Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-ma05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 78BA1380000C4; Tue, 26 Jun 2012 12:11:11 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1SjYKp-0006Jq-NL for rs_out_1@blacksheep.org; Tue, 26 Jun 2012 17:09:47 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1SjYKp-0006Jh-5z for rsgb_lf_group@blacksheep.org; Tue, 26 Jun 2012 17:09:47 +0100 Received: from smtpout3.wanadoo.co.uk ([80.12.242.59] helo=smtpout.wanadoo.co.uk) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1SjYKn-00082v-HP for rsgb_lf_group@blacksheep.org; Tue, 26 Jun 2012 17:09:46 +0100 Received: from AGB ([2.26.9.125]) by mwinf5d36 with ME id T49h1j00R2hrnui0349hqb; Tue, 26 Jun 2012 18:09:44 +0200 Message-ID: <172D1CB5F32F43A790DBC99A73F73D59@AGB> From: "Graham" To: References: <002801cd536e$76b08400$0401a8c0@xphd97xgq27nyf> In-Reply-To: <002801cd536e$76b08400$0401a8c0@xphd97xgq27nyf> Date: Tue, 26 Jun 2012 17:09:41 +0100 MIME-Version: 1.0 X-Priority: 3 X-MSMail-Priority: Normal Importance: Normal X-Mailer: Microsoft Windows Live Mail 14.0.8117.416 X-MimeOLE: Produced By Microsoft MimeOLE V14.0.8117.416 X-Antivirus: avast! (VPS 120626-0, 26/06/2012), Outbound message X-Antivirus-Status: Clean X-Spam-Score: 0.0 (/) X-Spam-Report: Spam detection software, running on the system "relay1.thorcom.net", has identified this incoming email as possible spam. The original message has been attached to this so you can view it (if it isn't spam) or label similar future email. If you have any questions, see the administrator of that system for details. Content preview: Steady on Mal ! this is getting technical !" Your right , FM has a cut off point , where demodulation fails and also a capture effect , where the stronger of 2 signals will acquire and hold the demodulator ..always fun on 2 mtrs when a mobile suddenly takes the channel [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [80.12.242.59 listed in list.dnswl.org] 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: 34d483c57c7a6bf26c25db3c8765d5fc Subject: Re: LF: A/G FREQS Content-Type: multipart/alternative; boundary="----=_NextPart_000_0038_01CD53BE.79C61A10" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.9 required=5.0 tests=HTML_30_40,HTML_MESSAGE, MISSING_OUTLOOK_NAME 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: 0:2:423539296:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1d600d4fe9df1d6705 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_0038_01CD53BE.79C61A10 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Steady on Mal ! this is getting technical !" Your right , FM has a cut off point , where demodulation fails = and also a capture effect , where the stronger of 2 signals will = acquire and hold the demodulator ..always fun on 2 mtrs when a = mobile suddenly takes the channel=20 Am has no cut off point , but gradual degradation until the = recovered audio is no longer usable ......eg, mcw would readable = much lower than AM speech=20 I think much over 250/300 MHz its actually not possible to = produce AM , could be wrong , but there is a limit , may be by = high level modulation falls over , dont see why could not be = via transverting .......=20 G.. From: mal hamilton=20 Sent: Tuesday, June 26, 2012 8:36 AM To: rsgb=20 Subject: LF: A/G FREQS As stated Air/Ground vhf/uhf is AM and simplex working. I have also = noticed a well modulated AM transmitter is more potent than a FM = transmitter when working at max range. On AM the RX bandwidth can be = opened up to receive several stations simultaneously then select the one = of interest by closing down the selectivity, the same applies on CW. On = FM if you tried this the transmission would fall into a black hole, in = other words the FM rx has to be tailored to the exact bandwidth of the = transmission (same deviation value) g3kev ------=_NextPart_000_0038_01CD53BE.79C61A10 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Steady on Mal !   this  is getting  = technical =20 !"
 
Your  right  , FM has a  cut off  point  , = where  demodulation fails  and  also  a  = capture =20 effect , where the  stronger of  2 signals  will =20 acquire  and  hold the  demodulator ..always  =20 fun  on 2  mtrs   when a  mobile  = suddenly =20 takes  the  channel
 
Am  has no  cut off  point , but  gradual  = degradation  until the  recovered  audio  is = no  longer=20 usable  ......eg,  mcw  would  readable  = much =20 lower  than  AM speech
 
I think  much over  250/300 MHz   its =20 actually  not  possible to  produce  AM  , = could=20 be  wrong  , but  there is a  limit  , = may  =20 be  by  high  level  modulation falls over , = dont =20 see  why  could  not  be  via  = transverting =20 .......
 
G..
From: mal hamilton
Sent: Tuesday, June 26, 2012 8:36 AM
To: rsgb
Subject: LF: A/G FREQS

As stated Air/Ground vhf/uhf is AM and=20 simplex working.  I have also noticed a well modulated AM = transmitter=20 is more potent than a FM transmitter when working at max range. On AM = the RX=20 bandwidth can be opened up to receive several stations simultaneously = then=20 select the one of interest by closing down the selectivity, the same = applies on=20 CW.  On FM if you tried this the transmission would fall into = a black=20 hole, in other words the FM rx has to be tailored to the=20 exact bandwidth of the transmission (same deviation = value)
g3kev
 
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