Message-ID: <BLU153-W56683361D1B1904848DCBCF7A0@phx.gbl>
From: Laurence KL1 X <hellozerohellozero@hotmail.com>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
Date: Mon, 22 Oct 2012 15:09:26 -0800
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Subject: LF: Heating up Brass question
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With my tuning unit for my 137 kHz LF amplifier the Ceramic feedthru fasten=
ers are Brass 1/4 inch diemater - and are getting a little warm. Brass does=
nt have the best low resistance compared with Copper etc. With the Tx runni=
ng last night full throttle (or close to it) the total loop current was app=
roaching 65A causing the Bolt(s) to get quite warm. The feedthrus are seen =
in the photo going thru the Rubbermaid at the back -  http://kl7uk.com/loop=
1500.jpg   (this is the original tuner - some of the components have change=
d for XPQ) There is probably around 2Kv or more inplaces in the tuner and I=
m seriously considering running the antennae cable straight thru the tub wa=
ll using apporopiate weather proof grommets and using the plastic rubbermai=
d together with the wire insulation into the tuning components as the dilec=
tric -  Im concerned about any heating up of components - but at this kind =
of current its more like designing a car alternator or battery system :-) A=
ny one any pointers or suggestions - Im trying to eliminate any nut bolt co=
nnection as Ohms arent wanted.... Laurence KL 1 X 		 	   		  =

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<BR>With my tuning unit for my 137&nbsp=3BkHz&nbsp=3BLF amplifier the Ceram=
ic feedthru fasteners are Brass 1/4 inch diemater&nbsp=3B- and are getting =
a little warm. Brass doesnt have the best low resistance compared with Copp=
er etc.<BR>&nbsp=3B<BR>With the Tx running last night full throttle (or clo=
se to it) the total loop current was approaching 65A causing the Bolt(s) to=
 get quite warm.<BR>&nbsp=3B<BR>The feedthrus are seen in the photo going t=
hru the Rubbermaid at the back -&nbsp=3B <a href=3D"http://kl7uk.com/loop15=
00.jpg">http://kl7uk.com/loop1500.jpg</a>&nbsp=3B&nbsp=3B (this is the orig=
inal tuner - some of the components have changed for XPQ)<BR>&nbsp=3B<BR>Th=
ere is probably around 2Kv or more inplaces in the tuner and Im seriously c=
onsidering running the antennae cable straight thru the tub wall using appo=
ropiate weather proof grommets and using the plastic rubbermaid together wi=
th the wire insulation into the tuning components as the dilectric&nbsp=3B-=
&nbsp=3B Im concerned about any heating up of components - but at this kind=
 of current its more like designing a car alternator or battery system :-)<=
BR>&nbsp=3B<BR>Any one any pointers or suggestions - Im trying to eliminate=
 any nut bolt connection as Ohms arent wanted....<BR>&nbsp=3B<BR>Laurence K=
L 1 X<BR> 		 	   		  </div></body>
</html>=

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