Return-Path: Received: from mtain-di04.r1000.mx.aol.com (mtain-di04.r1000.mx.aol.com [172.29.64.8]) by air-dc10.mail.aol.com (v129.4) with ESMTP id MAILINDC101-86064d77d82e86; Wed, 09 Mar 2011 14:42:38 -0500 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-di04.r1000.mx.aol.com (Internet Inbound) with ESMTP id D050A380000D2; Wed, 9 Mar 2011 14:42:30 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PxPG3-0002bi-Gm for rs_out_1@blacksheep.org; Wed, 09 Mar 2011 19:41:19 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PxPG1-0002bZ-U8 for rsgb_lf_group@blacksheep.org; Wed, 09 Mar 2011 19:41:17 +0000 Received: from out1.ip07ir2.opaltelecom.net ([62.24.128.243]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PxPFz-0000f7-GL for rsgb_lf_group@blacksheep.org; Wed, 09 Mar 2011 19:41:17 +0000 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AvoAAJtmd01cHYpN/2dsb2JhbACCT2yRE4N2jix0xB2DAYJkBIFwjiyDAg X-IronPort-AV: E=Sophos;i="4.62,291,1297036800"; d="scan'208,217";a="482592485" Received: from unknown (HELO xphd97xgq27nyf) ([92.29.138.77]) by out1.ip07ir2.opaltelecom.net with SMTP; 09 Mar 2011 19:41:08 +0000 Message-ID: <005e01cbde91$ee21fc60$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: <003201cbde72$606d6090$0401a8c0@xphd97xgq27nyf> <543492.45357.qm@web28102.mail.ukl.yahoo.com> <998C9385-2AEE-4C44-91FE-86FE85F09BA9@gmail.com> Date: Wed, 9 Mar 2011 19:41:05 -0000 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: LF: Re: VLF Stability and soundcard locking Content-Type: multipart/alternative; boundary="----=_NextPart_000_005B_01CBDE91.EDC29E50" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.6 required=5.0 tests=HTML_20_30,HTML_FONT_BIG, 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: 3039ac1d40084d77d8266241 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none ------=_NextPart_000_005B_01CBDE91.EDC29E50 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Roger It is not difficult in a sensible time. Had OE5ODL been in QRS 3 or10 mode we could have had a QSO. I could ha= ve replied on 137.7 since I do not have a permit for 9 khz. I have worked Moscow and beyond on normal CW on 137.7 khz. All that is= required is enough ERP then its job done. If QRP merchants want to spend hours and weeks transmitting carriers= and no ID that is a different argument. G3KEV ----- Original Message -----=20 From: Roger Lapthorn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Wednesday, March 09, 2011 6:48 PM Subject: Re: LF: Re: VLF Stability and soundcard locking Pete It depends what the objectives are. In my view amateur radio communi= cation has been much advanced as a result of the recent experiments at= VLF. I agree that having some meaningful 2-way exchange of data is a= good objective but, as we are all finding out through our experiments= , this is difficult at any distance in a sensible time.=20 73 Roger G3XBM Via my 2.4GHz handheld (iPod Touch 4g) On 9 Mar 2011, at 18:36, M0FMT wrote: Mal..... for my ten cents worth.=20 Without being able to add modulation or on-off keying then no QSO= is taking place.=20 I suppose you could say if there is a carrier then some one is in= the shack but that's not really a QSO. I was hoping at the start of this exercise that a CW or other PSK= or similar real time QSO could be carried out over say 10/20kms. From= the tests Chris G3XIZ has done the best looks like a real time QSO wo= uld only happen over a 1.5km path cross town. Academically these tests are very interesting but I don't think IM= HO they are advancing Amateur Radio Communications. It will be limited= to a very select number of enthusiasts who are set up to TX and RX th= is type of transmission. However I will continue to try and pick up Ch= ris 11kms away. It will help me understand how to make a sensitive rec= eiver (something I need badly) 73 es GL Pete M0FMT IO91UX=20 ----------------------------------------------------------------------= ------ From: mal hamilton To: rsgb_lf_group@blacksheep.org Sent: Wed, 9 March, 2011 15:55:12 Subject: LF: Re: VLF Stability and soundcard locking I agree with these comments, and have said it before. If all radio amateurs on all the other bands used this system of= uh bandwidths and day long qso's Amateur Radio would cease as a hobby= . The aim should be to generate enough ERP so that a qso could take= place in a reasonably short time and be observed by others in say QRS= 3 - 60. SWL listeners/viewers could also particpate. The Dreamers band will fizzle out if transmitted signals are not= improved so that a larger audience can engage in the activities.=20 also who is going to buy a PCM2900 or similar gadgets for a ONE OF= F QSO if you are lucky. Again QSL reports on frequency alone are not VALID - it could be= any carrier. G3KEV ----- Original Message -----=20 From: Andy Talbot=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, March 08, 2011 8:42 PM Subject: LF: VLF Stability and soundcard locking It would appear that a typical soundcard isn't stable enough for= VLF use when stations are running 1mHz bandwidth signalling, and usin= g any locking option to other off-air signals is a bit restrictive in= what software you can run. It may be worth looking at a custom codec driven from a locked= frequency source. The PCM2900 (which costs only a few pounds from= Farnell, and they supply the data sheet) is a self contained USB code= c which needs only a handful of additional components for a USB soundc= ard with stereo line input and output. For normal operation it nee= ds a 12MHz crystal, but an external 12MHz source can be used which cou= ld be locked to, or derived from, a high stability reference. Even a= TCXO on its own with typically 1ppm accuracy / stability would be bet= ter than any normal 20ppm crystal I've built one of these codecs, but have yet to confirm the resu= lting sampling rate(s) are exactly what they should be. By the time= it has gone through USB packetising and Windows' drivers I hope full= synchronicity is maintained right through to the user software. Thi= s may only be the case for sampling rates like 12000Hz - it all depend= s what windows does. Exact conversion is needed for this solution to= be worthwhile, not just a close approximation. Andy www.g4jnt.com ------=_NextPart_000_005B_01CBDE91.EDC29E50 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Roger
It is not difficult in a sensible time.=
Had OE5ODL been in QRS 3 or10 mode we could ha= ve had a=20 QSO. I could have replied on 137.7 since I do not have a permit for 9= =20 khz.
I have worked Moscow and beyond on normal CW&n= bsp;on 137.7=20 khz. All that is required is enough ERP then its job done.=
If QRP merchants want to spend hours and weeks= =20 transmitting carriers and no ID that is a different argument.
G3KEV
 
----- Original Message -----
Sent: Wednesday, March 09, 20= 11 6:48=20 PM
Subject: Re: LF: Re: VLF Stab= ility and=20 soundcard locking

Pete

It depends what the objectives are. In my view amateur radio=20 communication has been much advanced as a result of the recent exper= iments at=20 VLF. I agree that having some meaningful 2-way exchange of data is= a good=20 objective but, as we are all finding out through our experiments, th= is is=20 difficult at any distance in a sensible time. 

73
Roger G3XBM

Via my 2.4GHz handheld (iPod Touch 4g)

On 9 Mar 2011, at 18:36, M0FMT <m0fmt@yahoo.co.uk> wrote:

Mal.....  for my ten cents worth.
 
Without being able to add modulation or on-off keying then no= QSO is=20 taking place.
 
I suppose you could say if there is a carrier then some one= is in the=20 shack but that's not really a QSO.
 
I was hoping at the start of this exercise that a CW or other= PSK or=20 similar real time QSO could be carried out over say 10/20kms.=  From=20 the tests Chris G3XIZ has done the best looks like a real time QSO= would=20 only happen over a 1.5km path cross town.
 
Academically these tests are very interesting but I don't thi= nk IMHO=20 they are advancing Amateur Radio Communications. It will be limite= d=20 to a very select number of enthusiasts who are set= up to TX=20 and RX this type of transmission. However I will continue to try= and pick up=20 Chris 11kms away. It will help me understand how to make a sensiti= ve=20 receiver (something I need badly)
 
73 es GL Pete M0FMT IO91UX=20


From: mal hamilton= <g3kevmal@talktalk.= net>
To: rsgb_lf_group@blacksheep.org<= /A>
Sent:= Wed, 9 March, 2011=20 15:55:12
Subject: LF: Re:=20 VLF Stability and soundcard locking

I agree with these comments, and have said= it=20 before.
If all radio amateurs on all the other ban= ds used this=20 system of uh bandwidths and day long qso's Amateur Radio would cea= se as a=20 hobby.
The aim should be to generate enough ERP= so=20 that a qso could take place in a reasonably short time and be= observed=20 by others in say QRS 3 - 60. SWL listeners/viewers could also=20 particpate.
The Dreamers band will fizzle out if = transmitted=20 signals are not improved so that a larger audience can engage in= the=20 activities. 
also who is going to buy a PCM2900 or=20 similar gadgets for a ONE OFF QSO if you are lucky.
Again QSL reports on frequency alone are= not VALID -=20 it could be any carrier.
G3KEV
 
 
----- Original Message -----
Sent: Tuesday, March 08,= 2011 8:42=20 PM
Subject: LF: VLF Stabilit= y and=20 soundcard locking

It would appear that a typical soundcard isn't stable= enough for=20 VLF use when stations are running 1mHz bandwidth signalling, and= using any=20 locking option to other off-air signals is a bit restrictive in= what=20 software you can run.
 
It may be worth looking at a custom codec driven from a loc= ked=20 frequency source.   The PCM2900 (which costs only a fe= w=20 pounds from Farnell, and they supply the data sheet) is a= self=20 contained USB codec which needs only a handful of additional com= ponents=20 for a USB soundcard with stereo line input and=20 output.     For normal operation it needs a= 12MHz=20 crystal, but an external 12MHz source can be used which cou= ld be=20 locked to, or derived from, a high stability reference.  Ev= en a TCXO=20 on its own with typically 1ppm accuracy / stability would= be better=20 than any normal 20ppm crystal
 
I've built one of these codecs, but have yet to confir= m the=20 resulting sampling rate(s) are exactly=20 what they should be.  By the time it has gone through= USB=20 packetising and Windows'  drivers I hope full synchronicity= is=20 maintained right through to the user software.   This= may only=20 be the case for sampling rates like 12000Hz - it all depends wha= t windows=20 does.   Exact conversion is needed for this solution= to be=20 worthwhile, not just a close approximation.
 
Andy

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