Return-Path: Received: from rly-mh12.mx.aol.com (rly-mh12.mail.aol.com [172.21.166.148]) by air-mh04.mail.aol.com (v123.4) with ESMTP id MAILINMH043-61f49e72aff2ce; Thu, 16 Apr 2009 08:56:58 -0400 Received: from post.thorcom.com (post.thorcom.com [193.82.116.20]) by rly-mh12.mx.aol.com (v123.4) with ESMTP id MAILRELAYINMH122-61f49e72aff2ce; Thu, 16 Apr 2009 08:56:33 -0400 Received: from majordom by post.thorcom.com with local (Exim 4.14) id 1LuR7z-0001oz-8s for rs_out_1@blacksheep.org; Thu, 16 Apr 2009 13:55:39 +0100 Received: from [193.82.116.32] (helo=relay1.thorcom.net) by post.thorcom.com with esmtp (Exim 4.14) id 1LuR7y-0001oq-K6 for rsgb_lf_group@blacksheep.org; Thu, 16 Apr 2009 13:55:38 +0100 Received: from vms173019pub.verizon.net ([206.46.173.19]) by relay1.thorcom.net with esmtp (Exim 4.63) (envelope-from ) id 1LuR7v-0003HM-P7 for rsgb_lf_group@blacksheep.org; Thu, 16 Apr 2009 13:55:38 +0100 Received: from DR2 ([71.184.212.10]) by vms173019.mailsrvcs.net (Sun Java(tm) System Messaging Server 6.3-7.04 (built Sep 26 2008; 32bit)) with ESMTPA id <0KI700MW22K4OICN@vms173019.mailsrvcs.net> for rsgb_lf_group@blacksheep.org; Thu, 16 Apr 2009 07:55:17 -0500 (CDT) Message-id: From: "dave.riley3" To: References: <38F4A9873A5B474DB6FB337B1B69ABA10D7B925641@HERMES8.ds.leeds.ac.uk> <000c01c9be89$9ff54c60$6c01a8c0@DELL4> Date: Thu, 16 Apr 2009 08:55:15 -0400 MIME-version: 1.0 X-Priority: 3 X-MSMail-priority: Normal X-Mailer: Microsoft Outlook Express 6.00.2900.5512 X-MIMEOLE: Produced By Microsoft MimeOLE V6.00.2900.5579 X-Karma: unknown: X-Spam-Score: 3.4 (+++) X-Spam-Report: autolearn=disabled,FORGED_MUA_OUTLOOK=3.36,HTML_MESSAGE=0.001 Subject: LF: Re: Re: Arcs and sparks - user beware too Content-type: multipart/alternative; boundary="----=_NextPart_000_0044_01C9BE71.0F325AF0" X-Spam-Checker-Version: SpamAssassin 2.63 (2004-01-11) on post.thorcom.com X-Spam-Level: *** X-Spam-Status: No, hits=3.1 required=5.0 tests=FORGED_MUA_OUTLOOK,HTML_20_30, HTML_MESSAGE,NO_COST 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-IP: 193.82.116.20 ------=_NextPart_000_0044_01C9BE71.0F325AF0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable In the days of round aircraft engines and wire HF/MF antennas, you could dep= end on a 2-3" arc from either wire against A/C ground while flying through h= eavy weather... Expensive VanDegraf generator... On the flip side, you could light your cig from the antenna terminal of the=20= ART-13 when on a lower frequency... Just hold a pencil lead near RF terminal, key the TX, and VOILA, cigarette l= ighter!!! But that is all gone now... www.radiocom.net/vx6/connie.htm Dave @ /17 qrpp 505.750 CW beacon ----- Original Message -----=20 From: jrusgrove@comcast.net=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, April 16, 2009 7:51 AM Subject: LF: Re: Arcs and sparks - user beware too Electrically charged volcanic ash in a 'cloud' above the antenna? Have obs= erved some pretty impressive flashovers with thunderstorms passing overhead.= =20 Charged ash particles descending on the antenna? Snow, rain and wind stati= c can make a pretty impressive showing...although not like the passing thund= erstorm.=20 Jay ----- Original Message -----=20 From: Laurence BY3A-KL1X China=20 To: rsgb_lf_group@blacksheep.org=20 Sent: Thursday, April 16, 2009 7:19 AM Subject: LF: Arcs and sparks - user beware too Chris - thanks =20 Yes it was very odd and one of those "what?" times in my professional an= d ham career when you really want to check and recheck. =20 The cable was short circuited DC wise at the antennae end via the (worki= ng) Balun at the time it was unscrewed from the coax - I checked this after= wards in case it wasnt. I checked the TX/RX side too - nothing there. =20 So the time the coax had to charge was only the time from disconnection=20= to "touching" which was appx 5 mins. And remember the coax cable was defacto= sitting on the "ground" for 80m. =20 Now - what that charge was is something that Ive been sleeping on. How=20= about a curved ball and seismic activity beneath where I was staying caused=20= by rock movement and the piezo affect caused a field to be generated etc? -=20= ok outlandish, but I was sitting at a base of an active and smouldering volc= ano and daily tremors were felt....Hmm perhaps not so outlandish after all..= .but I did check again and again after the fact and no charge was present ag= ain until we shoved it all back up in the air again a few hours later. =20 However, logically (probably wrongly too given my luck) the amount of "c= " in pfs for 80m of RG213 aint that large and nothing like capable under nor= mal circumstances to give such a wallop. Yes it could charge to many Kv I su= ppose before it reached it breakdown Voltage - and it is a few, but wallop a= nd (White) flash and bang was audible and visible in daylight about 50 metre= s away (!) but what mechanism would cause the inner to get a gradient again=20= the outer,,,,? =20 As I said before, apart for the Whiz Bangs in the deserts of whereever y= ou really wouldnt think a cable could do that - but it did.=20 =20 I learnt a lesson - never, ever presume because a cable is open circuit=20= that its safe - even one that could normally not have a Pd across it, or is=20= sitting on the ground. =20 I seem to remember SIDE - Switch Off, Isolate, Dump and Earth. =20 Chaps - any more suggestions or solutions or was this an enigma? =20 73 Laurence=20 =20 > From: C.Trayner@leeds.ac.uk > To: rsgb_lf_group@blacksheep.org > Date: Thu, 16 Apr 2009 10:07:17 +0100 > Subject: LF: RE: Arcs and sparks - user beware >=20 > Dear Laurence, >=20 > Thanks for your post. > > (Its got a bit of MF in it honest)=20 > Whether it has or not, it could save one of our lives some day! >=20 > A friend who worked for the London Electricity Board years ago told me= a similar story about working on 3-phase underground cables. You disconnect= both ends, then before you touch them you short each phase to earth. Rarely= will you have happened to disconnect at the zero-volts part of the cycle, s= o apparently you get some satisfying bangs. >=20 > But that may not completely explain your recent experience. One would=20= guess that (a) you turned off the Tx before unplugging the aerial and (b) th= e Tx has a DC path across the aerial socket (e.g a transfo secondary). So di= d some other process charge up your cable? >=20 > Your experience might suggest that, for those who fiddle with their ae= rials frequently, it might be worth permanently fitting a resistor (100k, sa= y) across the two halves; or two, one from each pole to earth. >=20 >=20 > 73, > Chris G4OKW >=20 >=20 >=20 ---------------------------------------------------------------------------- Rediscover Hotmail=AE: Get quick friend updates right in your inbox. Che= ck it out.=20 ------=_NextPart_000_0044_01C9BE71.0F325AF0 Content-Type: text/html; charset="iso-8859-1" Content-Transfer-Encoding: quoted-printable
In the days of round aircraft en= gines=20 and wire HF/MF antennas, you could depend on a 2-3" arc from either wire aga= inst=20 A/C ground while flying through heavy weather...
Expensive VanDegraf=20 generator...
 
On the flip side, you could ligh= t your=20 cig from the antenna terminal of the ART-13 when on a lower=20 frequency...
Just hold a pencil lead near RF=20 terminal, key the TX, and VOILA, cigarette lighter!!!
 
But that is all gone=20 now...
 
www.radiocom.net/vx6/connie.htm
 
Dave @ /17   &nbs= p;=20 qrpp 505.750 CW beacon
 
 
 
 
----- Original Message -----
jrusgrove@comcast.net
Sent: Thursday, April 16, 2009 7:51= =20 AM
Subject: LF: Re: Arcs and sparks -=20= user=20 beware too

Electrically charged volcanic ash in a 'cloud' abo= ve the=20 antenna? Have observed some pretty impressive flashovers=20 with thunderstorms passing overhead.
 
Charged ash particles descending on the antenna? S= now,=20 rain and wind static can make a pretty impressive showing...although=20= not=20 like the passing thunderstorm. 
 
Jay
----- Original Message -----
Sent: Thursday, April 16, 2009 7:= 19=20 AM
Subject: LF: Arcs and sparks - us= er=20 beware too

Chris - thanks
 
Yes it was very odd and one o= f=20 those "what?" times in my professional and ham career when you really wa= nt=20 to check and recheck.
 
The cable was short circuited DC= =20 wise at the antennae end via the (working) Balun  at the time it wa= s=20 unscrewed from the coax - I checked this afterwards in case it wasnt. I=20 checked the TX/RX side too - nothing there.
 
So th= e=20 time the coax had to charge was only the time from disconnection to=20 "touching" which was appx 5 mins. And remember the coax cable was defact= o=20 sitting on the "ground" for 80m.
 
Now  - what that char= ge=20 was is something that Ive been sleeping on. How about a curved ball and=20 seismic activity beneath where I was staying caused by rock movement and= the=20 piezo affect caused a field to be generated etc? - ok outlandish, but I=20= was=20 sitting at a base of an active and smouldering volcano and daily tremors= =20 were felt....Hmm perhaps not so outlandish after all...but I did check a= gain=20 and again after the fact and no charge was present again until we shoved= it=20 all back up in the air again a few hours later.
 
However,=20 logically (probably wrongly too given my luck) the amount of "c" in= pfs=20 for 80m of RG213 aint that large and nothing like capable under nor= mal=20 circumstances to give such a wallop. Yes it could charge to many Kv I=20 suppose before it reached it breakdown Voltage - and it is a few,=20 but wallop and (White) flash and bang was audible and visible in=20 daylight about 50 metres away (!) but what mechanism would cause the inn= er=20 to get a gradient again the outer,,,,?
 
As I said befor= e,=20 apart for the Whiz Bangs in the deserts of whereever you reall= y=20 wouldnt think a cable could do that - but it did.
 
I learnt= a=20 lesson - never, ever presume because a cable is open circuit that i= ts=20 safe - even one that could normally not have a Pd across it, or is sitti= ng=20 on the ground.
 
I seem to remember SIDE - Switch Off, Isolat= e,=20 Dump and Earth.
 
Chaps -  any more suggestions or solut= ions=20 or was this an enigma?
 
73 Laurence
 
> From:= =20 C.Trayner@leeds.ac.uk
> To: rsgb_lf_group@blacksheep.org
> D= ate:=20 Thu, 16 Apr 2009 10:07:17 +0100
> Subject: LF: RE: Arcs and sparks= -=20 user beware
>
> Dear Laurence,
>
> Thanks for=20= your=20 post.
> > (Its got a bit of MF in it honest)
> Whether i= t=20 has or not, it could save one of our lives some day!
>
> A=20 friend who worked for the London Electricity Board years ago told me a=20 similar story about working on 3-phase underground cables. You disconnec= t=20 both ends, then before you touch them you short each phase to earth. Rar= ely=20 will you have happened to disconnect at the zero-volts part of the cycle= , so=20 apparently you get some satisfying bangs.
>
> But that may=20= not=20 completely explain your recent experience. One would guess that (a) you=20 turned off the Tx before unplugging the aerial and (b) the Tx has a DC p= ath=20 across the aerial socket (e.g a transfo secondary). So did some other=20 process charge up your cable?
>
> Your experience might sug= gest=20 that, for those who fiddle with their aerials frequently, it might be wo= rth=20 permanently fitting a resistor (100k, say) across the two halves; or two= ,=20 one from each pole to earth.
>
>
> 73,
> Chris= =20 G4OKW
>
>
>

Rediscover Hotmail=AE: Get quick friend updates right in your inbox. Check it out.
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