Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-mj03.r1000.mx.aol.com (Internet Inbound) with ESMTP id 0561338000092; Wed, 3 Aug 2011 16:04:16 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Qohea-0001Sv-Ae for rs_out_1@blacksheep.org; Wed, 03 Aug 2011 21:02:56 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1QoheZ-0001Sm-I1 for rsgb_lf_group@blacksheep.org; Wed, 03 Aug 2011 21:02:55 +0100 Received: from out1.ip06ir2.opaltelecom.net ([62.24.128.242]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1QoheX-0006iT-CO for rsgb_lf_group@blacksheep.org; Wed, 03 Aug 2011 21:02:55 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: AusAACqpOU5Ok8E3/2dsb2JhbABClAYDg36PWXiBOwUBAQUIAQEDSQIsAQEDBQIBAxEEAQEKJRQBBBoGFggGEwoBAgIBAYddAsEjhkIEglCEW5U7hno X-IronPort-AV: E=Sophos;i="4.67,312,1309734000"; d="scan'208,217";a="508324326" Received: from host-78-147-193-55.as13285.net (HELO xphd97xgq27nyf) ([78.147.193.55]) by out1.ip06ir2.opaltelecom.net with SMTP; 03 Aug 2011 21:02:45 +0100 Message-ID: <004001cc5218$4fe719e0$0401a8c0@xphd97xgq27nyf> From: "mal hamilton" To: References: Date: Wed, 3 Aug 2011 21:02:45 +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: Re: LF: Antennas Content-Type: multipart/alternative; boundary="----=_NextPart_000_003D_01CC5220.B174BA70" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.5 required=5.0 tests=HTML_20_30,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: 0:2:473310336:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039400c89a64e39a9c06504 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_003D_01CC5220.B174BA70 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Roger In your case from what you say it would be a good idea to move to the = VHF/UHF region, others should consider your advice. Why struggle on LF/MF when you could do better with a lot less power on = the microwave bands.=20 I got a lot of pleasure using satellites for communications since the = OSCAR 6 es OSCAR 10 days. I hold the record on OSCAR 6 for distance, HONGKONG to Melbourne. =20 de Mal/VS6HI/G3KEV ----- Original Message -----=20 From: Roger Lapthorn=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Wednesday, August 03, 2011 8:01 PM Subject: Re: LF: Antennas Mal You may be right about big antennas in a decent, quiet rural location = but the majority of us now live close to modern civilisation with noise = floors that have risen some 20-30dB or more at the lower end of the = spectrum in recent years.=20 Top Band is almost unusable here and 80m not a lot better. I am = surprisingly lucky on 500kHz and 136kHz where I seem to be able to hold = my own on receive with my loop antenna in its favoured directions. Many = get very good results with PA0RDT type E-field probe antennas with = careful location and after efforts to minimise noise pick-up. In the end = S/N is all that matters so having a large antenna which increases both = wanted signal and noise has no benefit as long as the S/N is as good as = it can be. With more and more difficult noise environments in most urban and = semi-urban locations I can see many people giving up amateur radio below = 432MHz. I am tempted more and more to move up to the UHF and microwave = region to get my next challenges and I live on the edge of a village = where the noise must be far less of an issue than for my city friends. A little more understanding of the plight of many LFers in busy cities = and some encouraging words and ideas would be good Mal. 73s Roger G3XBM On 3 August 2011 19:08, Chris wrote: 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. --=20 http://g3xbm-qrp.blogspot.com/ http://www.g3xbm.co.uk http://www.youtube.com/user/g3xbm https://sites.google.com/site/sub9khz/ ------=_NextPart_000_003D_01CC5220.B174BA70 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Roger
In your case from what you say it would be a = good=20 idea to move to the VHF/UHF region, others should consider your=20 advice.
Why struggle on LF/MF when you could do = better with a=20 lot less power on the microwave bands.
I got a lot of pleasure using satellites = for=20 communications since the OSCAR 6 es OSCAR 10 days.
I hold the record on OSCAR 6 for=20 distance, HONGKONG to Melbourne.  
 
de Mal/VS6HI/G3KEV
 
----- Original Message -----
From:=20 Roger=20 Lapthorn
Sent: Wednesday, August 03, = 2011 8:01=20 PM
Subject: Re: LF: Antennas

Mal

You may be right about big antennas in a = decent,=20 quiet rural location but the majority of us now live close to modern=20 civilisation with noise floors that have risen some 20-30dB or more at = the=20 lower end of the spectrum in recent years.

Top Band is almost = unusable=20 here and 80m not a lot better. I am surprisingly lucky on 500kHz and = 136kHz=20 where I seem to be able to hold my own on receive with my loop antenna = in its=20 favoured directions. Many get very good results with PA0RDT type = E-field probe=20 antennas with careful location and after efforts to minimise noise = pick-up. In=20 the end S/N is all that matters so having a large antenna which = increases both=20 wanted signal and noise has no benefit as long as the S/N is as = good as=20 it can be.

With more and more difficult noise environments in = most=20 urban and semi-urban locations I can see many people giving up amateur = radio=20 below 432MHz.  I am tempted more and more to move up to the UHF = and=20 microwave region to get my next challenges and I live on the edge of a = village=20 where the noise must be far less of an issue than for my city=20 friends.

A little more understanding of the plight of many = LFers in=20 busy cities and some encouraging words and ideas would be good=20 Mal.

73s
Roger G3XBM



On 3 August 2011 19:08, Chris <c.ashby435@btinternet.com&g= t;=20 wrote:
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=20 (inverted 'L'). I have always thought this a bit strange, quite = often weak=20 signals that cannot be seen on the wire are perfectly copied on the = PA0RDT.=20 This applies from 136kHz to 3.8MHz. I cannot see what else it can be = other=20 than local noise/QRM level. 80m is another prime example where the = noise has=20 gradually got worse over the years here.
Vy 73,
Chris, G4AYT, Whitstable,=20 Kent.



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http://www.g3xbm.co.uk
http://www.youtube.com/user/g3xbm
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