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Message-ID: <AEFAF8DAD98D4571B7D80E689302E30E@IBM7FFA209F07C>
From: "Chris" <c.ashby435@btinternet.com>
To: "RSGB LF Group" <rsgb_lf_group@blacksheep.org>
Date: Sun, 18 Oct 2009 14:13:31 +0100
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Subject: LF: AF Amps at 136
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Hi All,
Just started constructing TX for 136kHz, noticed Maplin do a Velleman=
 audio PA kit that is rated at 200W (100W RMS into 4R). OK there's no=
 mains transformer or heat sink, but reckon it's good value at =A314.9=
9. Point is the specs also say the minus 3db frequency response is 3Hz=
 / 200kHz.
The RSGB books 'LF Today' refer to using audio amps as PAs at 136 with=
 'a few modifications'. Does anybody know where these modifications ar=
e documented? I guess there's nothing major, reduce a few cap values?=
 Remove Zobel Network etc.?? If anyone has experience with this approa=
ch I would appreciate some hints. Thanks.
Chris, G4AYT, Whitstable.

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<DIV><FONT size=3D2 face=3DArial>Hi All,</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>Just started constructing TX for 136k=
Hz, noticed=20
Maplin do a Velleman audio PA kit that is rated at 200W (100W RMS into=
 4R). OK=20
there's no mains transformer or heat sink, but reckon it's good value=
 at =A314.99.=20
Point is the specs also say the minus 3db&nbsp;frequency response is=
 3Hz&nbsp;/=20
200kHz.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>The RSGB books 'LF Today' refer to us=
ing audio amps=20
as PAs at 136 with 'a few modifications'. Does anybody know where thes=
e=20
modifications are documented? I guess there's nothing major, reduce a=
 few cap=20
values? Remove Zobel Network etc.?? If anyone has experience with this=
 approach=20
I would appreciate some hints. Thanks.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>Chris, G4AYT,=20
Whitstable.</FONT></DIV></BODY></HTML>

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