Return-Path: Received: from mtain-db12.r1000.mx.aol.com (mtain-db12.r1000.mx.aol.com [172.29.64.96]) by air-da06.mail.aol.com (v129.4) with ESMTP id MAILINDA064-86664ccc6d411ca; Sat, 30 Oct 2010 15:08:49 -0400 Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-db12.r1000.mx.aol.com (Internet Inbound) with ESMTP id 854B1380000CF; Sat, 30 Oct 2010 15:08:46 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1PCGm2-0006Np-BU for rs_out_1@blacksheep.org; Sat, 30 Oct 2010 20:07:30 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1PCGm1-0006Nf-O9 for rsgb_lf_group@blacksheep.org; Sat, 30 Oct 2010 20:07:29 +0100 Received: from mailout-de.gmx.net ([213.165.64.23] helo=mail.gmx.net) by relay1.thorcom.net with smtp (Exim 4.63) (envelope-from ) id 1PCGlz-0002tQ-DM for rsgb_lf_group@blacksheep.org; Sat, 30 Oct 2010 20:07:29 +0100 Received: (qmail invoked by alias); 30 Oct 2010 19:07:20 -0000 Received: from p5DC430D1.dip.t-dialin.net (EHLO Clemens04) [93.196.48.209] by mail.gmx.net (mp001) with SMTP; 30 Oct 2010 21:07:20 +0200 X-Authenticated: #17214767 X-Provags-ID: V01U2FsdGVkX1/PIJB654fPQE8b8lybcfwQwymTKDeGbc5xVNJsq3 8ZmbrNaS3WrdMW Message-ID: <00f001cb7865$ad833bc0$0201a8c0@Clemens04> From: "Clemens Paul" To: References: <4CCAED49.6030007@o2.ie><4CCC2277.9040801@o2.ie><045201cb7844$ca1df020$0201a8c0@Clemens04><006b01cb7857$f564e870$4001a8c0@lark> Date: Sat, 30 Oct 2010 21:07:17 +0200 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.3664 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2900.3664 X-Y-GMX-Trusted: 0 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="----=_NextPart_000_00EC_01CB7876.6F0A9670" 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: 3039ac1d40604ccc6d3d7c70 X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : temperror ------=_NextPart_000_00EC_01CB7876.6F0A9670 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Hello Andy, your test results show quite strong differencies between the upper and lower IM3 product,up to 18dB. Unsymmetrical IM3 products *always* imply that there is more than one IM3 producing source. Maybe it's a good idea to check the inherent IM3 behaviour of your tes= t setup itself. 3dB-combiners have only 30-35dB port isolation,true hybrid combiners= (6dB) are better by at least 20dB,if they are made tunable up to 80dB isolat= ion is achievable. Also the 70dB resistive isolation between the two crystal oscillators= seems to be a bit on the short side. 73 Clemens DL4RAJ ---- Original Message -----=20 From: Andy Talbot To: rsgb_lf_group@blacksheep.org Sent: Saturday, October 30, 2010 7:47 PM Subject: Re: LF: RFspace SDR-IQ 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 wro= te: 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 dan= ger 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 remarkabl= e 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 spa= ce 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 > > ----------------------------------------------------------------------= -------- Eingehende eMail ist virenfrei. Von AVG =FCberpr=FCft - www.avg.de Version: 9.0.864 / Virendatenbank: 271.1.1/3227 - Ausgabedatum: 10/3= 0/10 08:34:00 ------=_NextPart_000_00EC_01CB7876.6F0A9670 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Hello Andy,
 
your test results show quite strong= differencies=20 between the
upper and lower IM3 product,up to=20 18dB.
Unsymmetrical IM3 products *alwa= ys*=20 imply  that there is more than one
IM3 producing source.
Maybe it's a good idea to check the= inherent IM3=20 behaviour of your test
setup itself.
3dB-combiners have only 30-35dB port= isolation,true=20 hybrid combiners (6dB)
are better by at least 20dB,if they= are made=20 tunable up to 80dB isolation
is achievable.
Also the 70dB resistive isolation bet= ween the two=20 crystal oscillators seems to
be a bit on the short side.&nb= sp;
 
73
Clemens
DL4RAJ
 
 
 
---- Original Message -----
From:=20 Andy Talbot
Sent: Saturday, October 30,= 2010 7:47=20 PM
Subject: Re: LF: RFspace SDR-= IQ

 
Showing some of the minor peculiarities of DS SDRs
On 30 October 2010 18:04, Alan Melia <al= an.melia@btinternet.com>=20 wrote:
Hi=20 Clemens, you seem to impute that there are no shortcommings in=20 direct
sampling!
 :-))    I suspect there are= , but they=20 are just "different".  You may be
right about the units me= ntioned,=20 but it is just as easy to make a poorly
preforming DSP radio as= to make a=20 poor analogue one. We are in danger of
being conditioned to acc= ept that=20 "digital" is the magic dust that solves all
problems......it is= =20 definitely not so!

Having said that, the performance of som= e units is=20 quite remarkable and I do
own a couple very good conventional= =20 receivers.

Alan G3NYK

----- Original Message -----
From: "Clemens= Paul"=20 <cpaul@gmx.net>
To:= <rsgb_lf_gro= up@blacksheep.org>
Sent: Saturday, October 30, 2010 4:11 PM
Subjec= t: Re: LF:=20 RFspace SDR-IQ


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




Eingehende eMail ist virenfrei.
Von AVG =FCberpr=FCft= - www.avg.de=20
Version: 9.0.864 / Virendatenbank: 271.1.1/3227 - Ausgabedatum:= 10/30/10=20 08:34:00
------=_NextPart_000_00EC_01CB7876.6F0A9670--