R: [AMPS] RF Choke Forms
Maurizio Panicara
i4jmy@iol.it
Sat, 15 Jan 2000 17:29:39 +0100
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Teflon is electrically very good and relatively easy to work. Although =
expensive, it's a convenient and professional replacement for ceramic =
and glass in RF applications involving consistent power (much more than =
in amateur applications) and very high frequencies. Teflon losses, even =
when used inside a coil, stay minimal and the material itself withstands =
high temperatures too.
Do not use plastic and symilar materials were the losses increase with =
frequency (i.e. nylon) and be aware of risks when using materials which =
might burn in their composite structure if something arcs, therefore =
losing their original insulating property. (i.e. fiberglass)
73,
Mauri I4JMY
----- Original Message -----=20
From: Arne Gjerning=20
To: Amp Ref=20
Sent: Saturday, January 15, 2000 7:13 AM
Subject: [AMPS] RF Choke Forms
I have been advised NOT to use Teflon, Delryn, and a few other =
insulating materials for an RF choke. Instead only use ceramic. It was =
then stated the "D" factor was the reason.=20
OK, but why as I could not find info on this subject in the ARRL =
Handbook. Any help to point me in the direction of knowledge on this =
subject would be appreciated. May as well learn something while =
building my amp. And I want to do it RIGHT.=20
73 de Arne N7KA =20
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http-equiv=3DContent-Type>
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<DIV><FONT face=3DArial size=3D2>Teflon is electrically very good and =
relatively=20
easy to work. Although expensive, it's a convenient and =
professional=20
replacement for ceramic and glass in RF=20
applications involving consistent power (much more than in =
amateur=20
applications) and very high frequencies. Teflon losses, even when=20
used inside a coil, stay minimal and the material itself =
withstands=20
high temperatures too.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Do not use plastic and symilar =
materials were the=20
losses increase with frequency (i.e. nylon) and be aware of risks =
when=20
using materials which might burn</FONT><FONT face=3DArial size=3D2> in =
their=20
composite structure if something arcs, therefore losing their =
original=20
insulating property. (i.e. fiberglass)</FONT></DIV>
<DIV> </DIV>
<DIV><FONT face=3DArial size=3D2>73,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Mauri I4JMY</FONT></DIV>
<DIV> </DIV>
<BLOCKQUOTE=20
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT: =
0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A href=3D"mailto:gjerning@flash.net" title=3Dgjerning@flash.net>Arne =
Gjerning</A>=20
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
href=3D"mailto:amps@contesting.com"=20
title=3Damps@contesting.com>Amp Ref</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, January 15, =
2000 7:13=20
AM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> [AMPS] RF Choke =
Forms</DIV>
<DIV><BR></DIV><FONT face=3DArial,Helvetica><FONT size=3D-1>I have =
been advised=20
NOT to use Teflon, Delryn, and a few other insulating materials for an =
RF=20
choke. Instead only use ceramic. It was then stated the "D" factor was =
the=20
reason.</FONT></FONT><FONT face=3DArial,Helvetica><FONT =
size=3D-1></FONT></FONT>=20
<P><FONT face=3DArial,Helvetica><FONT size=3D-1>OK, but why as I could =
not find=20
info on this subject in the ARRL Handbook. Any help to point me in the =
direction of knowledge on this subject would be appreciated. May =
as well=20
learn something while building my amp. And I want to do it=20
RIGHT.</FONT></FONT><FONT face=3DArial,Helvetica><FONT =
size=3D-1></FONT></FONT>=20
<P><FONT face=3DArial,Helvetica><FONT size=3D-1>73 de Arne=20
N7KA </FONT></FONT>=20
</P></BLOCKQUOTE></BODY></HTML>
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