Return-Path: Received: from mtain-dj09.r1000.mx.aol.com (mtain-dj09.r1000.mail.aol.com [172.19.187.145]) by air-md08.mail.aol.com (v129.4) with ESMTP id MAILINMD083-8b924ccc5a7d312; Sat, 30 Oct 2010 13:48:45 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dj09.r1000.mx.aol.com (Internet Inbound) with ESMTP id 6078B38000083; Sat, 30 Oct 2010 13:48:44 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PCFWQ-0005tB-T3 for rs_out_1@blacksheep.org; Sat, 30 Oct 2010 18:47:18 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PCFWQ-0005t2-7q for rsgb_lf_group@blacksheep.org; Sat, 30 Oct 2010 18:47:18 +0100 Received: from mail-iw0-f171.google.com ([209.85.214.171]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1PCFWN-0002Zo-Av for rsgb_lf_group@blacksheep.org; Sat, 30 Oct 2010 18:47:18 +0100 Received: by iwn35 with SMTP id 35so1523420iwn.16 for ; Sat, 30 Oct 2010 10:47:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=googlemail.com; s=gamma; h=domainkey-signature:mime-version:received:received:in-reply-to :references:date:message-id:subject:from:to:content-type; bh=jboao7kbDibRKkaaNPhEoUc0UmvQABJsysGL9ahldLU=; b=f8lZcqifgYwEFeLeVKhXCIR/ujpkEfhd+ekuyb4cILrO2MDPEn64dzeqkA1HzHyck2 XySExAT9QhdQnUgET9q4K6iWEO/tgkmxqNDc4wzEYb1WmZ8IAAScdVdsVZB5ZjQqZn7b W2ZN53QwefaoeVlexRhOeD9Gh1zxk8rIltXqQ= DomainKey-Signature: a=rsa-sha1; c=nofws; d=googlemail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :content-type; b=wHlZifMFTz3iTpV+bZxm5yc9rQEGhWUxWsAj6+bFLa+/uK1gOSQ87tZt7j7LfDCKm8 0ijnQjQC+9b06JmOmXeED3U0GmvbPwIlMR0llBIcPKqRMfqwS+Tt/j+aNzkgr14gCEnb 76mKAx9pEMNQmKUeZfsYmQNEavLoX5qCKrDYI= MIME-Version: 1.0 Received: by 10.231.35.200 with SMTP id q8mr12190401ibd.191.1288460832019; Sat, 30 Oct 2010 10:47:12 -0700 (PDT) Received: by 10.231.79.69 with HTTP; Sat, 30 Oct 2010 10:47:11 -0700 (PDT) In-Reply-To: <006b01cb7857$f564e870$4001a8c0@lark> References: <4CCAED49.6030007@o2.ie> <4CCC2277.9040801@o2.ie> <045201cb7844$ca1df020$0201a8c0@Clemens04> <006b01cb7857$f564e870$4001a8c0@lark> Date: Sat, 30 Oct 2010 18:47:11 +0100 Message-ID: From: Andy Talbot To: rsgb_lf_group@blacksheep.org DomainKey-Status: good (testing) X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: Re: LF: RFspace SDR-IQ Content-Type: multipart/alternative; boundary=002215048a43331ebf0493d92ab8 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-SCOLL-AUTHENTICATION: mail_rly_antispam_dkim-m242.1 ; domain : googlemail.com DKIM : pass x-aol-sid: 3039cdbc9d0e4ccc5a7b5a15 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none X-Mailer: Unknown (No Version) --002215048a43331ebf0493d92ab8 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable http://www.g4jnt.com/SDRIQ_Linearity.pdf Showing some of the minor peculiarities of DS SDRs Andy www.g4jnt.com On 30 October 2010 18:04, Alan Melia wrote: > Hi Clemens, you seem to impute that there are no shortcommings in direct > sampling! > :-)) I suspect there are, but they are just "different". You may be > right about the units mentioned, but it is just as easy to make a poorly > preforming DSP radio as to make a poor analogue one. We are in danger of > being conditioned to accept that "digital" is the magic dust that solves > all > problems......it is definitely not so! > > Having said that, the performance of some units is quite remarkable and= I > do > own a couple very good conventional receivers. > > Alan G3NYK > > ----- Original Message ----- > From: "Clemens Paul" > To: > Sent: Saturday, October 30, 2010 4:11 PM > Subject: Re: LF: RFspace SDR-IQ > > > > Tony, > > > > the most important difference between SDR-IQ/-IP(from RF Space) > > or Perseus and the $200 SDR on > > http://www.lazydogengineering.com/LD-1A_SDR.html > > is that the latter is no direct sampling receiver. > > It uses a downconverting technique with a number of shortcomings,e.g. > > phase noise of the LO and others. > > I would go for a direct sampling SDR like those e.g. from RF space or > > Perseus. > > > > 73 > > Clemens > > DL4RAJ > > > > ----- Original Message ----- > > From: "Tony" > > To: > > Sent: Saturday, October 30, 2010 3:49 PM > > Subject: Re: LF: RFspace SDR-IQ > > > > > > > Thanks guys. > > > > > > You have just tipped the balance for me and I shall be placing an > > > order > > > for one on Monday morning. > > > It's about time I joined the 21st century, but it will be > > > interesting to > > > compare it to my beloved FT 102 rx. > > > > > > Tony, EI8JK. > > > > > > > > > On 29/10/2010 16:50, Tony wrote: > > >> Hello group. > > >> > > >> Has anyone any experience with this SDR ? > > >> It looks interesting and I'm a bit tempted, especially as it works > > >> full spec down to 500 Hz and "usable" to 100 Hz. > > >> But as I have never used an SDR, I haven't got a clue if it's any > > >> good > > >> or not. > > >> > > >> > > >> > > > > > > > > > > > > > ------------------------------------------------------------------------= -- > ------ > > > > > > > > Eingehende eMail ist virenfrei. > > Von AVG =FCberpr=FCft - www.avg.de > > Version: 9.0.864 / Virendatenbank: 271.1.1/3226 - Ausgabedatum: > > 10/29/10 20:34:00 > > > > > > > --002215048a43331ebf0493d92ab8 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable
=A0
Showing some of the minor peculiarities of DS SDRs
On 30 October 2010 18:04, Alan Melia <alan.melia@btint= ernet.com> wrote:
Hi Clemens, you seem to impute= that there are no shortcommings in direct
sampling!
=A0:-)) =A0 =A0= I suspect there are, but they are just "different". =A0You may= be
right about the units mentioned, but it is just as easy to make a poorlypreforming DSP radio as to make a poor analogue one. We are in danger of=
being conditioned to accept that "digital" is the magic dust= that solves all
problems......it is definitely not so!

Having said that, the perfor= mance of some units is quite remarkable and I do
own a couple very good= conventional receivers.

Alan G3NYK

----- Original Message -----
From: "Clemens= Paul" <cpaul@gmx.net>
= To: <rsgb_lf_group@blac= ksheep.org>
Sent: Saturday, October 30, 2010 4:11 PM
Subject: Re:= LF: RFspace SDR-IQ


> Tony,
>
> the most importa= nt difference between SDR-IQ/-IP(from RF Space)
> or Perseus and the= $200 SDR on
> http://www.lazydogengineering.com/LD-1A_SDR.html
>= is that =A0the latter is no direct sampling receiver.
> It uses a= downconverting technique with a number of shortcomings,e.g.
> phase noise of the LO and others.
> I would go for a direct sam= pling SDR like those e.g. from RF space or
> Perseus.
>
>= ; 73
> Clemens
> DL4RAJ
>
> ----- Original Message= -----
> From: "Tony" <ei8jk@o2.ie= >
> To: <r= sgb_lf_group@blacksheep.org>
> Sent: Saturday, October 30, 20= 10 3:49 PM
> Subject: Re: LF: RFspace SDR-IQ
>
>
> > Thanks= guys.
> >
> > You have just tipped the balance for me= and I shall be placing an
> > order
> > for one on Mond= ay morning.
> > It's about time I joined the 21st century, but it will be> > interesting to
> > compare it to my beloved FT 102 rx.=
> >
> > Tony, EI8JK.
> >
> >
>= > On 29/10/2010 16:50, Tony wrote:
> >> Hello group.
> >>
> >> Has anyone an= y experience with this SDR ?
> >> It looks interesting and I&#= 39;m a bit tempted, especially as it works
> >> full spec down= to 500 Hz and "usable" to 100 Hz.
> >> But as I have never used an SDR, I haven't got a clue if= it's any
> >> good
> >> or not.
> >&= gt;
> >>
> >>
> >
> >
> >
> -------------------------------------------------------------= -------------
------
>
>
>
> Eingehende eMail= ist virenfrei.
> Von AVG =FCberpr=FCft - www.avg.de
> Version: 9.0.864 / Virendatenbank: 271.1.1/3226 - Ausgabedatum:
&g= t; 10/29/10 20:34:00
>
>


<= /div>
--002215048a43331ebf0493d92ab8--