Return-Path: Received: (qmail 232 invoked from network); 15 May 2000 19:39:14 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by bells.core.plus.net.uk with SMTP; 15 May 2000 19:39:14 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 12rQcF-0008Dn-00 for rsgb_lf_group-outgoing@blacksheep.org; Mon, 15 May 2000 20:33:23 +0100 Received: from postfix3.free.fr ([212.27.32.22] ident=postfix) by post.thorcom.com with esmtp (Exim 3.02 #1) id 12rQcA-0008Dc-00 for rsgb_lf_group@blacksheep.org; Mon, 15 May 2000 20:33:19 +0100 Received: from f5maf (toulouse-1-5-160.dial.proxad.net [213.228.5.160]) by postfix3.free.fr (Postfix) with SMTP id ED7E186BA8 for ; Mon, 15 May 2000 21:32:44 +0200 (CEST) Message-ID: <002601bfbea4$c24e7960$a005e4d5@f5maf> From: "f5maf" To: rsgb_lf_group@blacksheep.org Subject: LF: Re: Re: Re: Optimal width for LF? Date: Mon, 15 May 2000 21:26:24 +0200 MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-2; format=flowed Content-Transfer-Encoding: 8bit X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Thanks Petr for these answers. I am very interested to make a new receiver:! 73 marc F5MAFf -----Message d'origine----- De : Petr Maly R : rsgb_lf_group@blacksheep.org Date : lundi 15 mai 2000 18:22 Objet : LF: Re: Re: Optimal width for LF? >I mix 10 MHz VXO with 8863 kHz XO. Stability looks sufficient, all this >gear will be placed in closed robust alluminium box which will be surrounded >by polystyrene casing to provide temperature isolation. I wanted to have no >tuning step to be able to use extremely narrow filters. > >73, Petr, OK1FIG > > >----- Original Message ----- >From: mv tsi >To: >Sent: Monday, May 15, 2000 1:32 PM >Subject: LF: Re: Optimal width for LF? > > >> Hello petr, >> I am interested to make a receiver. >> But what technology can you use for hight stability frequency? >> VFO,DDS? >> My first receiver used a 3Mhz VFO and a IF at 11Mhz. >> (I had a 137Khz 14 Mhz converter). >> I had some probleme to have a narrow band pass with 5 cristals (800Hz). >> For reduct audio band pass I used a MF10. >> But with this receiver I couldn't survey a frequency during more hours. >> The VFO stability had no perfect. >> 73 marc. >> ----- Original Message ----- >> From: Petr Maly >> To: 136 group >> Sent: Friday, May 12, 2000 2:34 PM >> Subject: LF: Optimal width for LF? >> >> >> > Hello all >> > I am just designing a new RX for 136 kHz band. It will have IF on 1 MHz >> with >> > high quality x-tal filter with bandwidth 200 Hz. The main selectivity >will >> > by obtained on AF with passive filter with coils on pot cores. Till now >I >> > used similar filter with bandwidth about 50 Hz and it seems to be still >> too >> > wide for LF. I was about to make it new with 15 Hz width. Somebody here >> > mentioned 1 Hz wide filter which seems to me to be too narrow. At least, >> the >> > filter cannot be narrower than obtainable osc stability. Can we make a >> > little questionnaire here? What bandwidth do you use and what is the >> > experience? >> > >> > 73, Petr, OK1FIG >> > >> > >> > >> > >> > >> > >> > >> >> >> > > >