Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mk01.r1000.mx.aol.com (Internet Inbound) with ESMTP id 6A5F9380000B1; Wed, 3 Aug 2011 16:08:36 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1QohjG-0001fF-Fw for rs_out_1@blacksheep.org; Wed, 03 Aug 2011 21:07:46 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QohjF-0001f6-Vr for rsgb_lf_group@blacksheep.org; Wed, 03 Aug 2011 21:07:45 +0100 Received: from out1.ip01ir2.opaltelecom.net ([62.24.128.237]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QohjD-0006rw-HI for rsgb_lf_group@blacksheep.org; Wed, 03 Aug 2011 21:07:45 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AusAACeqOU5Ok8E3/2dsb2JhbABCgk2RPIN+j1l4gTsFAQEFCAEBA0kCLAEBAwUCAQMRBAEBCiUUAQQaBhYIBhMKAQICAQGHXcEhhkIEglCEW5w1 X-IronPort-AV: E=Sophos;i="4.67,312,1309734000"; d="scan'208,217";a="361279720" Received: from host-78-147-193-55.as13285.net (HELO xphd97xgq27nyf) ([78.147.193.55]) by out1.ip01ir2.opaltelecom.net with SMTP; 03 Aug 2011 21:07:37 +0100 Message-ID: <004a01cc5218$fd9a91c0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: Date: Wed, 3 Aug 2011 21:07:36 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2600.0000 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2600.0000 X-Spam-Score: 0.0 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001 Subject: LF: Re: RE: Antennas Content-Type: multipart/alternative; boundary="----=_NextPart_000_0047_01CC5221.5EFD2AB0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.8 required=5.0 tests=HTML_30_40,HTML_MESSAGE 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-global-disposition: G X-AOL-SCOLL-SCORE: 0:2:443327680:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d61854e39aac45cdf X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none This is a multi-part message in MIME format. ------=_NextPart_000_0047_01CC5221.5EFD2AB0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable SNR is unimportant if you cannot hear the signal in the first place = !!!!!!! If one is plagued with environmental noise and poor signal quality on = LF/MF then maybe this is not the band for You. Try another hobby G3KEV ----- Original Message -----=20 From: Rik Strobbe=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Wednesday, August 03, 2011 8:38 PM Subject: LF: RE: Antennas Hi Chris, the quality of the received signal it determined by it's SNR. So if = you have an antenna where QRM/QRN are at a higher level than the RX = noise it makes no sense to get a larger antenna (=3D produce more signal = and noise). As QRM / QRN on 137kHz and even on 500kHz is rather high even with a = small antenna you will get more QRM / QRN and it will perform as well as = a big antenna. So it seems absolutely normal to me that a small whip will performp as = well as a big wire antenna (for RX !). More important that size might be other properties such as directivity = (eg with a loop you can null out a QSM source). I do use my "big" TX antenna for RX, but do need to attenuate the = signal by at least 20dB to avoid RX overloading. 73, Rik ON7YD - OR7T=20 -------------------------------------------------------------------------= ----- Van: owner-rsgb_lf_group@blacksheep.org = [owner-rsgb_lf_group@blacksheep.org] namens Chris = [c.ashby435@btinternet.com] Verzonden: woensdag 3 augustus 2011 20:08 Aan: RSGB LF Group Onderwerp: LF: Antennas Hi Mal and LF, Well, all I can say is that here the signal to noise ratio on RX is = better on my PA0RDT than it is on my long wire (inverted 'L'). I have = always thought this a bit strange, quite often weak signals that cannot = be seen on the wire are perfectly copied on the PA0RDT. This applies = from 136kHz to 3.8MHz. I cannot see what else it can be other than local = noise/QRM level. 80m is another prime example where the noise has = gradually got worse over the years here. Vy 73, Chris, G4AYT, Whitstable, Kent. ------=_NextPart_000_0047_01CC5221.5EFD2AB0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
SNR is unimportant if you cannot hear the signal = in the=20 first place !!!!!!!
If one is plagued with environmental noise and = poor signal=20 quality on LF/MF then maybe this is not the band for You.
Try another hobby
G3KEV
 
----- Original Message -----
From:=20 Rik Strobbe
Sent: Wednesday, August 03, = 2011 8:38=20 PM
Subject: LF: RE: Antennas

Hi Chris,
 
the quality of the received signal it determined by it's SNR. So = if you=20 have an antenna where QRM/QRN are at a higher level than the RX = noise it=20 makes no sense to get a larger antenna (=3D produce more signal and=20 noise).
As QRM / QRN on 137kHz and even on 500kHz is rather high even = with a=20 small antenna you will get more QRM / QRN and it will perform as well = as a big=20 antenna.
So it seems absolutely normal to me that a small whip will = performp as=20 well as a big wire antenna (for RX !).
More important that size might be other properties such as = directivity=20 (eg with a loop you can null out a QSM source).
 
I do use my "big" TX antenna for RX, but do need to attenuate the = signal=20 by at least 20dB to avoid RX overloading.
 
73, Rik  ON7YD - OR7T 
 
Van:=20 owner-rsgb_lf_group@blacksheep.org = [owner-rsgb_lf_group@blacksheep.org] namens=20 Chris [c.ashby435@btinternet.com]
Verzonden: woensdag 3 = augustus=20 2011 20:08
Aan: RSGB LF Group
Onderwerp: LF:=20 Antennas

Hi Mal and LF,
Well, all I can say is that here the = signal to=20 noise ratio on RX is better on my PA0RDT than it is on my long wire = (inverted=20 'L'). I have always thought this a bit strange, quite often weak = signals that=20 cannot be seen on the wire are perfectly copied on the PA0RDT. This = applies=20 from 136kHz to 3.8MHz. I cannot see what else it can be other than = local=20 noise/QRM level. 80m is another prime example where the noise has = gradually=20 got worse over the years here.
Vy 73,
Chris, G4AYT, Whitstable,=20 Kent.
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