Envelope-to: dave@picks.force9.co.uk Delivery-date: Sat, 28 Jan 2006 17:26:46 +0000 Received: by ptb-mxcore02.plus.net with spam-scanned (PlusNet MXCore v2.00) id 1F2tqY-0002eZ-2m for dave@picks.force9.co.uk; Sat, 28 Jan 2006 17:26:46 +0000 Received: from post.thorcom.com ([193.82.116.20]) by ptb-mxcore02.plus.net with esmtp (PlusNet MXCore v2.00) id 1F2tqX-0002eE-UM for dave@picks.force9.co.uk; Sat, 28 Jan 2006 17:26:46 +0000 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1F2tpc-0007yR-Js for rs_out_1@blacksheep.org; Sat, 28 Jan 2006 17:25:48 +0000 Received: from [193.82.59.130] (helo=relay2.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1F2tpc-0007yI-3r for rsgb_lf_group@blacksheep.org; Sat, 28 Jan 2006 17:25:48 +0000 Received: from smtp805.mail.ukl.yahoo.com ([217.12.12.195]) by relay2.thorcom.net with smtp (Exim 4.51) id 1F2uVY-0007xb-Hs for rsgb_lf_group@blacksheep.org; Sat, 28 Jan 2006 18:09:09 +0000 Received: (qmail 3166 invoked from network); 28 Jan 2006 17:24:46 -0000 Received: from unknown (HELO lark) (alan.melia@btinternet.com@213.122.50.20 with login) by smtp805.mail.ukl.yahoo.com with SMTP; 28 Jan 2006 17:24:45 -0000 Message-ID: <003201c6242f$c1ef8300$67b0fea9@lark> From: "Alan Melia" To: rsgb_lf_group@blacksheep.org References: <016101c61d02$12ceca40$2101a8c0@pcroelof> <002b01c61d54$c510aaa0$20347ad5@w4o8m9> <013401c621bd$c7f33c20$2101a8c0@pcroelof> <000001c621d9$6ee29240$67b0fea9@lark> <000b01c621df$f54a2ae0$2101a8c0@pcroelof> <001101c6240c$0e206790$2101a8c0@pcroelof> Date: Sat, 28 Jan 2006 16:15:52 -0000 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 5.00.2615.200 X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2615.200 Subject: LF: Re: Mini Whip and local noise and height AGL 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, thanks for those measurements. I am guessing that there is some effect from the roof at "zero height" as I would only expect doubling the height to give 6dB. It looks like the "effective height" is measured from the roof in this case. height about 1.5m , multiply by 4 for 12db at 12m is about right. Strange ! However it certainly demonstrates the importance of height with a e-field probe. I think Dave G3YXM found a bit difference when he elevated his a bit more. I suppose it could be the effect of buildings on the wavefront despite the fact that they a much smaller than a wavelength. Thanks and Cheers de Alan G3NYK ----- Original Message ----- From: Roelof Bakker To: Sent: 28 January 2006 13:09 Subject: LF: Re: Re: Re: Re: Re: Mini Whip and local noise > Hello Alan, LF-group, > > In my notebook some more height versus signal level figures were found. > This was a test on my semi-flat roof, starting 1 metre above the roof and 7 > metre from the ground. > > height rel. dB > ================= > 7 m / 23.0 ft 0 dB > 8 m / 26.2 ft + 4 dB > 9 m / 29.5 ft + 6 dB > 10 m / 32.8 ft + 9 dB > 11 m / 36.0 ft + 10.2 dB > 12 m / 39.3 ft + 11.5 dB > > As said before, signal to noise ratio did not change with height. > > Best regards, > > Roelof Bakker, pa0rdt > >