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Date: Sun, 29 Dec 2013 19:31:56 +0100
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: MF PA
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Am 29.12.2013 19:24, schrieb Bob Raide:
> Stefan;
> Is this amp shown capable of handling 300 + volts like your 137 amp 
> that I believe is similar in design? Bob
>

Hi Bob,

Yes it is.

73, Stefan

> > Date: Sun, 29 Dec 2013 18:59:40 +0100
> > From: Stefan.Schaefer@iup.uni-heidelberg.de
> > To: rsgb_lf_group@blacksheep.org
> > Subject: LF: MF PA
> >
> > Hi Wolf,
> >
> > What type of FETs are you using? The standard IRFPs? Many of them have
> > internal Z diodes, so no addional RC network or Z idode is needed. The
> > losses are there anyway, of course.
> >
> > In some older projects i also played with that critical working point,
> > i.e. where one FET shuts down and the other opens. I've tried simple RC
> > networks (series R, parallel C) with an 100 Ohm trimmer. That worked
> > reasonably but usually it is not even necessary. My small MF PA is 
> using
> > a simple ICL7667 and 2x IRFZ48N (Reichelt...) without problems.
> > My large PA generates up to 1.2 kW, which is also enough to reach 1 W
> > ERP, https://dl.dropboxusercontent.com/u/19882028/MF/mod%20MF%20PA.jpg.
> > It was designed for field experiments (Field day) where MUCH more
> > inefficient antennas will be tested, e.g. in France, next year, if they
> > have the allocation then...
> >
> > 73, GL, Stefan/DK7FC

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Am 29.12.2013 19:24, schrieb Bob Raide:
<blockquote cite="mid:BLU180-W625A89D9EE396343EEE7A8ACCF0@phx.gbl"
 type="cite">
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  <div dir="ltr">Stefan;<br>
Is this amp shown capable of handling 300 + volts like your 137 amp
that I believe is similar in design? Bob<br>
&nbsp;<br>
  </div>
</blockquote>
<br>
Hi Bob, <br>
<br>
Yes it is. <br>
<br>
73, Stefan<br>
<br>
<blockquote cite="mid:BLU180-W625A89D9EE396343EEE7A8ACCF0@phx.gbl"
 type="cite">
  <div dir="ltr">
  <div>&gt; Date: Sun, 29 Dec 2013 18:59:40 +0100<br>
&gt; From: <a class="moz-txt-link-abbreviated" href="mailto:Stefan.Schaefer@iup.uni-heidelberg.de">Stefan.Schaefer@iup.uni-heidelberg.de</a><br>
&gt; To: <a class="moz-txt-link-abbreviated" href="mailto:rsgb_lf_group@blacksheep.org">rsgb_lf_group@blacksheep.org</a><br>
&gt; Subject: LF: MF PA<br>
&gt; <br>
&gt; Hi Wolf,<br>
&gt; <br>
&gt; What type of FETs are you using? The standard IRFPs? Many of them
have <br>
&gt; internal Z diodes, so no addional RC network or Z idode is needed.
The <br>
&gt; losses are there anyway, of course.<br>
&gt; <br>
&gt; In some older projects i also played with that critical working
point, <br>
&gt; i.e. where one FET shuts down and the other opens. I've tried
simple RC <br>
&gt; networks (series R, parallel C) with an 100 Ohm trimmer. That
worked <br>
&gt; reasonably but usually it is not even necessary. My small MF PA is
using <br>
&gt; a simple ICL7667 and 2x IRFZ48N (Reichelt...) without problems.<br>
&gt; My large PA generates up to 1.2 kW, which is also enough to reach
1 W <br>
&gt; ERP,
<a class="moz-txt-link-freetext" href="https://dl.dropboxusercontent.com/u/19882028/MF/mod%20MF%20PA.jpg">https://dl.dropboxusercontent.com/u/19882028/MF/mod%20MF%20PA.jpg</a>. <br>
&gt; It was designed for field experiments (Field day) where MUCH more <br>
&gt; inefficient antennas will be tested, e.g. in France, next year, if
they <br>
&gt; have the allocation then...<br>
&gt; <br>
&gt; 73, GL, Stefan/DK7FC<br>
  </div>
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