Return-Path: Received: (qmail 15741 invoked from network); 1 Aug 2001 12:54:17 -0000 Received: from unknown (HELO warrior-inbound.services.quay.plus.net) (212.159.14.227) by excalibur-qfe1-smtp-plusnet.harl.plus.net with SMTP; 1 Aug 2001 12:54:17 -0000 Received: (qmail 8226 invoked from network); 1 Aug 2001 12:54:01 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by warrior with SMTP; 1 Aug 2001 12:54:01 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.16 #2) id 15RvHY-0008Mr-00 for rsgb_lf_group-outgoing@blacksheep.org; Wed, 01 Aug 2001 13:39:24 +0100 Received: from relay.dera.gov.uk ([192.5.29.49]) by post.thorcom.com with smtp (Exim 3.16 #2) id 15RvHW-0008Km-00 for rsgb_lf_group@blacksheep.org; Wed, 01 Aug 2001 13:39:22 +0100 Content-Transfer-Encoding: 8bit Received: (qmail 21344 invoked from network); 1 Aug 2001 13:36:34 +0100 Received: from trtnmail.dera.gov.uk (146.80.9.56) by relay.dera.gov.uk with SMTP; 1 Aug 2001 13:36:34 +0100 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 25338 invoked from network); 1 Aug 2001 13:40:44 +0100 Received: (ofmipd 192.5.29.90); 1 Aug 2001 12:40:22 -0000 Received: by bob.dera.gov.uk; (8.8.8/1.3/10May95) id NAA25271; Wed, 1 Aug 2001 13:44:34 +0100 (BST) X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Received: (qmail 26606 invoked from network); 1 Aug 2001 13:30:00 -0000 Received: from gauntlet.mail.dera.gov.uk (172.16.9.10) by baton.dera.gov.uk with SMTP; 1 Aug 2001 13:30:00 -0000 Received: by gauntlet.mail.dera.gov.uk; id NAA16913; Wed, 1 Aug 2001 13:17:36 GMT Received: from unknown(10.71.64.31) by gauntlet.mail.dera.gov.uk via smap (3.2) id xma016900; Wed, 1 Aug 01 13:17:18 GMT Received: from mailex.dera.gov.uk (unverified) by mailguard.dera.gov.uk (Content Technologies SMTPRS 4.1.5) with SMTP id for ; Wed, 1 Aug 2001 13:38:17 +0100 Received: (qmail 21739 invoked from network); 1 Aug 2001 12:26:50 +0100 Date: 1 Aug 2001 13:36:53 +0100 Message-ID: <7D653C9C42F5D411A27C00508BF8803D55C576@pdw-mail-r1.dstl.gov.uk> From: "Andrew Talbot" To: rsgb_lf_group@blacksheep.org X-5Received: from softdnserror (HELO cchecker.dstl.gov.uk) (192.168.248.52) by mailex.dstl.gov.uk with SMTP; 1 Aug 2001 11:26:50 -0000 X-4Received: from FRN-MAIL-R3.dstl.gov.uk (unverified) by cchecker.dstl.gov.uk (Content Technologies SMTPRS 4.1.2) with ESMTP id for ; Wed, 1 Aug 2001 12:26:39 +0100 X-3Received: by FRN-MAIL-R3 with Internet Mail Service (5.5.2650.21)id ; Wed, 1 Aug 2001 13:36:51 +0100 Subject: LF: RE: Re: SV: Re: SV: LF Receivers MIME-Version: 1.0 X-Mailer: Internet Mail Service (5.5.2650.21) Content-Type: text/plain; charset=iso-8859-1; format=flowed Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: The PTC crystal heater may be one of the reasons for your sucess in pulling it so far. Most crystals are designed for nominal 20 deg operation, and if you heat them up the frequency drops. These crystal heaters are particularly useful for /P microwave operators as they allow < 1ppm from a cheap and simple oven. But the crystal must be cut for operation at 50 deg or whatever temperature is chosen. Many of us initially tried the 40 deg heaters on normal 20 deg crystals and found worse stability than not using any heater when exposed to the wide variations out in the field. What happened is that the rise in operating temperature moved the location on the freq / temp response away from the point of inflexion, where it is not too sensitive to a few degrees of variation, (it has a cubic law) onto a steeper part of the curve so the whole arrangement was now a lot more sensitive to external temperature effects. However, using one of these heaters indoors, where temperature is already quite constant does not show the effect so much and does give improved stability over a few degrees variation. Andy G4JNT > -----Original Message----- > From: John Andrews [mailto:w1tag@charter.net] > Sent: 2001-08-01 12:40 > To: rsgb_lf_group@blacksheep.org > Subject: LF: Re: SV: Re: SV: LF Receivers > > > Johan, > > >Do you have any circuit suggestion for a suitable "rock bender"? > > I just used a simple Pierce FET oscillator, followed by an > LM6321 buffer, > and it worked. I have an air variable trimmer for rough setting, and a > tuning diode run by a 10 turn pot. I did glue a PTC thermistor to the > crystal to help with temperature. I'll know more about > stability in a couple > of weeks. > > John Andrews, W1TAG > > -- The Information contained in this E-Mail and any subsequent correspondence is private and is intended solely for the intended recipient(s). For those other than the recipient any disclosure, copying, distribution, or any action taken or omitted to be taken in reliance on such information is prohibited and may be unlawful.