Return-Path: Received: (qmail 12981 invoked from network); 23 Jul 2002 14:19:10 -0000 Received: from marstons.services.quay.plus.net (212.159.14.223) by mailstore with SMTP; 23 Jul 2002 14:19:10 -0000 X-Priority: 3 X-MSMail-Priority: Normal Received: (qmail 105 invoked by uid 10001); 23 Jul 2002 14:22:49 -0000 Received: from post.thorcom.com (193.82.116.70) by marstons.services.quay.plus.net with SMTP; 23 Jul 2002 14:22:49 -0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 X-SQ: A Received: from majordom by post.thorcom.com with local (Exim 3.33 #2) id 17X0Nt-0004wP-00 for rsgb_lf_group-outgoing@blacksheep.org; Tue, 23 Jul 2002 15:11:29 +0100 Received: from cmailenv1.svr.pol.co.uk ([213.218.77.53]) by post.thorcom.com with esmtp (Exim 3.33 #2) id 17X0Ns-0004wK-00 for rsgb_lf_group@blacksheep.org; Tue, 23 Jul 2002 15:11:28 +0100 Received: from [62.21.133.177] (helo=w8k3f0.freeler.nl) by cmailENV1.svr.pol.co.uk with esmtp (Exim 3.35 #1) id 17X0No-0007x0-00; Tue, 23 Jul 2002 14:11:26 +0000 Message-ID: <5.1.0.14.0.20020723160200.009fa8c0@POP3.freeler.nl> X-Sender: FRE0000086604@POP3.freeler.nl X-Mailer: QUALCOMM Windows Eudora Version 5.1 Date: Tue, 23 Jul 2002 16:13:34 +0200 To: "Reg Edwards" , "LF-Group" From: "Dick Rollema" Subject: LF: Re: Calculating ERP from measured field strength In-reply-to: <006a01c230a9$17142e40$1c8901d5@kitchen> References: <5.1.0.14.0.20020720130356.009eb780@POP3.freeler.nl> <5.1.0.14.0.20020721095922.00a05170@POP3.freeler.nl> MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org X-Listname: rsgb_lf_group Sender: Content-transfer-encoding: 8bit To Reg, G4FGQ and the LF-group

Reg, G4FGQ wrote:

Yes, I am aware of that. But I am interested in the extent to which VLF

predicting capability of program GrndWav3 is affected by skywaves. It would
be nice to state confidence limits on predicting error, + or - dB or
something like that.

Any info is better than none. I have no means of making any measurements
myself. So should some very inacurate data turn up it would be of
interest.

I would like to provide this data. But my problem is that in order to do a reliable measurement the signal has to be sufficiently over the local noise level. This means it must be about S6 or more. Signals you would like to be measured do not come up to that level.
But in order to find out whether a signal is affected by sky wave you could monitor the strong commercial stations adjacent to our LF band. When they vary in strength with time that is an indication there is a mix of ground and skywave.

73, Dick, PA0SE