Envelope-to: dave@picks.force9.co.uk Delivery-date: Thu, 26 Jan 2006 17:58:45 +0000 Received: by ptb-mxcore02.plus.net with spam-scanned (PlusNet MXCore v2.00) id 1F2BOO-0005bx-SO for dave@picks.force9.co.uk; Thu, 26 Jan 2006 17:58:45 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore02.plus.net with esmtp (PlusNet MXCore v2.00) id 1F2BOO-0005ZP-Fx for dave@picks.force9.co.uk; Thu, 26 Jan 2006 17:58:44 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1F2BNX-0001Yg-Fs for rs_out_1@blacksheep.org; Thu, 26 Jan 2006 17:57:51 +0000 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1F2BNX-0001YX-2w for rsgb_lf_group@blacksheep.org; Thu, 26 Jan 2006 17:57:51 +0000 Received: from mout1.freenet.de ([194.97.50.132]) by relay1.thorcom.net with esmtp (Exim 4.51) id 1F2Cex-0003pd-36 for rsgb_lf_group@blacksheep.org; Thu, 26 Jan 2006 19:20:11 +0000 Received: from [194.97.50.138] (helo=mx0.freenet.de) by mout1.freenet.de with esmtpa (Exim 4.61) (envelope-from ) id 1F2BNF-0008I5-Ml for rsgb_lf_group@blacksheep.org; Thu, 26 Jan 2006 18:57:33 +0100 Received: from p54868d67.dip0.t-ipconnect.de ([84.134.141.103] helo=[192.168.0.200]) by mx0.freenet.de with esmtpsa (ID dl4yhf@freenet.de) (TLSv1:AES256-SHA:256) (Exim 4.61 #21) id 1F2BNF-0007wv-Ax for rsgb_lf_group@blacksheep.org; Thu, 26 Jan 2006 18:57:33 +0100 Message-ID: <43D90DB2.40205@freenet.de> Date: Thu, 26 Jan 2006 17:58:10 +0000 From: Wolf DL4YHF User-Agent: Mozilla Thunderbird 0.9 (Windows/20041103) X-Accept-Language: de-DE, de, en-us, en MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: In-Reply-To: Subject: Re: LF: RE: TA 26 JAN 06 XKO Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 8bit 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-PN-SpamFiltered: by PlusNet MXCore (v2.00) Hi Roelof, Gary and others, Gary wrote: >On the top menu bar click > >"View/Windows" then "Spectrum Lab components" & you will get a block >diagram, look for box with ? in it on a connection between L4 & L5 (next to >a green triangle), click this box & point at "Automatic Gain Control" at the >bottom of the list, choosing/setting different values may help the >situation. > >Wolf said this is not a visual gain control like those in Argo & Spectran so >may only have a minimal effect, tried it & believe it did help. The problem >with visual AGC is that it not only reduces the level of visual noise on the >display it also reduces the displayed signal. > > > Thanks for the explanation Gary, it is correct. The downside with the AGC ("visible" or not) is, you don't notice what causes the signal to get weaker on the screen : Is it, because the signal voltage drops, or because the broadband noise level increases ? Without an AGC, you can clearly see the screen getting lighter. And if the (wanted) signal gets darker, you know its voltage drops. For propagation analysis, you want to observe the "absolute" voltage, so better switch the AGC off (this applies to all kinds of AGC's, hard- or software). Furthermore, if you want to plot the field strength in a graph (like CT1DRP and some others in this group do), the AGC *must* be turned off, otherwise the "dBuV / meter" readings get useless. Best regards, Wolf DL4YHF .