Message-ID: <4ED0E2FF.7080305@iup.uni-heidelberg.de>
Date: Sat, 26 Nov 2011 14:00:47 +0100
From: =?ISO-8859-1?Q?Stefan_Sch=E4fer?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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Subject: Re: LF: 136
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Mal,

I had to change the matching design since i use the new coil, due to its 
very high Q (and so small BW). Now i'm using a ferrite xfmr to transform 
50 Ohm down. The cold end of the coil is in series to the xfmr, i.e. i 
put the RF litz wire 9x through the ferrite xfmr, then through a current 
xmfr (to measure the antenna current) and then directly to the earth system.
Yes, my PA is designed to run at 50 Ohm as well.
The link coulping was quite efficient and provided a galvanic decoupling 
between the different earths. Since it was a resonated primary coil it 
also provided some filtering. Now since i use the xfmr i have to add 
further LCs in the shack. Anyway no problem, some T200-2 are ordered...
My feed cable is RG214, about 8m long...

  73, Stefan

Am 26.11.2011 11:30, schrieb mal hamilton:
> Stefan
> With your new glass coil former how do you match your PA to this coil. 
> Is your PA designed for 50 ohms and coupled to the coil via 50 ohm 
> coax and link coupled via a few turns at the cold end of coil.
> I use a 0.5 mH coil at the bottom of my inv L system to resonate the 
> antenna. The cold end of coil goes to Earth and I TAP up from the 
> Earth end with the centre of my coax to get a match. ! : 1 SWR.  My 
> PA is designed for 50 ohms and I use 50 ohm coax from the shack to the 
> antenna coil about 50 metres away.
> I was wondering if the link coupling is efficient and matches well.
> Your signal is fb at present on 136.172 every day
> de mal/g3kev

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Mal,<br>
<br>
I had to change the matching design since i use the new coil, due to
its very high Q (and so small BW). Now i'm using a ferrite xfmr to
transform 50 Ohm down. The cold end of the coil is in series to the
xfmr, i.e. i put the RF litz wire 9x through the ferrite xfmr, then
through a current xmfr (to measure the antenna current) and then
directly to the earth system.<br>
Yes, my PA is designed to run at 50 Ohm as well.<br>
The link coulping was quite efficient and provided a galvanic
decoupling between the different earths. Since it was a resonated
primary coil it also provided some filtering. Now since i use the xfmr
i have to add further LCs in the shack. Anyway no problem, some T200-2
are ordered...<br>
My feed cable is RG214, about 8m long...<br>
<br>
&nbsp;73, Stefan<br>
<br>
Am 26.11.2011 11:30, schrieb mal hamilton:
<blockquote cite="mid:003601ccac26$6b509680$0401a8c0@xphd97xgq27nyf"
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  <div><font face="Arial">Stefan</font></div>
  <div><font face="Arial">With your new glass coil former how do you
match your PA to this coil. Is your PA designed for 50 ohms and coupled
to the coil via 50 ohm coax and link coupled via a few turns at the
cold end of coil.</font></div>
  <div><font face="Arial">I use a 0.5 mH coil at the bottom of my inv L
system to resonate the antenna. The cold end of coil goes to Earth and
I TAP up from the Earth end with the centre of my coax to get a match.
! : 1 SWR. &nbsp;My PA&nbsp;is designed&nbsp;for 50 ohms and I use&nbsp;50 ohm coax from
the shack to the antenna coil about 50 metres away.</font></div>
  <div><font face="Arial">I was wondering if the link coupling is
efficient and matches well.</font></div>
  <div><font face="Arial">Your signal is fb at present on 136.172 every
day</font></div>
  <div><font face="Arial">de mal/g3kev</font></div>
  <div>&nbsp;</div>
</blockquote>
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