --------------------------------------------------
-0.7 RCVD_IN_DNSWL_LOW RBL: Sender listed at http://www.dnswl.org/,
low trust
[2001:558:fe21:29:69:252:207:41 listed in]
[list.dnswl.org]
-0.0 SPF_PASS SPF: sender matches SPF record
0.0 FREEMAIL_FROM Sender email is commonly abused enduser mail
provider (hvanesce[at]comcast.net)
0.0 T_KAM_HTML_FONT_INVALID BODY: Test for Invalidly Named or
Formatted Colors in HTML
0.0 HTML_MESSAGE BODY: HTML included in message
X-Scan-Signature: 6ae4eec5875a1b41a36d2a35c03bf59e
Subject: LF: RE: 470.1 Hz detected in 57.6 km distance
Content-Type: multipart/alternative;
boundary="----=_NextPart_000_0092_01D4CD21.04B199F0"
X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com
X-Spam-Level: *
X-Spam-Status: No, hits=1.1 required=5.0 tests=HTML_30_40,HTML_MESSAGE,
NO_REAL_NAME autolearn=no version=2.63
X-SA-Exim-Scanned: Yes
Sender: owner-rsgb_lf_group@blacksheep.org
Precedence: bulk
Reply-To: rsgb_lf_group@blacksheep.org
X-Listname: rsgb_lf_group
X-SA-Exim-Rcpt-To: rs_out_1@blacksheep.org
X-SA-Exim-Scanned: No; SAEximRunCond expanded to false
This is a multipart message in MIME format.
------=_NextPart_000_0092_01D4CD21.04B199F0
Content-Type: text/plain;
charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
Stefan,
=20
Congratulations on this latest milestone. 57.6 km at 470 Hz at an SNR =
that would have supported 6 bits of information with 90% of battery =
energy unused is impressive; nice work.
=20
Using r^2.5 extinction it seems like another 13 dB would reach the far =
field.
=20
I wonder if some fine-tuning of distance could be helpful in that case. =
I=E2=80=99m not sure how to easily calculate modal null separation =
distances at wavelengths greater than ionospheric height, but by =
extrapolation from 3 kHz it would seem that at 470 Hz, ten nulls (from =
modes 1 through 5) might be fairly closely spaced near a 110 km target =
location, such that a small increase or decrease in receiver distance =
from transmitter could move the receiver toward a peak in the =
interference pattern.
=20
I=E2=80=99m not sure how you changed receiver locations in the past so =
perhaps in this case you can=E2=80=99t easily move the receiver.
=20
Your 2-hour spectral plot is a welcome sight.
=20
73,
=20
Jim AA5BW
=20
=20
=20
From: owner-rsgb_lf_group@blacksheep.org =
[mailto:owner-rsgb_lf_group@blacksheep.org] On Behalf Of DK7FC
Sent: Monday, February 25, 2019 11:21 AM
To: rsgb_lf_group@blacksheep.org
Subject: ULF: 470.1 Hz detected in 57.6 km distance
=20
Hi ULF friends,=20
Last Friday i run another carrier transmission on my 900m long ground =
loop antenna. It was the second experiment at 470.1 Hz. The last =
experiment failed because just a few 1/10 dB were missed to reach the 14 =
dB SNR level which is the criterium for a valid detection.
During the last week i managed to reduce the background QRM on the E =
field significantly (at least 10 dB) in that frequency range by changing =
the ground connection on the RX system, so it was an EMC issue.
In the recent experiment the DC measurement showed 1 A at 58 V, so the =
loop loss was just 58 Ohm, which is one of the best values so far.
Conecting the PA to the LiFePo4 accu produced 620 W RF power and 3 A =
antenna current (!) in the first moment. But the DC/DC converter became =
a bit to warm and i (thought) had enough time so i reduced the input =
voltage. The power dropped to 460 W and so the antenna current during =
the experiment was 2.75 A. The carrier started at 14:50 UTC and was on =
the air for 2.5 hours!
It was a quiet day and so i decided spontaneously to do the experiment. =
But i've been at work in the morning and so i was late, a bit to late =
actually, since the band already opened and the QRN increased during the =
experiment. Who knows what happened to the phase over that path. The =
only RX station detecting the signal was my own tree in 57.6 km =
distance. Due to the rising QRN the last 30 minutes did not help to =
rise the SNR of the postprocessed spectrum peak. But 2 hours were fine =
to get a clear copy!
Usually i have to ways to determine the final SNR: One is to read the =
output of the EbNaut decoder decoding a '*' message. The ouput, if using =
the -f15 -f16 -M'*****' options, then shows the carrier S/N directly.
The other method is a script that calculates the SNR dB value based on =
the spectrum peak and 0 dB noise level. This 0 dB noise level =
calculation is done according to the description in SpectumLab's help =
sites. Here is the quote:
"The definition of noise levels is not easy. Here is the basic algorithm =
of the 'noise' function:=20
1. An array of amplitudes (usually dB values) from the last FFT =
calculation is sorted into order of increasing amplitude.=20
2. The amplitude of the lower quartile value (for example bin number 256 =
in a sorted set of 1024 points) PLUS 3dB is then returned as an estimate =
of the mean noise level.=20
This technique automatically throws away very high values (strong =
signals) that would otherwise affect the result."
This technique is used in my script. I find the result adequate, the 0 =
dB level is visually in the center of the noise. But sometimes the SNR =
statements are a bit different between my script and the result of the =
EbNaut program. Maybe it is due to the fact that i am calculating the =
mean level based on just 1000 bins arround the spectrum peak, and EbNaut =
watches a higher bandwidth, which may contain more QRM peaks that rise =
the mean noise baseline?
That may explain why my script whows an SNR of 18.2 dB whereas the =
EbNaut decoder says it is an SNR of 16.17 dB. Anyway, well above 14 dB.
The signal was strong enough, it could have carried a 6 character EbNaut =
message.
Attached is a 424 uHz spectrogram showing a short carrier trace just =
before the high QRN sets in. Also attached, a single spectrum peak =
detection and the result for an EbNaut message (showing the carrier =
S/N).
So, it is the first amateur radio signal on the 638 km band detected =
over such a distance i think.
73, Stefan
------=_NextPart_000_0092_01D4CD21.04B199F0
Content-Type: text/html;
charset="UTF-8"
Content-Transfer-Encoding: quoted-printable
<html xmlns:v=3D"urn:schemas-microsoft-com:vml" =
xmlns:o=3D"urn:schemas-microsoft-com:office:office" =
xmlns:w=3D"urn:schemas-microsoft-com:office:word" =
xmlns:m=3D"http://schemas.microsoft.com/office/2004/12/omml" =
xmlns=3D"http://www.w3.org/TR/REC-html40"><head><meta =
http-equiv=3DContent-Type content=3D"text/html; charset=3Dutf-8"><meta =
name=3DGenerator content=3D"Microsoft Word 14 (filtered =
medium)"><style><!--
/* Font Definitions */
@font-face
{font-family:Calibri;
panose-1:2 15 5 2 2 2 4 3 2 4;}
@font-face
{font-family:Tahoma;
panose-1:2 11 6 4 3 5 4 4 2 4;}
/* Style Definitions */
p.MsoNormal, li.MsoNormal, div.MsoNormal
{margin:0in;
margin-bottom:.0001pt;
font-size:12.0pt;
font-family:"Times New Roman","serif";
color:black;}
a:link, span.MsoHyperlink
{mso-style-priority:99;
color:blue;
text-decoration:underline;}
a:visited, span.MsoHyperlinkFollowed
{mso-style-priority:99;
color:purple;
text-decoration:underline;}
p
{mso-style-priority:99;
mso-margin-top-alt:auto;
margin-right:0in;
mso-margin-bottom-alt:auto;
margin-left:0in;
font-size:12.0pt;
font-family:"Times New Roman","serif";
color:black;}
span.EmailStyle18
{mso-style-type:personal-reply;
font-family:"Calibri","sans-serif";
color:#1F497D;}
.MsoChpDefault
{mso-style-type:export-only;
font-size:10.0pt;}
@page WordSection1
{size:8.5in 11.0in;
margin:1.0in 1.0in 1.0in 1.0in;}
div.WordSection1
{page:WordSection1;}
/* List Definitions */
@list l0
{mso-list-id:411318582;
mso-list-template-ids:-57382278;}
ol
{margin-bottom:0in;}
ul
{margin-bottom:0in;}
--></style><!--[if gte mso 9]><xml>
<o:shapedefaults v:ext=3D"edit" spidmax=3D"1026" />
</xml><![endif]--><!--[if gte mso 9]><xml>
<o:shapelayout v:ext=3D"edit">
<o:idmap v:ext=3D"edit" data=3D"1" />
</o:shapelayout></xml><![endif]--></head><body bgcolor=3Dwhite =
lang=3DEN-US link=3Dblue vlink=3Dpurple><div class=3DWordSection1><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>Stefan,<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>Congratulations on this latest milestone. 57.6 km at 470 Hz at an SNR =
that would have supported 6 bits of information with 90% of battery =
energy unused is impressive; nice work.<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>Using r^2.5 extinction it seems like another 13 dB would reach the =
far field.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>I wonder if some fine-tuning of distance could be helpful in that =
case. I=E2=80=99m not sure how to easily calculate modal null separation =
distances at wavelengths greater than ionospheric height, but by =
extrapolation from 3 kHz it would seem that at 470 Hz, ten nulls (from =
modes 1 through 5) might be fairly closely spaced near a 110 km target =
location, such that a small increase or decrease in receiver distance =
from transmitter could move the receiver toward a peak in the =
interference pattern.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>I=E2=80=99m not sure how you changed receiver locations in the past =
so perhaps in this case you can=E2=80=99t easily move the =
receiver.<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>Your 2-hour spectral plot is a welcome sight.<o:p></o:p></span></p><p =
class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>73,<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'>Jim AA5BW<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'> =C2=A0<o:p></o:p></span></p><p class=3DMsoNormal><span =
style=3D'font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497=
D'><o:p> </o:p></span></p><div><div =
style=3D'border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0in =
0in 0in'><p class=3DMsoNormal><b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowt=
ext'>From:</span></b><span =
style=3D'font-size:10.0pt;font-family:"Tahoma","sans-serif";color:windowt=
ext'> owner-rsgb_lf_group@blacksheep.org =
[mailto:owner-rsgb_lf_group@blacksheep.org] <b>On Behalf Of =
</b>DK7FC<br><b>Sent:</b> Monday, February 25, 2019 11:21 =
AM<br><b>To:</b> rsgb_lf_group@blacksheep.org<br><b>Subject:</b> ULF: =
470.1 Hz detected in 57.6 km =
distance<o:p></o:p></span></p></div></div><p =
class=3DMsoNormal><o:p> </o:p></p><p class=3DMsoNormal>Hi ULF =
friends, <br><br>Last Friday i run another carrier transmission on my =
900m long ground loop antenna. It was the second experiment at <b>470.1 =
Hz</b>. The last experiment failed because just a few 1/10 dB were =
missed to reach the 14 dB SNR level which is the criterium for a valid =
detection.<br>During the last week i managed to reduce the background =
QRM on the E field significantly (at least 10 dB) in that frequency =
range by changing the ground connection on the RX system, so it was an =
EMC issue.<br><br>In the recent experiment the DC measurement showed 1 A =
at 58 V, so the loop loss was just 58 Ohm, which is one of the best =
values so far.<br><br>Conecting the PA to the LiFePo4 accu produced 620 =
W RF power and 3 A antenna current (!) in the first moment. But the =
DC/DC converter became a bit to warm and i (thought) had enough time so =
i reduced the input voltage. The power dropped to <b>460 W</b> and so =
the <b>antenna current during the experiment was 2.75 A</b>. The carrier =
started at 14:50 UTC and was on the air for 2.5 hours!<br><br>It was a =
quiet day and so i decided spontaneously to do the experiment. But i've =
been at work in the morning and so i was late, a bit to late actually, =
since the band already opened and the QRN increased during the =
experiment. Who knows what happened to the phase over that path. The =
only RX station detecting the signal was my own tree in <b>57.6 km =
distance</b>. Due to the rising QRN the last 30 minutes did not =
help to rise the SNR of the postprocessed spectrum peak. But 2 hours =
were fine to get a clear copy!<br><br>Usually i have to ways to =
determine the final SNR: One is to read the output of the EbNaut decoder =
decoding a '*' message. The ouput, if using the -f15 -f16 -M'*****' =
options, then shows the carrier S/N directly.<br>The other method is a =
script that calculates the SNR dB value based on the spectrum peak and 0 =
dB noise level. This 0 dB noise level calculation is done according to =
the description in SpectumLab's help sites. Here is the =
quote:<br>"<b>The definition of noise levels is not easy. Here is =
the basic algorithm of the 'noise' function: </b><o:p></o:p></p><ol =
start=3D1 type=3D1><li class=3DMsoNormal =
style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 =
level1 lfo1'><b>An array of amplitudes (usually dB values) from the last =
FFT calculation is sorted into order of increasing amplitude. =
</b><o:p></o:p></li><li class=3DMsoNormal =
style=3D'mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;mso-list:l0 =
level1 lfo1'><b>The amplitude of the lower quartile value (for example =
bin number 256 in a sorted set of 1024 points) PLUS 3dB is then returned =
as an estimate of the mean noise level. =
</b><o:p></o:p></li></ol><p><b>This technique automatically throws away =
very high values (strong signals) that would otherwise affect the =
result.</b>"<o:p></o:p></p><p class=3DMsoNormal>This technique is =
used in my script. I find the result adequate, the 0 dB level is =
visually in the center of the noise. But sometimes the SNR statements =
are a bit different between my script and the result of the EbNaut =
program. Maybe it is due to the fact that i am calculating the mean =
level based on just 1000 bins arround the spectrum peak, and EbNaut =
watches a higher bandwidth, which may contain more QRM peaks that rise =
the mean noise baseline?<br>That may explain why my script whows an<b> =
SNR of 18.2 dB</b> whereas the EbNaut decoder says it is an <b>SNR of =
16.17 dB</b>. Anyway, well above 14 dB.<br><br>The signal was strong =
enough, it could have carried a <b>6 character EbNaut =
message</b>.<br><br>Attached is a 424 uHz spectrogram showing a short =
carrier trace just before the high QRN sets in. Also attached, a single =
spectrum peak detection and the result for an EbNaut message (showing =
the carrier S/N).<br><br><br>So, it is the first amateur radio signal on =
the <b>638 km band</b> detected over such a distance i =
think.<br><br><br>73, Stefan<o:p></o:p></p></div></body></html>
------=_NextPart_000_0092_01D4CD21.04B199F0--