Envelope-to: dave@picks.force9.co.uk
Delivery-date: Fri, 03 Feb 2006 01:54:19 +0000
From: Warren K2ORS/WD2XGJ <k2ors@comcast.net>
To: rsgb_lf_group@blacksheep.org
Date: Fri, 03 Feb 2006 01:53:40 +0000
Message-Id: <020320060153.24772.43E2B7A400019564000060C422007358340B97010D0A020E06979D0E03@comcast.net>
Subject: Re: LF: Re: Keeping the smoke in
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Hi Laurence,

    I've thought about leaving the box open but I couldn't do that if there was precipitation of any kind. Also might be hazardous to the neighbor's kids - I haven't seen anyone get near it but it's a big chance to take.


--
73 Warren K2ORS/WD2XGJ
FN42hi
http://www.w4dex.com/wd2xgj.htm

 -------------- Original message ----------------------
From: "Laurence KL1X" <hellozerohellozero@hotmail.com>
> No cooling fan Warren just open "ish"  air circulation  without it  things 
> got a little warm especially at 100F ambient in the summer....I love Okie...
> 
> 
> >From: k2ors@comcast.net (Warren K2ORS/WD2XGJ)
> >Reply-To: rsgb_lf_group@blacksheep.org
> >To: rsgb_lf_group@blacksheep.org
> >Subject: Re: LF: Re: Keeping the smoke in
> >Date: Thu, 02 Feb 2006 23:10:18 +0000
> >
> >Hi Mike,
> >
> >    I don't think that the cores were damaged from the last incident. I was 
> >able to run the 250 watt transmitter through it with no problem and no 
> >measureable reflected power. I understand that Laurence also used 3 stacked 
> >FT-290-77s but actively cooled it. A cooling fan is not easy to do in my 
> >case since the tuner is in a weathertight box.
> >
> >--
> >73 Warren K2ORS/WD2XGJ
> >FN42hi
> >http://www.w4dex.com/wd2xgj.htm
> >
> >  -------------- Original message ----------------------
> >From: "MIKE REID" <we0h1@msn.com>
> > > What cores did Laurence use and what wire size & type? Sorry to hear she 
> >failed
> > > again. Maybe the cores got damaged the other day with no external 
> >indications
> > > like cracking or? I don't recall you having trouble with the transformer 
> >when it
> > > was dry and Teflon is way better than cotton so that leads me to think 
> >the cores
> > > were no good after the first heat cycle/failure.
> > >
> > > Mike
> > > WE0H
> > >
> > >   ----- Original Message -----
> > >   From: Warren K2ORS/WD2XGJ
> > >   To: rsgb lf reflector<mailto:rsgb_lf_group@blacksheep.org>
> > >   Cc: LWCA LF Reflector<mailto:lowfer@lwca.org>
> > >   Sent: Thursday, February 02, 2006 4:41 PM
> > >   Subject: LF: Keeping the smoke in
> > >
> > >
> > >   Hello the list,
> > >
> > >         I've heard that the secret to keeping things going in 
> >electronics is to
> > > make sure you don't let the smoke out (that's what makes it all work
> > > apparently).
> > >
> > >        I have again failed to do so. After rewinding my toroidal loop
> > > transformer in the ATU, I had a core overheating problem. The core is 3 
> >stacked
> > > FT-290-77 ferrites.
> > >   After setting the Decca up on QRSS for an hour or so I noticed a 
> >problem with
> > > the rf output current, it was pulsing up and down as if the Decca guard 
> >circuit
> > > was cutting in to protect the PA. So I through the breaker and went out 
> >and
> > > opened the tuner box. Smoke poured out. Bad news. I checked the 
> >temperatures
> > > with a non-contact infra-red thermometer and the toroid core was 343 
> >Farenheit.
> > > The Curie temperature for type 77 ferrite is 200 C (which is 392 
> >Farenheit).
> > > Not sure yet if the core is permanently damaged, I'm still waiting for 
> >it to
> > > cool down.
> > >
> > >        All credit to Laurence who managed to get a loop to work at this 
> >power
> > > level! And especially with the currents he dealt with in the parallel 
> >wire loop
> > > configuration.
> > >
> > >       I guess I need a bigger core than the 3 stacked FT-290-77s any 
> >suggestions
> > > out there?
> > >
> > >   --
> > >   73 Warren K2ORS/WD2XGJ
> > >   FN42hi
> > >   http://www.w4dex.com/wd2xgj.htm<http://www.w4dex.com/wd2xgj.htm>
> > >
> > >
> >
> >
> >
> 
> 
> 
> >From: "MIKE REID" <we0h1@msn.com>
> >To: <rsgb_lf_group@blacksheep.org>
> >Subject: LF: Re: Keeping the smoke in
> >Date: Thu, 2 Feb 2006 22:50:50 +0000
> ><< Multipart4 >>
> 
> 
>