Message-ID: <775D0BEF3A4B453EA682B574FFDB58E3@lindavideo>
From: "Ken" <ken.h.wright@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
References: <F88E4E7623D944FB9658C8C02D8A1B18@lindavideo> <4D1B7B17.2040007@iup.uni-heidelberg.de>
Date: Mon, 3 Jan 2011 09:07:54 -0000
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Subject: Re: LF: DK7FC's VLF Active Antenna
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Hi Stefan.
I have just completed your VLF Active Antenna except for the 4:1 trans=
former, considering all my previous correspondence regarding sound car=
d microphone input impedances being anywhere between 4k ohms and 10k=
 ohms, are you using this as a step - up or step - down transformer,=
 and which sound card input are you using mic or line input? I will be=
 using Winrad 1.32, and was hoping to complete in order to look for Ch=
ris G3XIZ today as his QTH is 20km from my self.
Wishing you good luck with you sub9kHz work in 2011.

73s.
Ken
M0KHW

----- Original Message -----=20
  From: Stefan Sch=E4fer=20
  To: rsgb_lf_group@blacksheep.org=20
  Sent: Wednesday, December 29, 2010 6:16 PM
  Subject: Re: LF: DK7FC's VLF Active Antenna


  Hi Ken,=20

  I have not tested other JFETs so far. Is it just because of the SMD=
 housing? I don't use a SMD PCB but a "free air" soldering. So if this=
 is the problem, just solder the FETs legs directly on the next part,=
 e.g. solder the drain directly on the 390 Ohm resistor. Attached you=
 find a picture that shows how my current used VLF grabber antenna loo=
ks inside. Don't be shocked ;-)

  If you anyway want an alternative, the J310 or the (2SK170) should=
 be possible. There are some parameters like the noise and the gain an=
d the input capacitance which are affecting the performance but this=
 is all not so critical on VLF.

  73, Stefan/DK7FC



  Am 29.12.2010 17:58, schrieb Ken:=20
    Stefan.
    Could you please recommend an equivalent to to BF862 which is not=
 Surface Mount for use in this circuit.
    73s
    Ken
    M0KHW

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<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.0 Transitional//EN">
<HTML><HEAD><TITLE></TITLE>
<META content=3D"text/html; charset=3DISO-8859-1" http-equiv=3DContent=
-Type>
<META name=3DGENERATOR content=3D"MSHTML 8.00.6001.18999"></HEAD>
<BODY bgColor=3D#ffffff text=3D#000000>
<DIV><FONT size=3D2 face=3DArial>Hi Stefan.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>I have just completed your VLF Active=
 Antenna=20
except for the 4:1 transformer, considering all my previous correspond=
ence=20
regarding sound card microphone input impedances being anywhere betwee=
n 4k ohms=20
and 10k ohms, are you using this as a step -&nbsp;up or step - down tr=
ansformer,=20
and which sound card input are you using mic or line input? I will be=
 using=20
Winrad 1.32, and was hoping to complete in order to look for Chris G3X=
IZ today=20
as his QTH is 20km from my self.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>Wishing you good luck with you sub9kH=
z work in=20
2011.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial></FONT>&nbsp;</DIV>
<DIV><FONT size=3D2 face=3DArial>73s.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>Ken</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>M0KHW</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial></FONT>&nbsp;</DIV>
<DIV>----- Original Message ----- </DIV>
<BLOCKQUOTE   style=3D"BORDER-LEFT: #000000 2px solid; PADDING-LEFT:=
 5px; PADDING-RIGHT: 0px; MARGIN-LEFT: 5px; MARGIN-RIGHT: 0px"   dir=
=3Dltr>
  <DIV     style=3D"FONT: 10pt arial; BACKGROUND: #e4e4e4; font-color:=
 black"><B>From:</B>=20
  <A title=3Dschaefer@iup.uni-heidelberg.de     href=3D"mailto:schaefe=
r@iup.uni-heidelberg.de">Stefan Sch=E4fer</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A title=3Drsgb_lf_group@=
blacksheep.org     href=3D"mailto:rsgb_lf_group@blacksheep.org">rsgb_l=
f_group@blacksheep.org</A>=20
  </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Wednesday, December 29,=
 2010 6:16=20
  PM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: LF: DK7FC's VLF=
 Active=20
  Antenna</DIV>
  <DIV><BR></DIV>Hi Ken, <BR><BR>I have not tested other JFETs so far.=
 Is it=20
  just because of the SMD housing? I don't use a SMD PCB but a "free=
 air"=20
  soldering. So if this is the problem, just solder the FETs legs dire=
ctly on=20
  the next part, e.g. solder the drain directly on the 390 Ohm resisto=
r.=20
  Attached you find a picture that shows how my current used VLF grabb=
er antenna=20
  looks inside. Don't be shocked ;-)<BR><BR>If you anyway want an alte=
rnative,=20
  the <U>J310</U> or the (2SK170) should be possible. There are some=
 parameters=20
  like the noise and the gain and the input capacitance which are affe=
cting the=20
  performance but this is all not so critical on VLF.<BR><BR>73,=20
  Stefan/DK7FC<BR><BR><BR><BR>Am 29.12.2010 17:58, schrieb Ken:=20
  <BLOCKQUOTE cite=3Dmid:F88E4E7623D944FB9658C8C02D8A1B18@lindavideo=
       type=3D"cite"><META name=3DGENERATOR content=3D"MSHTML 8.00.600=
1.18999">
    <STYLE></STYLE>

    <DIV><FONT size=3D2 face=3DArial>Stefan.</FONT></DIV>
    <DIV><FONT size=3D2 face=3DArial>Could you please recommend an equ=
ivalent to to=20
    BF862 which is not Surface Mount for use in this circuit.</FONT></=
DIV>
    <DIV><FONT size=3D2 face=3DArial>73s</FONT></DIV>
    <DIV><FONT size=3D2 face=3DArial>Ken</FONT></DIV>
    <DIV><FONT size=3D2   face=3DArial>M0KHW</FONT></DIV></BLOCKQUOTE>=
</BLOCKQUOTE></BODY></HTML>

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