Return-Path: Received: (qmail 24112 invoked from network); 31 Jul 1999 01:05:45 +0100 Received: from magnus.plus.net.uk (HELO magnus.force9.net) (195.166.128.27) by guiness.force9.net with SMTP; 31 Jul 1999 01:05:45 +0100 Received: (qmail 22587 invoked from network); 31 Jul 1999 00:08:22 -0000 Received: from unknown (HELO post.thorcom.com) (212.172.148.70) by magnus.plus.net.uk with SMTP; 31 Jul 1999 00:08:22 -0000 Received: from majordom by post.thorcom.com with local (Exim 3.02 #1) id 11AMRw-0001i5-00 for rsgb_lf_group-outgoing@blacksheep.org; Sat, 31 Jul 1999 00:52:28 +0100 Received: from kodos.tinet.ie ([159.134.237.29]) by post.thorcom.com with esmtp (Exim 3.02 #1) id 11AMRu-0001i0-00 for rsgb_lf_group@blacksheep.org; Sat, 31 Jul 1999 00:52:27 +0100 Received: from p142.lifford1.tinet.ie ([159.134.235.142] helo=beachwood.tinet.ie) by kodos.tinet.ie with smtp (Exim 2.05 #23) id 11AMRq-00062e-00 for rsgb_lf_group@blacksheep.org; Sat, 31 Jul 1999 00:52:23 +0100 Message-ID: <008101bedae7$0000b720$81eb869f@beachwood.tinet.ie> From: "Finbar O'Connor" To: rsgb_lf_group@blacksheep.org Subject: LF: re:Puffs of smoke Date: Fri, 30 Jul 1999 23:57:59 +0100 MIME-Version: 1.0 Content-Type: text/html; charset=windows-1252 X-Priority: 3 X-MSMail-Priority: Normal X-Mailer: Microsoft Outlook Express 4.72.3110.5 X-MimeOLE: Produced By Microsoft MimeOLE V6.00.2800.1106 Precedence: bulk Reply-To: rsgb_lf_group@blacksheep.org Sender: Content-transfer-encoding: 8bit

I read with interest the message from Dick/PA0SE, regarding his antenna system and fire.

Earlier this year I had a similar problem, when running at high power. At first I used my

antenna wire with its plastic insulation only. This ran through a hole drilled in the hardwood

window frame. However once I ran the rig up to 5 amps, there was a crisp crackle and the

antenna current dropped down to almost zero. Using my Variac, I gradually ran up the power

again and again, but once I would get to about 2.5 amps the insulation would break down.

The more I tried it , the lower the level became for the flashover to occur.

I then added some plastic over the insulation , but I had an interesting result. Rain water ran

down the antenna wire and between the two insulations, with the result that at 5 amps output

the outlet hole in the hardwood window frame would suddenly start emitting puffs of white

smoke in time with the morse code. I could read the morse by smoke signals ( no blankets

required ). If I kept the key down long enough I could dry out the water.

Eventually I found a ceramic standoff with a hollow centre and drilled out a bigger hole in

the window frame for it. I also now put a drip turn in the antenna wire to prevent rain water

running into the feedthrough. Mind you, I have drilled that hole at an angle. I also stuffed the

ends of the ceramic insulator with 'Blu-Tac'. Stops the wind blowing into the shack in Winter.

As they say "No smoke without Fire"

73's Finbar EI0CF