Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-da01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 492C2380000C1; Wed, 12 Sep 2012 11:18:28 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TBogm-00078j-3D for rs_out_1@blacksheep.org; Wed, 12 Sep 2012 16:17:16 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TBogl-00078a-ER for rsgb_lf_group@blacksheep.org; Wed, 12 Sep 2012 16:17:15 +0100 Received: from smtpout3.wanadoo.co.uk ([80.12.242.59] helo=smtpout.wanadoo.co.uk) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1TBogj-0002MH-Mq for rsgb_lf_group@blacksheep.org; Wed, 12 Sep 2012 16:17:14 +0100 Received: from AGB ([2.26.22.87]) by mwinf5d45 with ME id yFHC1j0051skBk203FHCAX; Wed, 12 Sep 2012 17:17:12 +0200 Message-ID: From: "Graham" To: References: <007901cd90f7$34e24ba0$0501a8c0@xphd97xgq27nyf> In-Reply-To: <007901cd90f7$34e24ba0$0501a8c0@xphd97xgq27nyf> Date: Wed, 12 Sep 2012 16:17:11 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Mal, Things have moved on a bit You can use a class E/D amp in linear , with envelope restoration , that maintains the efficiency , s/n imd is about 35 dB . [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [80.12.242.59 listed in list.dnswl.org] 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: 09c1a181dc7b5fd4ce37590584a561d1 Subject: Re: LF: Fw: LOST TRACK Content-Type: multipart/alternative; boundary="----=_NextPart_000_00E8_01CD9102.10B54650" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,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-sid: 3039ac1d40495050a7c43a45 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_00E8_01CD9102.10B54650 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Mal, Things have moved on a bit=20 You can use a class E/D amp in linear , with envelope = restoration , that maintains the efficiency , s/n imd is about = 35 dB .=20 The Op structure allows for up to 50% loss of signal randomly = along the time line , ie first 50% , last 50% or randomly = distributed=20 Problem with short burst is the 'average energy' level , like a = radar , huge KW peak powers but only watts average power .....and = yes , wide bandwidth .. Detecting a carrier is one thing .. to recover data is a much more = difficult thing and requires a higher level of energy=20 G.. =20 From: mal hamilton=20 Sent: Wednesday, September 12, 2012 3:59 PM To: rsgb=20 Subject: LF: Fw: LOST TRACK ----- Original Message -----=20 From: mal hamilton=20 To: rsgb=20 Sent: Wednesday, September 12, 2012 2:57 PM Subject: LOST TRACK LF/MF I think most have now lost track of who is actually available to work or = listen at any one time on LF or MF with such a variety of modes talked = about and in use.=20 A new comer has no chance, would not know where to start or what to = listen for or what frequency.=20 In the days of CW or QRSS DXing, the procedure seemed orderly then the = scene became fragmented with the different DATA modes being introduced = and just as easly ended.=20 For simplicity and efficiency sake I would suggest sticking to CW, QRSS = and OPERA using class D or E type amplifiers at 90% efficiency.=20 and avoid modes that might appear efficient but are not when you = consider they need Linear amps that are only 40% efficient. Slow slow modes are not the best when hit by QRN or QSB that removes = large chunks of the data stream. in fact Short Burst transmissions would probably had an advantage, = anyone thought of that approach ie several repeative short bursts of = information sent periodically, of course more bandwidth is required. de mal/g3kev ------=_NextPart_000_00E8_01CD9102.10B54650 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Mal,
 
Things  have  moved on a bit
 
You  can  use a  class  E/D    = amp =20 in linear , with  envelope  restoration  , that =20 maintains  the  efficiency  , s/n   = imd =20  is  about   35 dB .
 
The  Op structure allows for  up to  50% loss  = of =20 signal   randomly  along the  time  line , = ie =20 first 50% , last  50% or  randomly  distributed
 
Problem with  short burst is the  'average energy' = level  ,=20 like a  radar  , huge KW peak  powers  but  = only =20 watts  average power .....and  yes  , wide  = bandwidth=20 ..
 
Detecting  a carrier  is one thing  .. to =20 recover  data is a much  more difficult  thing and = requires =20 a higher  level of energy
 
G..
 

 
From: mal hamilton
Sent: Wednesday, September 12, 2012 3:59 PM
To: rsgb
Subject: LF: Fw: LOST TRACK

 
----- Original Message -----=20
From: mal = hamilton=20
To: rsgb
Sent: Wednesday, September 12, 2012 2:57 PM
Subject: LOST TRACK

LF/MF
I think most have now lost track of who is = actually=20 available to work or listen at any one time on LF or MF with such a = variety of=20 modes talked about and in use.
A new comer has no chance, would not know where = to start=20 or what to listen for or what frequency.
In the days of CW or QRSS DXing,   the = procedure=20 seemed orderly then the scene became fragmented with the different DATA = modes=20 being introduced and just as easly ended.
For simplicity and efficiency sake I = would=20 suggest sticking to CW, QRSS and OPERA using class D or E type = amplifiers at 90%=20 efficiency.
and avoid modes that might appear efficient but = are not=20 when you consider they need Linear amps that are only 40%=20 efficient.
Slow slow modes are not the best when hit by QRN = or QSB=20 that removes large chunks of the data stream.
in fact Short Burst transmissions would probably = had an=20 advantage, anyone thought of that approach ie several repeative short = bursts of=20 information sent periodically, of course more bandwidth is=20 required.
de mal/g3kev
 
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