Return-Path: Received: from mtain-dj01.r1000.mx.aol.com (mtain-dj01.r1000.mail.aol.com [172.19.187.137]) by air-de03.mail.aol.com (v129.4) with ESMTP id MAILINDE033-5eac4bd7762836f; Tue, 27 Apr 2010 19:41:28 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mtain-dj01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 5CCF5380000AE; Tue, 27 Apr 2010 19:41:26 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1O6uNi-0003ew-Qr for rs_out_1@blacksheep.org; Wed, 28 Apr 2010 00:39:58 +0100 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1O6uNi-0003en-44 for rsgb_lf_group@blacksheep.org; Wed, 28 Apr 2010 00:39:58 +0100 Received: from smtp6.freeserve.com ([193.252.22.191]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1O6uNg-0000QJ-Ea for rsgb_lf_group@blacksheep.org; Wed, 28 Apr 2010 00:39:58 +0100 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3611.me.freeserve.com (SMTP Server) with ESMTP id 95E6B7000085 for ; Wed, 28 Apr 2010 01:39:44 +0200 (CEST) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3611.me.freeserve.com (SMTP Server) with ESMTP id 897197000089 for ; Wed, 28 Apr 2010 01:39:44 +0200 (CEST) Received: from AGB (unknown [91.110.67.176]) by mwinf3611.me.freeserve.com (SMTP Server) with SMTP id 2B2E67000085 for ; Wed, 28 Apr 2010 01:39:44 +0200 (CEST) X-ME-UUID: 20100427233944176.2B2E67000085@mwinf3611.me.freeserve.com Message-ID: <752E3E9B581846CD96E06CCCF8AB3105@AGB> From: "Graham" To: References: <4EB4F8217FCC42CAB07AE666A6AB07B8@AGB> <4BD5F358.8040508@freenet.de> <4BD6147C.7080201@usa.net> <4BD62289.6040703@usa.net> <2B460BBAF166453C9B99F67A38457609@PCCasa> <4BD6E2EF.9060300@usa.net> <933C274D780649AFA1D0DDCEE5D82AD4@PCCasa> In-Reply-To: <933C274D780649AFA1D0DDCEE5D82AD4@PCCasa> Date: Wed, 28 Apr 2010 00:39:43 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8089.726 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8089.726 X-Antivirus: avast! (VPS 100427-1, 27/04/2010), Outbound message X-Antivirus-Status: Clean X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: Probably not a new question... Content-Type: multipart/alternative; boundary="----=_NextPart_000_0053_01CAE66B.4B8CD390" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.1 required=5.0 tests=HTML_20_30,HTML_MESSAGE, HTML_TITLE_EMPTY,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: 3039cdbc9d054bd77626194a X-AOL-IP: 193.82.116.20 ------=_NextPart_000_0053_01CAE66B.4B8CD390 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable One thing to watch is the military radios are sometimes not 100= % compatible with ham operation , which oddly can be more demandi= ng in term's of filtering , dynamic range , and add on's like noise= suppression and post audio processing , I have three commercial = radios , skanti R5003 - suffers from cross mode from the local= MW tx .. supposed to be used at sea .. RA6790GM which has one of= most mechanical AGC systems ever and is is very noisy to the poin= t of fatiguing with headphones .. but can be set to 1 Hz and the= bfo is synth as well in 100 hz steps , RA1778 handles nicely ..= but has a 1.4 meg vfo for the bfo .. ssb is phase locked , so= cannot use the narrow filter's for data ...and so it go's on= ... the MA1723 exciter took a second MA1723 to get it going ...= . etc=20 .to be honest for most thing's the ft897-d , with its add on dsp= works fine ....! G . From: Daniele Tincani=20 Sent: Tuesday, April 27, 2010 3:02 PM To: rsgb_lf_group@blacksheep.org=20 Subject: Re: LF: Probably not a new question... OK, now I see the concept much clearer than I knew before (with my apo= logies for having stressed the subject a bit :-)). All this stuff is very interesting and promising, with very high perfo= mance/cost ratio and great scalability. I think I will be seriously ev= aluating to homebrew a good SDR project in the coming months (the only= choice I can afford from a financial point of view :-)) Cheers D. ----- Original Message -----=20 From: Alberto di Bene=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Tuesday, April 27, 2010 3:13 PM Subject: Re: LF: Probably not a new question... On 4/27/2010 2:25 AM, Daniele Tincani wrote:=20 Hi Alberto, I'm quite familiar with digital signal processing (I work in the= embedded SW area for a big manufacturer of telecommunications equipme= nts and digital streams of several Gbit/s are common on our boards),= nevertheless I know that analog conditioning of signals (before they= become "numbers") is at least as important as the digital treatment,= unless you accept to sample meaningless information (noise) at the AD= C :-) Anyway I'm sure this is dealt with perfectly in SDR's so I think= we can stop here this discussion. Thank you for clarifications. Cheers D, Hi Daniele, I wasn't specifically addressing you in my past message, I was ju= st trying to explain what is behind some diffidence that often it is= possible to hear or to read about the SDR technology. And the Softrocks are a mixed blessing...= from one side they helped a lot with their very low cost the diffusio= n of the SDR concepts among the ham community. But on the opposite side, their lackluster= performance generated in some the impression that SDR is a technology= still much behind its classical analog counterpart, which isn't....=20 You are perfectly right when saying that the analog portion in front= of the digitizer is of utmost importance, to not have to deal with me= aningless numbers. That's why the tendency is to bring the digitization stage as close= as possible to the antenna... and, at least for the HF bands, this go= al is almost reached with the QuickSilver and the Perseus SDR.... 73 Alberto I2PHD ----------------------------------------------------------------------= -------- Nessun virus nel messaggio in arrivo. Controllato da AVG - www.avg.com=20 Versione: 9.0.814 / Database dei virus: 271.1.1/2837 - Data di rila= scio: 04/26/10 20:27:00 ------=_NextPart_000_0053_01CAE66B.4B8CD390 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
One  thing to&nb= sp; watch is=20 the  military radios are  sometimes not  100 % compatib= le =20 with ham operation  , which oddly  can be  more demandi= ng in=20 term's  of filtering , dynamic range , and  add on's = like noise=20 suppression and  post audio  processing , I have  three= =20 commercial  radios , skanti  R5003 - suffers  from cros= s =20 mode  from the  local MW tx  .. supposed to  be us= ed=20 at  sea ..  RA6790GM which has one of most  mechanical= AGC=20 systems ever  and is is very  noisy to the  point of fa= tiguing=20  with  headphones .. but  can be set to  1 Hz and= the =20 bfo  is  synth as  well in 100  hz steps , RA1778&= nbsp;=20 handles nicely .. but  has a  1.4 meg vfo  for the=   bfo=20 .. ssb is  phase locked  , so  cannot  use the&nbs= p; narrow=20 filter's  for  data ...and  so  it  go's = ; on ...=20 the MA1723  exciter  took a  second MA1723  to&nbs= p; get=20 it  going .... etc
 
.to be honest&n= bsp; for =20 most thing's the  ft897-d , with its  add  on dsp&= nbsp;=20  works fine ....!
G .

Sent: Tuesday, April 27, 2010 3:02 PM
Subject: Re: LF: Probably not a new question...

OK, now I see the con= cept much=20 clearer than I knew before (with my apologies for having stressed the= subject a=20 bit :-)).
All this stuff is ver= y interesting=20 and promising, with very high perfomance/cost ratio and great scalabil= ity. I=20 think I will be seriously evaluating to homebrew a good SDR project in= the=20 coming months (the only choice I can afford from a financial point of= view=20 :-))
Cheers
D.
----- Original Message -----
From:=20 Alberto di= Bene=20
Sent: Tuesday, April 27, 2010= 3:13=20 PM
Subject: Re: LF: Probably not= a new=20 question...

On 4/27/2010 2:25 AM, Daniele Tincani wrote:=20
Hi Alberto,
 
I'm quite fami= liar with=20 digital signal processing (I work in the embedded SW=20 area for a big manufacturer of telecommunicati= ons=20 equipments and digital streams of several Gbit/s are common on our= boards),=20 nevertheless I know that analog conditioning of signals (before th= ey become=20 "numbers") is at least as important as the digital treatment, unle= ss you=20 accept to sample meaningless information (noise) at the ADC :-) An= yway I'm=20 sure this is dealt with perfectly in SDR's so I think we can stop= here this=20 discussion.
Thank you for= =20 clarifications.
Cheers<= /I>
D,<= /I>
Hi=20 Daniele,

   I wasn't specifically addressing you in= my past=20 message, I was just trying to explain what is behind some diffidence= that=20 often it is possible to hear or to read
about the SDR technology.=   And=20 the Softrocks are a mixed blessing... from one side they helped a lo= t with=20 their very low cost the diffusion of the SDR concepts
among the= ham=20 community. But on the opposite side, their lackluster performance ge= nerated in=20 some the impression that SDR is a technology still much behind
it= s=20 classical analog counterpart, which isn't....

You are perfec= tly right=20 when saying that the analog portion in front of the digitizer is of= utmost=20 importance, to not have to deal with meaningless numbers.
That's= why the=20 tendency is to bring the digitization stage as close as possible to= the=20 antenna... and, at least for the HF bands, this goal is almost reach= ed=20 with
the QuickSilver and the Perseus SDR....

73  Albe= rto =20 I2PHD


Nessun virus nel messaggio in arrivo.
Controllato da= AVG -=20 www.avg.com
Versione: 9.0.814 / Database dei virus: 271.1.1/2837= - =20 Data di rilascio: 04/26/10 20:27:00


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