Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dk02.r1000.mx.aol.com (Internet Inbound) with ESMTP id 094803800008A; Sat, 20 Aug 2011 17:29:57 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Qut5x-0003g0-QH for rs_out_1@blacksheep.org; Sat, 20 Aug 2011 22:28:45 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Qut5x-0003fr-CP for rsgb_lf_group@blacksheep.org; Sat, 20 Aug 2011 22:28:45 +0100 Received: from smtp5.freeserve.com ([193.252.22.151] helo=smtp6.freeserve.com) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1Qut5u-000857-UV for rsgb_lf_group@blacksheep.org; Sat, 20 Aug 2011 22:28:45 +0100 Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3534.me.freeserve.com (SMTP Server) with ESMTP id F0C551C00082 for ; Sat, 20 Aug 2011 23:28:36 +0200 (CEST) Received: from me-wanadoo.net (localhost [127.0.0.1]) by mwinf3534.me.freeserve.com (SMTP Server) with ESMTP id E29111C00086 for ; Sat, 20 Aug 2011 23:28:36 +0200 (CEST) Received: from AGB (unknown [2.26.46.111]) by mwinf3534.me.freeserve.com (SMTP Server) with SMTP id 7AC0B1C00082 for ; Sat, 20 Aug 2011 23:28:34 +0200 (CEST) X-ME-UUID: 20110820212834502.7AC0B1C00082@mwinf3534.me.freeserve.com Message-ID: From: "Graham" To: Date: Sat, 20 Aug 2011 22:28:33 +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 110820-1, 20/08/2011), Outbound message X-Antivirus-Status: Clean X-Spam-Score: 0.2 (/) X-Spam-Report: autolearn=disabled,HTML_MESSAGE=0.001,RCVD_ILLEGAL_IP=0.234 Subject: LF: Minimum carrier detect level -140 dBm is that good ? Content-Type: multipart/alternative; boundary="----=_NextPart_000_004D_01CC5F88.7F2F77B0" 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: 0:2:284641984:93952408 X-AOL-SCOLL-URL_COUNT: 0 x-aol-sid: 3039ac1db4064e502755725d 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_004D_01CC5F88.7F2F77B0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Minimum carrier detect level -140 dBm is that good ? Run into a odd problem on 500Khz , neither the RA6790 (with LF front = end / no rf pre amp) or the RA1778 will show a carrier on 504 = Khz , that the Skanti R5003 , shows at 10/20 dB over the noise level = using 'spec-lab' as the indicator, R5003 , has no pre-amp , direct to = first mixer. same as the RA 6790 Using the sig-gen and 60 dB atten , the RA1778 minimum trace level = is -150 / -155 dBm (has rf-pre amp) , The 6790, round -140 / -145.. = removing the rf cable and fitting 50 ohm load to gen o/p with = atten , removes the trace from the rx, so assume its not leakage=20 As these levels are well below the ambient noise levels, it not a = sensitivity problem .??. adding a stepped attenuator to the Ae = signal path , makes no difference, other than to alter the noise = level.. The 500 khz feed is from the atu and the vswr round 1:1.2 on tx = .The R5003 is the same lay-out , 40 meg 1st IF > 1.4 second (rx = section of the TRP5000)=20 Any ideas or suggestions as to 'how' to solve the problem .. wide band noise causing the roofing filter to ring may be? Tnx -Graham ------=_NextPart_000_004D_01CC5F88.7F2F77B0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Minimum carrier  detect  = level =20 -140 dBm   is that  good ?
 
Run into  a odd  = problem  on 500Khz=20 , neither the RA6790 (with LF front end  / no  rf  pre = amp) =20 or the  RA1778   will  show a  carrier on 504 = Khz ,=20 that the  Skanti R5003 , shows at 10/20 dB over the  = noise =20 level  using  'spec-lab' as the indicator, R5003 , has  = no =20 pre-amp , direct to  first mixer. same  as the RA=20 6790
 
Using the  sig-gen  and  = 60 dB =20 atten , the  RA1778 minimum  trace level  is  -150 / = -155=20 dBm (has  rf-pre amp) , The  6790, round  -140 / -145.. = removing=20 the  rf  cable  and fitting  50  ohm load = to  gen=20 o/p with  atten , removes the  trace  from the  rx, = so =20 assume its  not  leakage
 
As  these  levels  = are  well=20 below the  ambient  noise  levels, it not a =20 sensitivity  problem .??. adding a  stepped attenuator  = to=20 the  Ae  signal  path , makes  no  difference, = other=20 than to  alter the  noise  level..
 
The   500  khz feed = is  from=20 the  atu  and the  vswr round 1:1.2 on tx .The  = R5003 =20 is the  same  lay-out , 40 meg 1st IF > 1.4 second (rx=20 section  of the  TRP5000)
 
Any  ideas  or  = suggestions  as=20 to  'how'  to  solve  the  problem = ..

wide band  noise  causing = the =20 roofing filter to  ring may  be?
 
Tnx -Graham

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