Return-Path: 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 ) 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 ; 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 ; Mon, 26 Mar 2012 17:37:46 -0400 (EDT) Message-ID: <06E9A3B29AAB4B9A90E06FC866137ECB@White> From: "Markus Vester" To: 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
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.
 
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.
 
Thanks again, and = good luck to=20 all
 
73, = Markus
 

Sent: Monday, March 26, 2012 2:33 AM
Subject: VLF: OK2BVG - DF6NM QSO on 8.97 kHz

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.
 
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. 
 
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.
 
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
 
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.
 
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:
 
07:30-08:30 = "NB"     ;Lubos'=20 call: df6Nm de ok2Bvg
09:00-10:30 "BNM"  ;my reply and report: = Bvg Nm=20 M  
11:00-12:00 "RO"     ;his = confirmation and=20 report
12:30-14:00 "RTU"  ;my confirmation and thank = you
 
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.
 
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
http://df6nm.b= placed.net/VLF/ok2bvg_df6nm_120325/
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.
 
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.
 
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
http://abelian.org/vlf/fbins.shtml#p=3D1332712800&b=3D110&am= p;s=3Dsp
 
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
 
Best 73,
Markus (DF6NM)
 

From: Markus Vester
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=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).
 
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.
 
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.
 
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.
 
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. 
 
Again we find that a great deal is possible with very modest = means...
 
Best 73,
Markus (DF6NM)
 
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