Message-ID: <4BEE898A.2000503@iup.uni-heidelberg.de>
Date: Sat, 15 May 2010 13:46:18 +0200
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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To: rsgb_lf_group@blacksheep.org
References: <AANLkTin3w2PmwROGFzODvFcUO5-AL0vUyq8C7INdUYAe@mail.gmail.com>, <28093526.109907.1273582377168.JavaMail.fmail@mwmweb078>, <AANLkTil1Sx9v3lHUNUuJLm6EWcbmy0rsMMPHgyf58I3w@mail.gmail.com> <4BE97E93.12009.23FC007@dave.davesergeant.com> <4BE9ABA8.5000801@iup.uni-heidelberg.de> <001801caf38d$f1f3de70$0401a8c0@xphd97xgq27nyf>
In-Reply-To: <001801caf38d$f1f3de70$0401a8c0@xphd97xgq27nyf>
Subject: Re: LF: Re: TV transformer
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Mal,

It is used in my test antenna, for local tests. I tried to reach my 
grabber out of a distance of 1,1km (home QTH to work QTH). Generally 
this is a method to become on air for a first step but is not suitable 
for DX.

You need some 10kV on your antenna (me too), so there is no alternative 
of winding a big air coil like Markus(DF6NM), Paul(W1VLF), Stefan(DK7FC)...

I estimate you need at least 500mA antenna current to reach >500km but 
within the UK you could start with such a transformer.

I used the transformer just as a normal voltage transformer that was 
connected to a small antenna, 8m long, 3m up. But you could arrange an 
air gap in the ferrite part to adjust the L of the secondary to resonate 
your antenna! So, the PA has not to handle too much reactive power and 
harmonics are better filtered.
Place the transformer not in shack but on the antenna because it is very 
loud ;-)

73 es gl,

Stefan/DK7FC

Am 14.05.2010 19:50, schrieb mal hamilton:
> Stefan
> What is this transformer actually doing ?
> mal/g3kev

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Mal, <br>
<br>
It is used in my test antenna, for local tests. I tried to reach my
grabber out of a distance of 1,1km (home QTH to work QTH). Generally
this is a method to become on air for a first step but is not suitable
for DX. <br>
<br>
You need some 10kV on your antenna (me too), so there is no alternative
of winding a big air coil like Markus(DF6NM), Paul(W1VLF),
Stefan(DK7FC)...<br>
<br>
I estimate you need at least 500mA antenna current to reach &gt;500km
but within the UK you could start with such a transformer.<br>
<br>
I used the transformer just as a normal voltage transformer that was
connected to a small antenna, 8m long, 3m up. But you could arrange an
air gap in the ferrite part to adjust the L of the secondary to
resonate your antenna! So, the PA has not to handle too much reactive
power and harmonics are better filtered.<br>
Place the transformer not in shack but on the antenna because it is
very loud ;-)<br>
<br>
73 es gl,<br>
<br>
Stefan/DK7FC<br>
<br>
Am 14.05.2010 19:50, schrieb mal hamilton:
<blockquote cite="mid:001801caf38d$f1f3de70$0401a8c0@xphd97xgq27nyf"   type="cite">
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  <div><font face="Arial" size="2">Stefan</font></div>
  <div><font face="Arial" size="2">What is this transformer actually
doing ?</font></div>
  <div><font face="Arial" size="2">mal/g3kev</font></div>
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