Return-Path: Received: from post.thorcom.com (post.thorcom.com [195.171.43.25]) by mtain-dl03.r1000.mx.aol.com (Internet Inbound) with ESMTP id D6BD13800009F; Sun, 23 Dec 2012 12:54:47 -0500 (EST) Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1Tmpju-0005K4-4O for rs_out_1@blacksheep.org; Sun, 23 Dec 2012 17:53:30 +0000 Received: from [195.171.43.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1Tmpjt-0005Jv-5Q for rsgb_lf_group@blacksheep.org; Sun, 23 Dec 2012 17:53:29 +0000 Received: from mtaout03-winn.ispmail.ntl.com ([81.103.221.49]) by relay1.thorcom.net with esmtp (Exim 4.77) (envelope-from ) id 1Tmpjq-0005Vm-5q for rsgb_lf_group@blacksheep.org; Sun, 23 Dec 2012 17:53:28 +0000 Received: from know-smtpout-1.server.virginmedia.net ([62.254.123.3]) by mtaout03-winn.ispmail.ntl.com (InterMail vM.7.08.04.00 201-2186-134-20080326) with ESMTP id <20121223175305.CKKZ1579.mtaout03-winn.ispmail.ntl.com@know-smtpout-1.server.virginmedia.net> for ; Sun, 23 Dec 2012 17:53:05 +0000 Received: from [92.235.222.208] (helo=MPC) by know-smtpout-1.server.virginmedia.net with smtp (Exim 4.63) (envelope-from ) id 1Tmpj2-00057B-5L for rsgb_lf_group@blacksheep.org; Sun, 23 Dec 2012 17:52:36 +0000 Message-ID: <248E35A16F4D4A91851CDC0AE9DDAEC4@MPC> From: "Mark" To: References: <3B3F364C54F24112B0098F814D576658@MPC> In-Reply-To: Date: Sun, 23 Dec 2012 17:51:48 -0000 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-Cloudmark-Analysis: v=1.1 cv=AUhbpHVS+xhHrj9wLCYAQoYnFLYUZdbP8UM0GmH2jwk= c=1 sm=0 a=pnycYrcEI5sA:10 a=3NElcqgl2aoA:10 a=a5Gf7U6LAAAA:8 a=F3M5lZpKAAAA:8 a=q7NKKO8oAAAA:8 a=oCcaPWc0AAAA:8 a=alCSdqtGpVzPb0GCd-YA:9 a=wPNLvfGTeEIA:10 a=NKqc0qoa-VgA:10 a=PXleNfF2eV8A:10 a=yHIqe9kG5mgA:10 a=wk6s2zzMB60A:10 a=fPn4HB79UYkHzJhw:21 a=6bLkeGMjOfO_YbpR:21 a=pGLkceISAAAA:8 a=pSDxxfrZAAAA:8 a=E93lBu2AAAAA:8 a=Kfh8keCelzEVopAoZzEA:9 a=_W_S_7VecoQA:10 a=tXsnliwV7b4A:10 a=MSl-tDqOz04A:10 a=uAS8W6cBDDQA:10 a=8y3r-Fxw0wcA:10 a=ZUHL7eEe4EUA:10 a=8lfLvbM9VgMA:10 a=NWVoK91CQyQA:10 a=vcySb2sHtm2Q5tlU:21 a=HpAAvcLHHh0Zw7uRqdWCyQ==:117 X-Spam-Score: 0.3 (/) 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: Warren and all For a single service 1/4 wave system that may be true, my point is that there is a VERY REAL RISK of injury from these systems especially in the UK Many of the MF broadcast systems here have multi-coupled transmitters, and the mast is not a 1/4 wave at all these frequencies. The medium wave band spans about an octave. On smaller systems the antenna is electrically quite short compared to 1/4 wave. The DPI is frequency dependant but can be quite high (at least in the reactive part) leading to very high voltages at the base.. Multiplied by 4 or more transmitters each running 50 to 200kW of AM Mast base insulators that i am familiar with are typically rated at 120kV and there are some systems where the peak voltage here is the limiting factor for the numbers of services we can actually run into the antenna at once. I have seen small mammals and birds bridge the spark gaps.. there is not much left after. if an arc is generated, it ionises the air along the path, and this forms quite a good conductor to the nearest earth. If the nearest earth is you... Arcs are also capable of being sustained for quite a while.. they do not necessarily cause the transmitters to trip. [...] Content analysis details: (0.3 points, 5.0 required) pts rule name description ---- ---------------------- -------------------------------------------------- -0.0 RCVD_IN_DNSWL_NONE RBL: Sender listed at http://www.dnswl.org/, no trust [81.103.221.49 listed in list.dnswl.org] 0.3 URIBL_RHS_DOB Contains an URI of a new domain (Day Old Bread) [URIs: blacksheep.org] -0.0 SPF_PASS SPF: sender matches SPF record 0.0 HTML_MESSAGE BODY: HTML included in message X-Scan-Signature: 9c6f861813be21b949fefb381c49ca48 Subject: Re: LF: Unusual radio mast video Ukraine ?? Content-Type: multipart/alternative; boundary="----=_NextPart_000_001B_01CDE136.2E82CCA0" 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-sid: 3039ac1d4ad150d745670152 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_001B_01CDE136.2E82CCA0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable Warren and all For a single service 1/4 wave system that may be true, my point is that = there is a VERY REAL RISK of injury from these systems especially in = the UK Many of the MF broadcast systems here have multi-coupled transmitters, = and the mast is not a 1/4 wave at all these frequencies. The medium wave = band spans about an octave. On smaller systems the antenna is = electrically quite short compared to 1/4 wave. The DPI is frequency dependant but can be quite high (at least in the = reactive part) leading to very high voltages at the base.. Multiplied by = 4 or more transmitters each running 50 to 200kW of AM Mast base insulators that i am familiar with are typically rated at = 120kV and there are some systems where the peak voltage here is the = limiting factor for the numbers of services we can actually run into the = antenna at once. I have seen small mammals and birds bridge the spark gaps.. there is = not much left after. if an arc is generated, it ionises the air along the path, and this = forms quite a good conductor to the nearest earth. If the nearest = earth is you...=20 Arcs are also capable of being sustained for quite a while.. they do = not necessarily cause the transmitters to trip. A brief note about the effects of MF RF currents The current will actually flow mostly over / through the upper layers of = your skin, you will not be electrocuted. That would be a kindness You will however be subjected to extreme temperatures associated with = the plasma of the arc. These will be worst at entry and exit points for = the RF current flow. The guy holding the plants in the video almost certainly had small burns = under his gloves, as an arc would form there too. That's why he was = felt pain without there being any obvious cause (from the video) The effect would be like touching an arc welder.. there is probably not = enough voltage to do any harm, but would you put you finger where the = arc was struck? RF burns wont necessarily kill you but lying helpless and undiscovered = because you have severe burns etc. and can't walk, could. I am merely pointing out that what the guys in the Ukraine did was = incredibly foolish, but they got lucky. If someone were to try the same trick on the wrong site they may not be = able to post their exploits on Youtube From: Warren Ziegler=20 Sent: Sunday, December 23, 2012 4:58 PM To: rsgb_lf_group=20 Subject: Re: LF: Unusual radio mast video Ukraine ?? Mark,=20 I don't know what the power of the system is but I suspect that = since at the base of 1/4 wave antenna the voltage is lowest this might = be running substantial power. Also note that they are drawing arcs with = grass, not metal or a graphite pencil. Very likely that they would have = been killed if they had used a metal spike to draw the arc or if they = had been standing on damp ground etc. 73 Warren K2ORS On Sun, Dec 23, 2012 at 8:10 AM, Mark = wrote: All The antenna in the Ukrainian video looks to be quite a low power = system. If you try that on a high power system you would suffer serious = injury or even death. The arcs drawn in the video were a few mm long. I have seen arcs from = high power systems over 6" long and some considerably longer. Once an = arc starts it can self sustain, even bypassing the path that started = it.. if you became part of the path to earth things would vaporise = quickly, including parts of you. These systems are very dangerous. Don't try this at home (or on a = local radio transmitter site) You have been warned. Mark GM4ISM Broadcast engineer... From: Graham=20 Sent: Sunday, December 23, 2012 12:28 PM To: rsgb_lf_group@blacksheep.org=20 Subject: LF: Unusual radio mast video Ukraine ?? What are they saying ? other than ' oh golly gosh , that a = bit warm' =20 G.. = http://www.southgatearc.org/news/december2012/unusual_radio_mast_video.ht= m?utm_source=3Dfeedburner&utm_medium=3Demail&utm_campaign=3DFeed%3A+Amate= urRadioNews+%28Southgate+Amateur+Radio+News%29#.UNb27Kya98E No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.2805 / Virus Database: 2637/5978 - Release Date: = 12/22/12 --=20 73 Warren K2ORS WD2XGJ=20 WD2XSH/23 WE2XEB/2 WE2XGR/1 =20 No virus found in this message. Checked by AVG - www.avg.com Version: 2013.0.2805 / Virus Database: 2637/5978 - Release Date: = 12/22/12 ------=_NextPart_000_001B_01CDE136.2E82CCA0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
Warren and all
For a single service 1/4 wave system that may = be true,=20 my point is that there is a VERY REAL RISK of injury  from these = systems=20 especially in the UK
Many of the MF broadcast = systems here have=20 multi-coupled transmitters, and the mast is not a 1/4 wave at all = these=20 frequencies. The medium wave band spans about an octave. On smaller = systems the=20 antenna is electrically quite short compared to 1/4 wave.
 The DPI is frequency = dependant but can=20 be quite high (at least in the reactive part) leading to very high = voltages at=20 the base.. Multiplied by 4 or more transmitters each = running 50=20 to 200kW of AM
 Mast base insulators that i am familiar=20 with are typically rated at 120kV and there are some = systems=20 where the peak voltage here is the limiting factor for the numbers of = services=20 we can actually run into the antenna at once.
 I have seen small mammals and birds = bridge the=20 spark gaps..  there is not much left after.
 if an arc is generated, it ionises the = air along=20 the path, and this forms quite a good conductor to the nearest = earth. =20   If the nearest earth is you...
 Arcs are also capable of being sustained = for quite=20 a while.. they do not necessarily cause the transmitters to = trip.
 
 
A brief note about the effects of MF RF=20 currents
The current will actually flow mostly over / = through the=20 upper layers of your skin, you will not be electrocuted. That would be a = kindness
You will however be subjected to extreme = temperatures=20 associated with the plasma of the arc. These will be worst at entry and = exit=20 points for the RF current flow.
The guy holding the plants in the video almost = certainly=20 had small burns under his gloves, as an arc would form there = too. =20 That's why he was felt pain without there being any obvious cause = (from the=20 video)
The effect would be like touching an arc = welder.. there=20 is probably not enough voltage to do any harm, but would you put you = finger=20 where the arc was struck?
RF burns wont necessarily kill you but lying = helpless=20 and undiscovered because you have severe burns etc. and can't walk,=20 could.
 
I am merely pointing out that what the guys in = the=20 Ukraine did was incredibly foolish, but they got lucky.
If someone were to try the same trick on the = wrong site=20 they may not be able to post their exploits on Youtube
 
 

From: Warren Ziegler
Sent: Sunday, December 23, 2012 4:58 PM
To: rsgb_lf_group
Subject: Re: LF: Unusual radio mast video Ukraine=20 ??

Mark,=20
       I don't know what the power of the = system is but=20 I suspect that since at the base of 1/4 wave antenna the voltage is = lowest this=20 might be running substantial power. Also note that they are drawing arcs = with=20 grass, not metal or a graphite pencil. Very likely that they would have = been=20 killed if they had used a metal spike to draw the arc or if they had = been=20 standing on damp ground etc.

73 Warren K2ORS



On Sun, Dec 23, 2012 at 8:10 AM, Mark <markhughes1@blueyonder.co.uk> wrote:
All
The antenna in the  Ukrainian = video looks to=20 be quite a low power system.
If you try that on a high power = system  you=20 would suffer serious injury or even death.
The arcs drawn in the video were a few mm = long. I have=20 seen arcs from high power systems over 6" long  and some=20 considerably longer.  Once an arc starts it can self sustain, = even=20 bypassing the path that started it..
 if you became part of the path to = earth things=20 would vaporise quickly, including parts of you.
 These systems are very = dangerous.  Don't=20 try this at home (or on a local radio transmitter site)
 
You have been warned.
Mark GM4ISM
 Broadcast engineer...
 
 

From: Graham =
Sent: Sunday, December 23, 2012 12:28 PM
To: rsgb_lf_group@blacksheep.org
Subject: LF: Unusual radio mast video Ukraine = ??

What  are  they  saying  ?  other =20 than  ' oh  golly  gosh , that a bit  warm'  =
 
G..
 
 
 
 
http://www.southgatearc.org/news/december2012/unusual_rad= io_mast_video.htm?utm_source=3Dfeedburner&utm_medium=3Demail&utm_= campaign=3DFeed%3A+AmateurRadioNews+%28Southgate+Amateur+Radio+News%29#.U= Nb27Kya98E

No virus found in this = message.
Checked by=20 AVG - www.avg.com
Version:=20 2013.0.2805 / Virus Database: 2637/5978 - Release Date:=20 12/22/12




--
73 Warren K2ORS
        =  =20       WD2XGJ
          =    =20   WD2XSH/23
              =  =20 WE2XEB/2
               =20 WE2XGR/1

 

No virus found in this=20 message.
Checked by AVG - www.avg.com
Version: 2013.0.2805 / = Virus=20 Database: 2637/5978 - Release Date: 12/22/12

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