Return-Path: Received: from rly-de12.mx.aol.com (rly-de12.mail.aol.com [172.19.170.148]) by air-de03.mail.aol.com (v126.13) with ESMTP id MAILINDE034-51a4b224d2b2f2; Fri, 11 Dec 2009 08:46:28 -0500 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-de12.mx.aol.com (v125.7) with ESMTP id MAILRELAYINDE121-51a4b224d2b2f2; Fri, 11 Dec 2009 08:46:21 -0500 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1NJ5oQ-0007Sc-HG for rs_out_1@blacksheep.org; Fri, 11 Dec 2009 13:45:38 +0000 Received: from [83.244.159.144] (helo=relay3.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1NJ5oQ-0007ST-3p for rsgb_lf_group@blacksheep.org; Fri, 11 Dec 2009 13:45:38 +0000 Received: from cavuit02.kulnet.kuleuven.be ([134.58.240.44]) by relay3.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1NJ5oO-0000CB-Eo for rsgb_lf_group@blacksheep.org; Fri, 11 Dec 2009 13:45:38 +0000 Received: from smtps02.kuleuven.be (smtpshost02.kulnet.kuleuven.be [134.58.240.75]) by cavuit02.kulnet.kuleuven.be (Postfix) with ESMTP id B217651C00B for ; Fri, 11 Dec 2009 14:45:26 +0100 (CET) Received: from PC_van_Rik.fys.kuleuven.be (dhcp-10-33-85-106.fys.kuleuven.be [10.33.85.106]) by smtps02.kuleuven.be (Postfix) with ESMTP id 9C23EF3862 for ; Fri, 11 Dec 2009 14:45:26 +0100 (CET) X-Mailer: QUALCOMM Windows Eudora Version 7.1.0.9 Date: Fri, 11 Dec 2009 14:45:50 +0100 To: "rsgb_lf_group@blacksheep.org" X-Kuleuven: This mail passed the K.U.Leuven mailcluster From: Rik Strobbe References: <1260444821.6353.65.camel@vaio3rd> Mime-Version: 1.0 Message-Id: <20091211134526.9C23EF3862@smtps02.kuleuven.be> X-KULeuven-Information: Katholieke Universiteit Leuven X-KULeuven-Scanned: Found to be clean X-KULeuven-Envelope-From: rik.strobbe@fys.kuleuven.be X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,none Subject: Re: LF: "Gain" between qrss3 and qrss10? Content-Type: text/plain; charset="us-ascii"; format=flowed 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=TO_ADDRESS_EQ_REAL 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 Stefan, if output power is constant and the noise (at RX) is uniform then the SNR is directly related to the RX bandwidth, what must be at least equal to the useful bandwidth of the TX signal. The required bandwidth for QRSS30 (0.033Hz) is ten times smaller than for QRSS3 (0.33Hz), so QRSS30 should have a 10dB better SNR. QRSS10 (bandwidth 0.1Hz) is about 5dB better tha QRSS3 and 5dB worse than QRSS30. The above also assumes that both RX and TX stability are sufficient. Have a look at http://www.qsl.net/on7yd/136narro.htm Another limit is the "stability" of the ionosphere, causing doppler effect and thus limiting the minimal bandwidth. Most of the time on 137kHz one can go as slow as QRSS120, but at 10MHz QRSS10 is the limit. 73, Rik ON7YD - OR7T At 13:29 11/12/2009, you wrote: >Dear LF, >Does anybody know about the "gain" between QRSS3 and QRSS10 or >QRSS30? I mean, if the noise in both cases is equal, how much can I >reduce my tx pwr when switching from qrss3 to qrss10? Or isn't it >possible to give such a relation? >And: Was there ever a TA QSO in QRSS3? >I am new on the reflector, sri ;-) > >Stefan / DK7FC