Return-Path: <owner-rsgb_lf_group@blacksheep.org>
Received: from post.thorcom.com (post.thorcom.com [195.171.43.25])
by mtain-md05.r1000.mx.aol.com (Internet Inbound) with ESMTP id B151B380000E5;
Mon, 26 Mar 2012 17:39:11 -0400 (EDT)
Received: from majordom by post.thorcom.com with local (Exim 4.14)
id 1SCHc4-00020e-QT
for rs_out_1@blacksheep.org; Mon, 26 Mar 2012 22:38:04 +0100
Received: from [195.171.43.32] (helo=relay1.thorcom.net)
by post.thorcom.com with esmtp (Exim 4.14)
id 1SCHc4-00020V-0X
for rsgb_lf_group@blacksheep.org; Mon, 26 Mar 2012 22:38:04 +0100
Received: from imr-da04.mx.aol.com ([205.188.105.146])
by relay1.thorcom.net with esmtp (Exim 4.63)
(envelope-from <markusvester@aol.com>)
id 1SCHc0-0003IB-7L
for rsgb_lf_group@blacksheep.org; Mon, 26 Mar 2012 22:38:03 +0100
Received: from mtaout-db01.r1000.mx.aol.com (mtaout-db01.r1000.mx.aol.com [172.29.51.193])
by imr-da04.mx.aol.com (8.14.1/8.14.1) with ESMTP id q2QLblNr024501
for <rsgb_lf_group@blacksheep.org>; Mon, 26 Mar 2012 17:37:47 -0400
Received: from White (nrbg-4d074f10.pool.mediaWays.net [77.7.79.16])
by mtaout-db01.r1000.mx.aol.com (MUA/Third Party Client Interface) with ESMTPA id 630F4E0000A2
for <rsgb_lf_group@blacksheep.org>; Mon, 26 Mar 2012 17:37:46 -0400 (EDT)
Message-ID: <06E9A3B29AAB4B9A90E06FC866137ECB@White>
From: "Markus Vester" <markusvester@aol.com>
To: <rsgb_lf_group@blacksheep.org>
References: <8CED1D568912879-1568-4B17@angweb-usd004.sysops.aol.com> <5BBB1EB8BEC445D6A33CE2E0CF6D7620@White>
Date: Mon, 26 Mar 2012 23:37:44 +0200
MIME-Version: 1.0
X-Priority: 3
X-MSMail-Priority: Normal
Importance: Normal
X-Mailer: Microsoft Windows Live Mail 12.0.1606
X-MimeOLE: Produced By Microsoft MimeOLE V12.0.1606
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=mx.aol.com;
s=20110426; t=1332797867;
bh=OBsv5Vuz1ppLnIVpTqj4JAhlvrewbkh5X3Zi9a58MlU=;
h=From:To:Subject:Message-ID:Date:MIME-Version:Content-Type;
b=OHSHSaUDqeKWy0fqekT5TErotuD8PHAqi3Plrk3QBZRsuHkZxKxIkLh2hg+EPWc1V
g+/tXXo7nChVkJVVTXdasMrMDGDVlcBSlBlAtwGnBKfKra9SiLL9ItnVCITdZmmFx0
1ebw+/TcPYksqKxOg0eog40fO5k6rlTBfTv2k87Q=
X-AOL-SCOLL-SCORE: 0:2:434873056:93952408
X-AOL-SCOLL-URL_COUNT: 0
X-Spam-Score: 0.0 (/)
X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001
Subject: Re: VLF: OK2BVG - DF6NM QSO on 8.97 kHz
Content-Type: multipart/alternative;
boundary="----=_NextPart_000_0030_01CD0BA9.71C273C0"
X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com
X-Spam-Level:
X-Spam-Status: No, hits=0.7 required=5.0 tests=HTML_20_30,
HTML_FONTCOLOR_UNKNOWN,HTML_MESSAGE,MISSING_OUTLOOK_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
x-aol-global-disposition: G
X-AOL-SCOLL-SCORE: 0:2:457481056:93952408
X-AOL-SCOLL-URL_COUNT: 0
X-AOL-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-d021.1 ; domain : mx.aol.com DKIM : pass
x-aol-sid: 3039ac1d60594f70e1ff0f28
X-AOL-IP: 195.171.43.25
X-AOL-SPF: domain : blacksheep.org SPF : none
Dies ist eine mehrteilige Nachricht im MIME-Format.
------=_NextPart_000_0030_01CD0BA9.71C273C0
Content-Type: text/plain;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
Many thanks to all who sent kind comments regarding the recent Dreamer's =
band QSO, either direct or via the LF reflector. You can surely imagine =
our joy when the final "R" crept out of the noise, completing the QSO =
;-) In the meantime, Lubos sent a set of screenshots showing the =
spectral peak of each symbol - I have uploaded them to the bplaced =
directory as well.
Please note that the micro-QSO with DJ2LF (first in the VLF far-field) =
actually happened on June 4, 2010, and not in 2009 as I erroneously =
stated.
Thanks again, and good luck to all
73, Markus
From: Markus Vester=20
Sent: Monday, March 26, 2012 2:33 AM
To: rsgb_lf_group@blacksheep.org=20
Subject: VLF: OK2BVG - DF6NM QSO on 8.97 kHz
Today between 7:30 and 14:00, Lubos OK2BVG and I successfully completed =
a two-way contact on 8.97 kHz. We believe that this is the first =
international QSO ever on VLF.=20
The distance between Breclav (JN88KS) and Nuernberg (JN59NJ 69es) is =
approximately 424 km. The weekend before, Lubos and I had found that we =
could see each other's VLF transmissions from our small home antennas in =
a slow spectrogram, using about 0.45 millihertz FFT resolution =
("DFCW-6000"). This long integration requires about 2000 seconds of =
continuous non-interrupted carrier to reach full sensitivity. =20
We decided to use absolute frequency encoding of characters ("MFSK-37" =
mode), which has a simple structure but is significantly more efficient =
than two-frequency DFCW. The software signal generators in SpecLab were =
used to create 30 minute dashes by editing the frequency in 1 mHz steps =
every half hour. This can be automated by opening a textfile which is =
read by the "periodic actions" function. Between transmissions, =
additional half-hour gaps were inserted to let the FFT ring down, and =
allow for TX-RX reconnections.
Characters are identified by reading the frequencies above 8970.000 Hz, =
with 8970.000 to .009 assigned to the numbers, .010 idle or space, and =
.011 to .036 the letters A-Z. Lubos used a Rubidium standard to lock his =
transmit samplerate, while both receivers and my TX were synchronized by =
military MSK signals from GQD (22.1 kHz) and DHO (23.4 kHz).=20
With about 80 watts from an audio amplifier, I could get up to 0.38 A =
antenna current into my top-loaded vertical 9 m above the roof, =
radiating on the order of 10 to 15 microwatts. I believe that Lubos is =
using similar equipment, perhaps a couple of dB stronger. For receive, =
my soundcard was connected straight to the loading coil and antenna, =
whereas Lubos has an active probe at a quiet site remote from his TX =
location.
We wanted to go for a "full QSO" format with reports and confirmations, =
beyond the rudimentary three-dash "micro-QSO" format which was used in =
June 2009 between DJ2LF and myself. With single-letter suffixes, we =
ended up proceeding as follows:
07:30-08:30 "NB" ;Lubos' call: df6Nm de ok2Bvg
09:00-10:30 "BNM" ;my reply and report: Bvg Nm M =20
11:00-12:00 "RO" ;his confirmation and report
12:30-14:00 "RTU" ;my confirmation and thank you
Although today the noise was not as low as it had been before, we =
managed to exchange the essential information in 5.5 hours until 13 UT, =
after which QRN from lightning in southeast Europe became strong enough =
to obliterate further copy.
Attached image contains captures from Lubos' grabber at Apollons temple =
(top) and my receiver (bottom), with screenshots from the DK7FC and =
OE3GHB grabbers pasted inbetween. The original captures are at
http://df6nm.bplaced.net/VLF/ok2bvg_df6nm_120325/
All spectrograms were stretched to the same timescale (5 min/pixel). On =
the left hand side, you can see a MFSK pre-test from Lubos, sending his =
call to his own grabber at very low power. There was also a long dash =
from OE3GHB on 8970.030, and a carrier from DJ8WX on 8970.022 is visible =
at DK7FC.
The rightmost part of the captures shows the essential eight dashes from =
our QSO. You can see that I had almost lost Lubos' "B" when my noise =
blanker triggered heavily on local QRM, inducing me to give an "M" =
rather than "O" report. But hovering the cursor to 8:15 UT does show the =
peak at 8970.012 Hz in the spectrum graph. My final "R" is just barely =
visible at .028, whereas the following "TU" at .030 and .031 ended up =
drowning in the increasing noise.
During the lowest noise period (9 - 12 UT), the dashes were visible =
(though not decodable) in 4.5 mHz "600" spectrograms. At that time, our =
symbols also appeared on Paul Nicholson's spectrogram
http://abelian.org/vlf/fbins.shtml#p=3D1332712800&b=3D110&s=3Dsp
Thanks again to Lubos for the effort and patience! Although exchanging =
half-hour symbols is tedious and may sound boring to some, both of us =
enjoyed it and actually found it quite exciting.=20
Best 73,
Markus (DF6NM)
From: Markus Vester=20
Sent: Friday, March 16, 2012 11:46 PM
To: rsgb_lf_group@blacksheep.org=20
Subject: VLF: MFSK-37 tests above 8970 today
To explore the possibility of further two-way VLF contacts from my home =
antenna, I have conducted a test in MFSK-37 mode this morning. I was =
hoping to reach 0.42 mHz ("6000") grabbers using UT-synchronized =
half-hour dashes. Similar to an earlier kite experiment, I used absolute =
frequency encoding of characters in 1 mHz steps (0 =3D 8970.000, 1 =3D =
8970.001, ... 9 =3D 8970.009, idle =3D 8970.010, A =3D 8970.011, .. Z =
=3D 8970.036 Hz).
The plan was to transmit my complete callsign in 2.5 hours between 8:00 =
and 10:30. Unfortunately DHO locking failed during the first two =
characters, which came out some 9 mHz low. Attached image shows what was =
actually sent according to my "monitor", which is a high harmonic of the =
transmitted VLF signal accidentally aliased into the LF TA window.
I was pleased to find all the dashes showing up clearly as bright dots =
on the OK2BVG "6000" grabber, and even left visible traces in his "600" =
window. As I had also received Lubos' transmission last weekend with a =
good margin in 0.48 mHz, a two-way QSO between us would probably be =
feasible within a few hours.
Paul Nicholson's 0.278 mHz super-sensitive spectrogram also shows the =
transmission at 120 degrees azimuth, even though the dashes were really =
too short to reach full SNR in this bandwidth.
Results on the DK7C grabber were not quite as good, with only a single =
clear dot on .006 Hz. This may partly have been due to the previously =
experienced daytime minimum at our distance (180 km). Nothing distictive =
was visible at OE3GHB, who is at similar distance as OK2BVG, but seems =
to have suffered from a bit of local QRM at the time.=20
Again we find that a great deal is possible with very modest means...
Best 73,
Markus (DF6NM)
------=_NextPart_000_0030_01CD0BA9.71C273C0
Content-Type: text/html;
charset="iso-8859-1"
Content-Transfer-Encoding: quoted-printable
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD>
<META http-equiv=3DContent-Type =
content=3Dtext/html;charset=3Diso-8859-1>
<META content=3D"MSHTML 6.00.6000.17108" name=3DGENERATOR></HEAD>
<BODY id=3DMailContainerBody=20
style=3D"PADDING-RIGHT: 10px; PADDING-LEFT: 10px; PADDING-TOP: 15px"=20
bgColor=3D#ffffff leftMargin=3D0 topMargin=3D0 CanvasTabStop=3D"true"=20
name=3D"Compose message area">
<DIV><FONT face=3DArial size=3D2>Many thanks to all who sent kind =
comments regarding=20
the recent Dreamer's band QSO, either direct or via the LF =
reflector.=20
You can surely imagine our joy when the final "R" crept =
out of=20
the noise, completing the QSO ;-) In the meantime, Lubos =
sent a set=20
of screenshots showing the spectral peak of each symbol - =
I have=20
uploaded them to the bplaced directory as well.</FONT></DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial></FONT> </DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial>Please =
note that the=20
micro-QSO with DJ2LF (first in the VLF =
far-field) actually happened on=20
June 4, 2010, and not in 2009 as I erroneously stated.</FONT></DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial></FONT> </DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial>Thanks again, and =
good luck to=20
all</FONT></DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial></FONT> </DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial>73, =
Markus</FONT></DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial></FONT> </DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial></FONT><FONT=20
face=3DArial></FONT><FONT face=3DArial></FONT><FONT =
face=3DArial></FONT><FONT=20
face=3DArial></FONT><FONT face=3DArial></FONT><FONT =
face=3DArial></FONT><FONT=20
face=3DArial></FONT><FONT face=3DArial></FONT><FONT =
face=3DArial></FONT><FONT=20
face=3DArial></FONT><FONT face=3DArial></FONT><FONT =
face=3DArial></FONT><BR></DIV>
<DIV style=3D"BACKGROUND: #f5f5f5; FONT: 10pt Tahoma">
<DIV style=3D"font-color: black"><B>From:</B> <A =
title=3Dmarkusvester@aol.com=20
href=3D"mailto:markusvester@aol.com">Markus Vester</A> </DIV>
<DIV><B>Sent:</B> Monday, March 26, 2012 2:33 AM</DIV>
<DIV><B>To:</B> <A title=3Drsgb_lf_group@blacksheep.org=20
href=3D"mailto:rsgb_lf_group@blacksheep.org">rsgb_lf_group@blacksheep.org=
</A>=20
</DIV>
<DIV><B>Subject:</B> VLF: OK2BVG - DF6NM QSO on 8.97 kHz</DIV></DIV>
<DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT><FONT=20
face=3DArial size=3D2></FONT><FONT face=3DArial size=3D2></FONT><FONT =
face=3DArial=20
size=3D2></FONT><FONT face=3DArial size=3D2></FONT><FONT face=3DArial=20
size=3D2></FONT><FONT face=3DArial size=3D2></FONT><FONT face=3DArial=20
size=3D2></FONT><FONT face=3DArial size=3D2></FONT><FONT face=3DArial=20
size=3D2></FONT><BR></DIV>
<DIV><FONT face=3DArial size=3D2>Today between 7:30 and 14:00, =
Lubos OK2BVG and=20
I successfully completed a two-way contact on 8.97 kHz. We believe that =
this is=20
the first international QSO ever on VLF. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The distance between Breclav (JN88KS) =
and Nuernberg=20
(JN59NJ 69es) is approximately 424 km. The weekend before, Lubos and I =
had found=20
that we could see each other's VLF transmissions from our small home =
antennas in=20
a slow spectrogram, using about 0.45 millihertz FFT resolution =
("DFCW-6000").=20
This long integration requires about 2000 seconds of continuous =
non-interrupted=20
carrier to reach full sensitivity. </FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>We decided to use absolute frequency =
encoding of=20
characters ("MFSK-37" mode), which has a simple structure but is =
significantly=20
more efficient than two-frequency DFCW. The software signal generators =
in=20
SpecLab were used to create 30 minute dashes by editing the frequency in =
1 mHz=20
steps every half hour. This can be automated by opening a textfile which =
is read by the "periodic actions" function. Between transmissions,=20
additional half-hour gaps were inserted to let the FFT ring down, and =
allow for=20
TX-RX reconnections.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Characters are identified by reading =
the=20
frequencies above 8970.000 Hz, with 8970.000 to .009 assigned to the =
numbers,=20
.010 idle or space, and .011 to .036 the letters A-Z. Lubos used a =
Rubidium=20
standard to lock his transmit samplerate, while both receivers and my TX =
were=20
synchronized by military MSK signals from GQD (22.1 kHz) and DHO (23.4 =
kHz).=20
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>With about 80 watts from an audio =
amplifier, I=20
could get up to 0.38 A antenna current into my top-loaded vertical 9 m =
above the=20
roof, radiating on the order of 10 to 15 microwatts. I believe that =
Lubos is=20
using similar equipment, perhaps a couple of dB stronger. For =
receive, my=20
soundcard was connected straight to the loading coil and antenna, =
whereas Lubos=20
has an active probe at a quiet site remote from his TX=20
location.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>We wanted to go for a "full QSO" format =
with=20
reports and confirmations, beyond the rudimentary three-dash "micro-QSO" =
format=20
which was used in June 2009 between DJ2LF and myself. With single-letter =
suffixes, we ended up proceeding as follows:</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>07:30-08:30 =
"NB" ;Lubos'=20
call: df6Nm de ok2Bvg<BR>09:00-10:30 "BNM" ;my reply and report: =
Bvg Nm=20
M <BR>11:00-12:00 "RO" ;his =
confirmation and=20
report<BR>12:30-14:00 "RTU" ;my confirmation and thank =
you</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Although today the noise was not as low =
as it had=20
been before, we managed to exchange the essential information in 5.5 =
hours until=20
13 UT, after which QRN from lightning in southeast Europe became strong =
enough=20
to obliterate further copy.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Attached image contains captures from =
Lubos'=20
grabber at Apollons temple (top) and my receiver (bottom), with =
screenshots from=20
the DK7FC and OE3GHB grabbers pasted inbetween. The original captures =
are=20
at<BR><A=20
title=3D"http://df6nm.bplaced.net/VLF/ok2bvg_df6nm_120325/ STRG + =
Klicken, um Verkn=FCpfung zu folgen"=20
href=3D"http://df6nm.bplaced.net/VLF/ok2bvg_df6nm_120325/">http://df6nm.b=
placed.net/VLF/ok2bvg_df6nm_120325/</A><BR>All=20
spectrograms were stretched to the same timescale (5 min/pixel). On the =
left=20
hand side, you can see a MFSK pre-test from Lubos, sending his call to =
his own=20
grabber at very low power. There was also a long dash from OE3GHB on =
8970.030,=20
and a carrier from DJ8WX on 8970.022 is visible at DK7FC.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>The rightmost part of the captures =
shows the=20
essential eight dashes from our QSO. You can see that I had almost =
lost =20
Lubos' "B" when my noise blanker triggered heavily on local QRM, =
inducing me to=20
give an "M" rather than "O" report. But hovering the cursor to 8:15 UT =
does show=20
the peak at 8970.012 Hz in the spectrum graph. My final "R" is just =
barely=20
visible at .028, whereas the following "TU" at .030 and .031 ended up =
drowning=20
in the increasing noise.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>During the lowest noise period (9 - 12 =
UT), the=20
dashes were visible (though not decodable) in 4.5 mHz "600" =
spectrograms. At=20
that time, our symbols also appeared on Paul Nicholson's =
spectrogram<BR><A=20
title=3D"http://abelian.org/vlf/fbins.shtml#p=3D1332712800&b=3D110&am=
p;s=3Dsp STRG + Klicken, um Verkn=FCpfung zu folgen"=20
href=3D"http://abelian.org/vlf/fbins.shtml#p=3D1332712800&b=3D110&=
;s=3Dsp">http://abelian.org/vlf/fbins.shtml#p=3D1332712800&b=3D110&am=
p;s=3Dsp</A></FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Thanks again to Lubos for the effort =
and=20
patience! Although exchanging half-hour symbols is tedious and may =
sound=20
boring to some, both of us enjoyed it and actually found it quite =
exciting.=20
</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT> </DIV>
<DIV><FONT face=3DArial size=3D2>Best 73,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Markus (DF6NM)</FONT></DIV>
<DIV style=3D"FONT: 10pt Tahoma"><FONT face=3DArial></FONT><FONT=20
face=3DArial></FONT><FONT face=3DArial></FONT><FONT =
face=3DArial></FONT><FONT=20
face=3DArial></FONT><FONT face=3DArial></FONT><FONT =
face=3DArial></FONT><FONT=20
face=3DArial></FONT><FONT face=3DArial></FONT><FONT =
face=3DArial></FONT><FONT=20
face=3DArial></FONT><FONT face=3DArial></FONT><FONT =
face=3DArial></FONT> </DIV>
<DIV style=3D"FONT: 10pt Tahoma">
<DIV><FONT face=3DArial></FONT><BR></DIV>
<DIV style=3D"BACKGROUND: #f5f5f5">
<DIV style=3D"font-color: black"><B>From:</B> <A=20
title=3D"mailto:markusvester@aol.com STRG + Klicken, um =
Verkn=FCpfung zu folgen"=20
href=3D"mailto:markusvester@aol.com">Markus Vester</A> </DIV>
<DIV><B>Sent:</B> Friday, March 16, 2012 11:46 PM</DIV>
<DIV><B>To:</B> <A=20
title=3D"mailto:rsgb_lf_group@blacksheep.org STRG + Klicken, um =
Verkn=FCpfung zu folgen"=20
href=3D"mailto:rsgb_lf_group@blacksheep.org">rsgb_lf_group@blacksheep.org=
</A>=20
</DIV>
<DIV><B>Subject:</B> VLF: MFSK-37 tests above 8970 =
today</DIV></DIV></DIV>
<DIV><FONT face=3DArial size=3D2></FONT><FONT face=3DArial =
size=3D2></FONT><FONT=20
face=3DArial size=3D2></FONT><FONT face=3DArial size=3D2></FONT><FONT =
face=3DArial=20
size=3D2></FONT><FONT face=3DArial size=3D2></FONT><FONT face=3DArial=20
size=3D2></FONT><FONT face=3DArial size=3D2></FONT><BR></DIV><FONT =
face=3Darial=20
color=3Dblack size=3D2>
<DIV>To explore the possibility of further two-way VLF contacts =
from my=20
home antenna, I have conducted a test in MFSK-37 mode this morning. I =
was hoping=20
to reach 0.42 mHz ("6000") grabbers using UT-synchronized half-hour =
dashes.=20
Similar to an earlier kite experiment, I used absolute frequency=20
encoding of characters in 1 mHz steps (0 =3D 8970.000, 1 =3D =
8970.001, ... 9 =3D=20
8970.009, idle =3D 8970.010, A =3D 8970.011, .. Z =3D 8970.036 =
Hz).</DIV>
<DIV> </DIV>
<DIV>The plan was to transmit my complete callsign in 2.5 hours between =
8:00 and=20
10:30. Unfortunately DHO locking failed during the first two =
characters,=20
which came out some 9 mHz low. Attached image shows what was =
actually=20
sent according to my "monitor", which is a high harmonic of the =
transmitted=20
VLF signal accidentally aliased into the LF TA window.</DIV>
<DIV> </DIV>
<DIV>I was pleased to find all the dashes showing up clearly =
as bright=20
dots on the OK2BVG "6000" grabber, and even left visible =
traces in his=20
"600" window. As I had also received Lubos' transmission last =
weekend=20
with a good margin in 0.48 mHz, a two-way QSO between us would probably =
be=20
feasible within a few hours.</DIV>
<DIV> </DIV>
<DIV>Paul Nicholson's 0.278 mHz super-sensitive spectrogram also =
shows the=20
transmission at 120 degrees azimuth, even though the dashes were really =
too=20
short to reach full SNR in this bandwidth.</DIV>
<DIV> </DIV>
<DIV>Results on the DK7C grabber were not quite as good, with only a =
single=20
clear dot on .006 Hz. This may partly have been due to the =
previously=20
experienced daytime minimum at our distance (180 km). Nothing =
distictive=20
was visible at OE3GHB, who is at similar distance as OK2BVG, but =
seems to=20
have suffered from a bit of local QRM at the time. </DIV>
<DIV> </DIV>
<DIV>Again we find that a great deal is possible with very modest =
means...</DIV>
<DIV> </DIV>
<DIV>Best 73,</DIV>
<DIV>Markus (DF6NM)</DIV>
<DIV> </DIV></FONT></BODY></HTML>
------=_NextPart_000_0030_01CD0BA9.71C273C0--