Message-ID: <4E480E02.9020706@iup.uni-heidelberg.de>
Date: Sun, 14 Aug 2011 20:03:46 +0200
From: =?UTF-8?B?U3RlZmFuIFNjaMOkZmVy?= <Stefan.Schaefer@iup.uni-heidelberg.de>
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References: <68BE37BD69E54DEE89CEBA8E30E9B94E@PcMinto> <4E47FFE9.10100@iup.uni-heidelberg.de> <3ED8E5422F1F45DBB8186E9D9870AD63@PcMinto>
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Subject: Re: LF: Re: 137 grabbers
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Minto, Daniele,

@Daniele: Nice to read you also want to join in on LF! BTW VLF is not=20
forgotten here, i want to come back in September. But want to have the=20
LF system ready for the DX season and wat for lower QRN on the Dreamers=20
Band...
You don't have a licence and cannot TX? Wouldn't it be worth to learn=20
for a licence for that reason? :-)
And have you done further tests on sferics and so on your remote VLF=20
QTH? Any news?
Just got re-fascinated by John/F5VLF about the earth antenna stuff and=20
want to do more experiments on that antenna again but LF improvements=20
are very time consuming! But i have holidays now :-))) I am curious how=20
the earth antenna performs as a RX antenna on 137 kHz (directional=20
pattern and gain and noise). As a TX antenna i will be to lossy i think=20
and its not worth the effort carrying 100s of kg of batteries on the=20
hill for doing some CQ calls that are not answered....

@Minto:
Am 14.08.2011 19:33, schrieb Minto Witteveen:
>
> Above 10 MHz the gain drops off rapidly, it is nearly useless at 14=20
> MHz. a -77 type would be much worse there I think.
>
Sure. I just talked about LF now. I read the -43 type is suitable for=20
40...400 MHz, at least this is said in the catalog...
>
> As for the Q: I did a comparison between an FT50-43 and a 14 mm 4C6=20
> (for my 137 KHz low-pass filter, see my website). The Q of the FT50-43=20
> coil was abt 50, the 4C6 =E2=80=93 with a lower Al - was 140 !!
>
Interesting! 140 at which L? I am searching for ferrite cores to achieve=20
a high Q on LF, in the range of 100...1000uH. Where can i get these=20
cores? At RS? Where do you buy them? They are usually samller, cheaper=20
and easier to handle than pot cores.

BTW what do you think about a ferrite RX antenna for LF? Now i'm opening=20
an older discussion i expect ;-)

73, Stefan/DK7FC



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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
  <meta content=3D"text/html; charset=3DUTF-8" http-equiv=3D"Content-Type=
">
</head>
<body bgcolor=3D"#ffffff" text=3D"#000000">
Minto, Daniele, <br>
<br>
@Daniele: Nice to read you also want to join in on LF! BTW VLF is not
forgotten here, i want to come back in September. But want to have the
LF system ready for the DX season and wat for lower QRN on the Dreamers
Band...<br>
You don't have a licence and cannot TX? Wouldn't it be worth to learn
for a licence for that reason? :-)<br>
And have you done further tests on sferics and so on your remote VLF
QTH? Any news?<br>
Just got re-fascinated by John/F5VLF about the earth antenna stuff and
want to do more experiments on that antenna again but LF improvements
are very time consuming! But i have holidays now :-))) I am curious how
the earth antenna performs as a RX antenna on 137 kHz (directional
pattern and gain and noise). As a TX antenna i will be to lossy i think
and its not worth the effort carrying 100s of kg of batteries on the
hill for doing some CQ calls that are not answered....<br>
<br>
@Minto:<br>
Am 14.08.2011 19:33, schrieb Minto Witteveen:
<blockquote cite=3D"mid:3ED8E5422F1F45DBB8186E9D9870AD63@PcMinto"
 type=3D"cite">
  <div dir=3D"ltr">
  <div
 style=3D"font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 10pt;">
  <div>
  <p style=3D"margin: 0in 0in 10pt;" class=3D"MsoNormal"><font size=3D"3"=
><font
 face=3D"Calibri">Above 10 MHz the gain drops off rapidly, it is nearly
useless at 14 MHz. a -77 type would be much worse there I think.<br>
  </font></font></p>
  </div>
  </div>
  </div>
</blockquote>
Sure. I just talked about LF now. I read the -43 type is suitable for
40...400 MHz, at least this is said in the catalog...<br>
<blockquote cite=3D"mid:3ED8E5422F1F45DBB8186E9D9870AD63@PcMinto"
 type=3D"cite">
  <div dir=3D"ltr">
  <div
 style=3D"font-family: 'Arial'; color: rgb(0, 0, 0); font-size: 10pt;">
  <div>
  <p style=3D"margin: 0in 0in 10pt;" class=3D"MsoNormal"><font size=3D"3"=
><font
 face=3D"Calibri">As for the Q: I did a comparison between an FT50-43 and
a 14 mm 4C6 (for my 137 KHz low-pass filter, see my website). The Q of
the FT50-43 coil was abt 50, the 4C6 =E2=80=93 with a lower Al - was 140 =
!!</font></font></p>
  </div>
  </div>
  </div>
</blockquote>
Interesting! 140 at which L? I am searching for ferrite cores to
achieve a high Q on LF, in the range of 100...1000uH. Where can i get
these cores? At RS? Where do you buy them? They are usually samller,
cheaper and easier to handle than pot cores.<br>
<br>
BTW what do you think about a ferrite RX antenna for LF? Now i'm
opening an older discussion i expect ;-)<br>
<br>
73, Stefan/DK7FC<br>
<font size=3D"3"><font face=3D"Calibri"><br>
</font></font><br>
</body>
</html>

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