X-GM-THRID: 1234647085444953809 X-Gmail-Labels: rsgb lf Delivered-To: daveyxm@gmail.com Received: by 10.35.22.8 with SMTP id z8cs304604pyi; Wed, 25 Apr 2007 05:38:01 -0700 (PDT) Received: by 10.67.76.16 with SMTP id d16mr1358880ugl.1177504681155; Wed, 25 Apr 2007 05:38:01 -0700 (PDT) Return-Path: Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by mx.google.com with ESMTP id 59si3198350ugf.2007.04.25.05.37.58; Wed, 25 Apr 2007 05:38:01 -0700 (PDT) Received-SPF: neutral (google.com: 193.82.116.20 is neither permitted nor denied by best guess record for domain of owner-rsgb_lf_group@blacksheep.org) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1HgghG-0000aG-VY for rs_out_1@blacksheep.org; Wed, 25 Apr 2007 13:34:10 +0100 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1HgghG-0000a6-Bm for rsgb_lf_group@blacksheep.org; Wed, 25 Apr 2007 13:34:10 +0100 Received: from anchor-post-30.mail.demon.net ([194.217.242.88]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1HgghE-0007kb-Uo for rsgb_lf_group@blacksheep.org; Wed, 25 Apr 2007 13:34:10 +0100 Received: from pr-webmail-2.demon.net ([194.159.244.50]) by anchor-post-30.mail.demon.net with esmtp (Exim 4.42) id 1HgghE-000Bi9-0V for rsgb_lf_group@blacksheep.org; Wed, 25 Apr 2007 12:34:08 +0000 Received: from localhost ([127.0.0.1] helo=web.mail.demon.net) by pr-webmail-2.demon.net with smtp (Exim 4.42) id 1HgghD-00024n-VE for rsgb_lf_group@blacksheep.org; Wed, 25 Apr 2007 13:34:08 +0100 Received: from g3xaq.demon.co.uk ([168.224.1.14]) by web.mail.demon.net with http; Wed, 25 Apr 2007 13:34:07 +0100 From: alan@g3xaq.demon.co.uk To: rsgb_lf_group@blacksheep.org In-Reply-To: Date: Wed, 25 Apr 2007 13:34:07 +0100 User-Agent: Demon-WebMail/2.0 MIME-Version: 1.0 Message-Id: X-Spam-Score: 0.8 (/) X-Spam-Report: autolearn=disabled,MAILTO_TO_SPAM_ADDR=0.276,NO_REAL_NAME=0.55 Subject: Re: LF: [ 500] EASY START - ceramic resonators et al Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: * X-Spam-Status: No, hits=1.3 required=5.0 tests=MAILTO_TO_SPAM_ADDR, NO_REAL_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 Status: O X-Status: X-Keywords: X-UID: 1911 Dave, Thanks for saving me the effort of doing the testing on ceramic resonators! I see Rapid also stock these, and the 11.0592 xtals too. I've got my NoV application ready to post tonight and I retire on Monday, so hopefully I can turn all this blathering into results within a couple of weeks! 73, Alan ganymede444@btopenworld.com wrote: > Hi Alan, Alan and LF. > > I've done a few tests with trying to "pull" crystals and resonators up into > the 501-504 kHz band. I used a single NPN transistor in a Colpits > configuration with a 3 - 30pf trimmer capacitor in series with the crystal. > > Firstly, I tried a few 1.000 and 2.000 MHz HC6u crystals, available from RS > Components. These would only move a few tens of Hz maximum, before they > stopped. > > Secondly, I tried ten 500kHz resonators, type Murata 500 CSB. These are > little yellow plastic cuboids approx 10 x 8 x 4 mm with two legs at the > bottom. These all came out low, typically in the 498-499 kHz range, and > couldn't be pulled much higher before they died. > > Thirdly, I tried some 1 MHz resonators, type Murata 1000J. These are even > smaller blue plastic cuboids approx 7 x 5 x 2mm also with two legs on the > bottom. These were much more amenable to "pulling", and would tune from 989 > to 1011 kHz quite happily (494.5 to 505.5 kHz) The frequency stability seems > quite good, and a hot soldering iron on one of the legs moved the frequency > about 200 Hz, coming back on frequency as it cooled down. You would need to > be careful using one of these, however, as you could easily slip out of band > if you moved the trimmer too far. > > So one of these 1MHz resonators would seem to be a good source, once divided > by two. You could leave the oscillator running continously for maximum > stability, and key the divider. I might even have a circuit of a divider > using a double triode if anyone wanted to stay with the retro "Valve theme"! > Otherwise a 74LS74 or a CD 4013 will do the trick nicely. > > BTW, RS Components and Farnell sell a 11.0592 MHz crystal, costing the > princely sum of 19 pence, which when divided by 22 will give 502.69 MHz. > (74LS161 followed by 74LS74...no problemo...) > > 73, Dave G3WCB IO91RM > > -----Original Message----- > From: owner-rsgb_lf_group@blacksheep.org > [mailto:owner-rsgb_lf_group@blacksheep.org]On Behalf Of Alan Melia > Sent: 23 April 2007 23:36 > To: rsgb_lf_group@blacksheep.org > Subject: Re: LF: 500 EASY START > > > Hi Alan, there is not a lot of "accumulated wisdom" on 500kHz yet but most > of the 136khz experience seems to work. The best tutorial for aerials at LF > is the pages by Rik Srobbe ON7YD. You will find a lot else there as well. > http://www.qsl.net/on7yd/ and click on "The 136kHz Amateur Band" in the > left-hand bar. > > Low frequency crystals are almost unknown these days. It is so easy to > divide down. Two techniques have been used straight division like Mal > suggests or mixing crystals in the 5 to 6 meg range...pulling one up and the > other down with a 2 gang variable cap. as Dave Sargent recently described. > > Have you though of trying at 50p ceramic resonator !! 500kHz is a stadard > frequency for these and they are fairly "bendable" so may come up into the > band. I think GW3EUP uses one. > > You will find a spreadsheet on my web site (beside a lot of other junk) > which attemmpts to simplify the ERP calculation. > http://www.btinternet.com/~alan.melia/programs.htm > It is an EXCEL sheet and should download OK. > > I hope that helps ...welcome to LF and remember LF=Lotsa Fun !! > > Cheers de Alan G3NYK > > > ----- Original Message ----- > From: Alan Ibbetson > To: > Sent: 23 April 2007 23:03 > Subject: Re: LF: 500 EASY START > > > > Hello everyone, Alan G3XAQ here. I just joined this mailing list. I'm > > preparing my application for a 501KHz NoV, so Mal's note on an easy > > start is very timely. > > > > > > > >