Return-Path: Received: from rly-mh02.mx.aol.com (rly-mh02.mail.aol.com [172.21.166.138]) by air-mh04.mail.aol.com (v121_r4.6) with ESMTP id MAILINMH043-bba4948231c226; Tue, 16 Dec 2008 16:52:49 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-mh02.mx.aol.com (v121_r4.4) with ESMTP id MAILRELAYINMH022-bba4948231c226; Tue, 16 Dec 2008 16:52:31 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LChpu-0005Kv-8e for rs_out_1@blacksheep.org; Tue, 16 Dec 2008 21:52:14 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LChpt-0005Km-O5 for rsgb_lf_group@blacksheep.org; Tue, 16 Dec 2008 21:52:13 +0000 Received: from pne-smtpout1-sn1.fre.skanova.net ([81.228.11.98]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LChps-0007lh-Li for rsgb_lf_group@blacksheep.org; Tue, 16 Dec 2008 21:52:13 +0000 Received: from [127.0.0.1] (62.20.250.99) by pne-smtpout1-sn1.fre.skanova.net (7.3.129) (authenticated as u33233109) id 47A9795005319786 for rsgb_lf_group@blacksheep.org; Tue, 16 Dec 2008 22:52:06 +0100 Message-ID: <49482306.2010007@telia.com> Date: Tue, 16 Dec 2008 22:52:06 +0100 From: "Johan H. Bodin" User-Agent: Thunderbird 2.0.0.18 (Windows/20081105) MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <000b01c95ed5$a2cda180$4201a8c0@home> <017701c95fb3$2e39e2a0$6401a8c0@asus> <20081216211341.k5n9k2c6zg8woooo@webmail4.kuleuven.be> In-Reply-To: <20081216211341.k5n9k2c6zg8woooo@webmail4.kuleuven.be> X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: RE: Re: whisper Content-Type: text/plain; charset=ISO-8859-1 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=0.0 required=5.0 tests=none 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-IP: 193.82.116.20 X-Mailer: Unknown (No Version) Rik Strobbe wrote: > if I got it right WSPR is a 4-FSK mode and does not require linear > amplification. Correct, and, according to Joe K1JT, a "FSK tone accuracy" of 0.1Hz or so is enough to not compromise performance too much (FSK tone spacing is ~1.46Hz). The QRP minded can easily achieve this accuracy with a simple VCXO which Peter DL6NL has shown with his PC-less WSPR beacon which has been on the air 7*24h for half a year on 30 meters. He is using a PIC microcontroller together with a QRPp TX of his own design. A simple PIC based WSPR beacon controller for VCXO or AD9850 DDS can be found here: http://web.telia.com/~u33233109/mept_jt/mjb002.zip The current version transmits WSPR modulation only but the firmware can easily be modified to insert traditional CW IDs at regular intervals to enable reception at such remote places as a misspelled Scraborough. 73 Johan SM6LKM