Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dl05.r1000.mx.aol.com (Internet Inbound) with ESMTP id 66079380000A1; Sat, 13 Oct 2012 15:54:29 -0400 (EDT) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1TN7m5-0004lN-PU for rs_out_1@blacksheep.org; Sat, 13 Oct 2012 20:53:29 +0100 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1TN7m5-0004lE-93 for rsgb_lf_group@blacksheep.org; Sat, 13 Oct 2012 20:53:29 +0100 Received: from out1.ip02ir2.opaltelecom.net ([62.24.128.238]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1TN7m2-0000zL-9U for rsgb_lf_group@blacksheep.org; Sat, 13 Oct 2012 20:53:28 +0100 X-IronPort-Anti-Spam-Filtered: true X-IronPort-Anti-Spam-Result: ArMBAM/FeVACZMIJ/2dsb2JhbAANNgG8EYcFAQEBAQM4UQsJDwkQAQETDwJGEwgBAYgLqGyTC4tZCoMfBAGDDwOVbIEVkgk X-IronPort-AV: E=Sophos;i="4.80,580,1344207600"; d="scan'208";a="406156695" Received: from host-2-100-194-9.as13285.net (HELO [192.168.2.3]) ([2.100.194.9]) by out1.ip02ir2.opaltelecom.net with ESMTP; 13 Oct 2012 20:53:24 +0100 Message-ID: <5079C6B5.20104@psk31.plus.com> Date: Sat, 13 Oct 2012 20:53:25 +0100 From: g3zjo User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:11.0) Gecko/20120327 Thunderbird/11.0.1 MIME-Version: 1.0 To: rsgb_lf_group@blacksheep.org References: <50782029.2030005@psk31.plus.com> <507947F2.6080809@psk31.plus.com> <50795F14.1030207@iup.uni-heidelberg.de> <50797274.3050401@psk31.plus.com> In-Reply-To: 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: Hi Alan Thanks for your interest and commiserations. On 13/10/2012 19:24, Alan Melia wrote: > Hi Eddie my commisserations on you interference, but can I refer you > to the regulations and in particular the "conditions of your (TV) > licence" "You must not cause undue interference to any other radio > television reception with your TV eqipment" > Note it does not say "broadcast". Yes but I think that the interference report form does not cover Amateur Radio and it is an unprotected service although Ofcom does deal with cases of interference due to faults. > It is interesting you have interference at 500kHz but not 472kHz. This > almost suggests an older CRT system with 15.625kHz line scan coils. > Plasma interference is usualy from one of the PSUs and is radiated by > the braid of the aerial. A TV braid breaker will often cure this. No way is this older CRT stuff, I know of 3 Panasonic Plasma TV's locally and get interference from them all the worse one, (closest) is through the lounge wall. Whereas the PSU' may radiate via the mains lead or antenna feeder Panasonic are well aware of that and have gone to great lengths with huge chunks of ferrite. The main radiation from Plasma TV's is directly via the screen, the plasma discharge, and spreads from LF to UHF, scan rates probably give rise to concentrated bands of interference which can be noticed when tuning the bands or a short wave portable RX, I assume this provides the 472KHz dip. It is really bad at 136 KHz see this picture from my gallery of filth. http://i221.photobucket.com/albums/dd243/radiotalk/zjo_grab600.jpg I did try braid breakers on the main offender, mains and antenna feeder, there was no change what so ever. The interference in the SW BC Bands is also imposed on my telephone line and those in the street right up to the nearest BT cabinet. Unfortunately BC stations can still be heard on a SW 'tranny' providing you are not too close to the source TV, within 10ft through a brick wall, so I cant claim BC interference. > > > If you are on good terms with your neighbour it might be worth drawing > their [...] Content analysis details: (0.0 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- X-Scan-Signature: 8556389a5ea14fbbf9b9d801ab70c592 Subject: Re: LF: EMI... Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: X-Spam-Status: No, hits=0.0 required=5.0 tests=none 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-sid: 3039ac1d4ad35079c6f4671b X-AOL-IP: 195.171.43.25 X-AOL-SPF: domain : blacksheep.org SPF : none Hi Alan Thanks for your interest and commiserations. On 13/10/2012 19:24, Alan Melia wrote: > Hi Eddie my commisserations on you interference, but can I refer you > to the regulations and in particular the "conditions of your (TV) > licence" "You must not cause undue interference to any other radio > television reception with your TV eqipment" > Note it does not say "broadcast". Yes but I think that the interference report form does not cover Amateur Radio and it is an unprotected service although Ofcom does deal with cases of interference due to faults. > It is interesting you have interference at 500kHz but not 472kHz. This > almost suggests an older CRT system with 15.625kHz line scan coils. > Plasma interference is usualy from one of the PSUs and is radiated by > the braid of the aerial. A TV braid breaker will often cure this. No way is this older CRT stuff, I know of 3 Panasonic Plasma TV's locally and get interference from them all the worse one, (closest) is through the lounge wall. Whereas the PSU' may radiate via the mains lead or antenna feeder Panasonic are well aware of that and have gone to great lengths with huge chunks of ferrite. The main radiation from Plasma TV's is directly via the screen, the plasma discharge, and spreads from LF to UHF, scan rates probably give rise to concentrated bands of interference which can be noticed when tuning the bands or a short wave portable RX, I assume this provides the 472KHz dip. It is really bad at 136 KHz see this picture from my gallery of filth. http://i221.photobucket.com/albums/dd243/radiotalk/zjo_grab600.jpg I did try braid breakers on the main offender, mains and antenna feeder, there was no change what so ever. The interference in the SW BC Bands is also imposed on my telephone line and those in the street right up to the nearest BT cabinet. Unfortunately BC stations can still be heard on a SW 'tranny' providing you are not too close to the source TV, within 10ft through a brick wall, so I cant claim BC interference. > > > If you are on good terms with your neighbour it might be worth drawing > their attention to the licence conditions, and suggest they contact > their supplier, as you may have to make a complaint. The supplier > might be more "sensitive" than the neighbour, you may then suggest a > "cure" to try. The RSGB did used to stock these filters which are > normally used for VHF but are very effective for SMPSU radiation. I am on good terms with them, I told them in good humor when they put their house on the market that I would be so pleased to see the back them with their Panasonic, unfortunately the recession meant there were no buyers. Still the new buyers could have 2 or 3 Panasonic's aye. I contacted Panasonic on their behalf, to be fair they offered to investigate, however, I know that the set is no worse than any other example of the same model. In that case any call out would be chargeable and futile, a fact which they agreed. > > It does work and these problems can be cured. Panasonic Plasma problems are know worldwide they are the worst offenders among all the plasma bad technology. The only cure which my neighbor will not accept is a lead box around all 6 sides including the screen. The final 'cure' will be failure in time although prior to that I understand the QRM will get worse as the set ages, thankfully it is old technology and there is very little likelihood of a replacement being Plasma > 73 Eddie