Return-Path: Received: from mtain-dd03.r1000.mx.aol.com (mtain-dd03.r1000.mx.aol.com [172.29.64.143]) by air-mb01.mail.aol.com (v129.4) with ESMTP id MAILINMB013-a1874c0a6ab610f; Sat, 05 Jun 2010 11:18:14 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dd03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 8A6BF380000B9; Sat, 5 Jun 2010 11:18:09 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1OKv72-0008Pw-Oi for rs_out_1@blacksheep.org; Sat, 05 Jun 2010 16:16:40 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1OKv72-0008Pn-2y for rsgb_lf_group@blacksheep.org; Sat, 05 Jun 2010 16:16:40 +0100 Received: from out1.ip06ir2.opaltelecom.net ([62.24.128.242]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1OKv70-0007SU-GO for rsgb_lf_group@blacksheep.org; Sat, 05 Jun 2010 16:16:40 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AgwFAEsHCkxcEYB//2dsb2JhbACPCwODAYxGcb11hRcE X-IronPort-AV: E=Sophos;i="4.53,367,1272841200"; d="scan'208,217";a="460577769" Received: from unknown (HELO xphd97xgq27nyf) ([92.17.128.127]) by out1.ip06ir2.opaltelecom.net with SMTP; 05 Jun 2010 16:16:15 +0100 Message-ID: <003101cb04c2$0913cc10$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <657E7065AC4C454AB63F6C7C2FF043F6@Black> Date: Sat, 5 Jun 2010 16:16:12 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: VLF: Two-Way QSO on Dreamer's Band Content-Type: multipart/alternative; boundary="----=_NextPart_000_002E_01CB04CA.6A824BE0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,HTML_MESSAGE 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-sid: 3039ac1d408f4c0a6ab14d43 X-AOL-IP: 193.82.116.20 ------=_NextPart_000_002E_01CB04CA.6A824BE0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Gary What sort of strength are u receiving the Alpha signals This might give u an idea how strong amateur signals are likely to be= by comparison There is not much information available from UK stations about their= receiving capability de mal/g3kev ----- Original Message -----=20 From: Gary - G4WGT=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Saturday, June 05, 2010 2:20 PM Subject: Re: VLF: Two-Way QSO on Dreamer's Band Marcus, Walter, LF, Well done for your VLF 8.97 Hz 2 - way communication. Keep up the good work. Monitoring most of the time here but nothing seen as yet, one day I= may see something. 73 Gary - G4WGT - North West England - IO83QO On 4 June 2010 21:59, Markus Vester wrote: Dear LF, this morning, June 4th between 6 and 8 UT, Walter (DJ2LF) and myse= lf (DF6NM) were able to successfully conduct a two-way contact (aka "Q= SO") on 8.97 kHz. The distance between us is 20.2 km, well outside the= reactive near field zone (lamda / 2pi =3D 5.3 km). Both of us were using our small backyard Marconi antennas at home,= for transmit and receive. Walter's antenna has 260 pF at an estimated= effective height of about 5 m. He achieved about 370 mA current, resu= lting in a radiated power of about 5 uW (EMRP). I also got 5 uW from= 270 mA into 240 pF at about 7 m. I resonated the antenna using the sa= me little "yoghurt coil" described a while ago, having 1.3 henry from= 9 x 480 turns of 0.2 mm magnet wire, and a room-temperature DC resist= ance of 820 ohms. Walter used a scaled up version of this coil, about= 25 cm diameter and 60 cm long, consisting of seven polypropylene hous= ehold buckets inserted into one another. Each bucket has 460 turns of= 0.4 mm wire on it, about 320 ohms total DC resistance. Each of us app= lied approximately 100 W of "RF" power from a car-HiFi amplifier. Reception was done by soundcard, without preamplification. We set= Spectrum Lab to 0.95 mHz FFT bandwidth, with noise blanking on, and= samplerate tracking based on the German 23.4 kHz MSK signal. We chose= to transmit 30 minute dashes, separated by 15 minute quiet intervals= to allow for FFT processing delay. We employed a special "micro-QSO" format, which was designed to ex= change the minimum single-bit report and confirmation in only three tu= rnovers, each containing a single dash. Station identification was by= frequency alone, with preassigned pairs (8969.92 / 8970.02 Hz for DJ2= LF, 8970.0 / 8970.1 Hz for DF6NM). Generally the lower frequency was= assigned to a negative response (ie. "not confirmed"), whereas the up= per one is positive ("received ok"). DF6NM started by transmitting a carrier on his lower frequency, fr= om 4:00 to 4:30 UT. This was indeed seen by DJ2LF, who replied on his= upper frequency from 4:45 to 5:15, reporting positive reception. Then= DF6NM confirmed reception on the upper frequency from 5:30 to 6:00.= The whole procedure took two hours. Attached are screenshots from both sides. Unfortunately the QRN le= vel this morning was much worse than we had hoped for, with active thu= nderstorms in South Italy, Poland and Belorussia. To my surprise, our= dashes still made it through and were unambiguously visible, with an= estimated SNR of 6 to 8 dB. Walter's signal can actually still be see= n between my own dashes on my VLF grabber http://www.mydarc.de/df6nm/v= lf/vlfgrabber.htm . As far as we know, this was probably the first two-way amateur QSO= on VLF, using truely radiated fields. Another dream came true... Best regards, Markus (DF6NM) ------=_NextPart_000_002E_01CB04CA.6A824BE0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Gary
What sort of strength are u receiving= the Alpha=20 signals
This might give u an idea how strong= amateur=20 signals are likely to be by comparison
There is not much information availab= le from UK=20 stations about their receiving capability
de mal/g3kev
 
 
----- Original Message -----
Sent: Saturday, June 05, 2010= 2:20=20 PM
Subject: Re: VLF: Two-Way QSO= on=20 Dreamer's Band

Marcus, Walter, LF,

Well done for your VLF 8.97 Hz 2 - way communication.

Keep up the good work.

Monitoring most of the time here but nothing seen as yet, one= day I may=20 see something.

73

Gary - G4WGT - North West England - IO83QO



On 4 June 2010 21:59, Markus Vester <markusv= ester@aol.com>=20 wrote:
Dear LF,
 
this morning, June 4th between 6= and 8 UT,=20 Walter (DJ2LF) and myself (DF6NM) were able to successfully conduc= t a=20 two-way contact (aka "QSO") on 8.97 kHz. The distance between us= is 20.2 km,=20 well outside the reactive near field zone (lamda / 2pi =3D 5.3=20 km).
 
Both of us were using our small= backyard=20 Marconi antennas at home, for transmit and receive. Walter's anten= na has 260=20 pF at an estimated effective height of about 5 m. He achieved abou= t 370 mA=20 current, resulting in a radiated power of about 5 uW (EMRP). I als= o got 5 uW=20 from 270 mA into 240 pF at about 7 m. I resonated the antenna usin= g the same=20 little "yoghurt coil" described a while ago, having 1.3 henry from= 9 x 480=20 turns of 0.2 mm magnet wire, and a room-temperature DC resistance= of 820=20 ohms. Walter used a scaled up version of this coil, about 25 cm di= ameter and=20 60 cm long, consisting of seven polypropylene household buckets in= serted=20 into one another. Each bucket has 460 turns of 0.4 mm wire on it,= about 320=20 ohms total DC resistance. Each of us applied approximately 100 W= of "RF"=20 power from a car-HiFi amplifier.
 
Reception was done by soundcard,= without=20 preamplification. We set Spectrum Lab to 0.95 mHz FFT bandwidth,= with noise=20 blanking on, and samplerate tracking based on the German 23.4 kHz= MSK=20 signal. We chose to transmit 30 minute dashes, separated by 15 min= ute quiet=20 intervals to allow for FFT processing delay.
 
We employed a special "micro-QSO"= format, which=20 was designed to exchange the minimum single-bit report and confirm= ation in=20 only three turnovers, each containing a single dash. Station ident= ification=20 was by frequency alone, with preassigned pairs (8969.92 / 8970.02= Hz for=20 DJ2LF, 8970.0 / 8970.1 Hz for DF6NM). Generally the lower frequenc= y was=20 assigned to a negative response (ie. "not confirmed"), whereas the= upper one=20 is positive ("received ok").
 
DF6NM started by transmitting a= carrier on his=20 lower frequency, from 4:00 to 4:30 UT. This was indeed seen by DJ2= LF, who=20 replied on his upper frequency from 4:45 to 5:15, reporting positi= ve=20 reception. Then DF6NM confirmed reception on the upper frequency= from 5:30=20 to 6:00. The whole procedure took two hours.
 
Attached are screenshots from bot= h sides.=20 Unfortunately the QRN level this morning was much worse than we ha= d hoped=20 for, with active thunderstorms in South Italy, Poland and Beloruss= ia. To my=20 surprise, our dashes still made it through and were unam= biguously=20 visible, with an estimated SNR of 6 to 8 dB. Walter's signal= can=20 actually still be seen between my own dashes on my VLF grabbe= r http://www.mydarc.de/df6nm/vlf/vlfgrabber.htm= =20 .
 
As far as we know, this was proba= bly the first=20 two-way amateur QSO on VLF, using truely radiated fields. Another= dream came=20 true...
 
Best regards,
Markus=20 (DF6NM)

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