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Date: Thu, 28 Jun 2012 15:14:33 +0100 (BST)
From: Daniele Tincani <danieletincani@yahoo.com>
To: "rsgb_lf_group@blacksheep.org" <rsgb_lf_group@blacksheep.org>
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Subject: LF: Coupling a LF resonant ferrite rx antenna
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Hello LF,=0A=0A=0Ait seems I managed to build a pretty good ferrite coil (a=
bot 80 turns of Litz wire over a bundle of=A0seven 20cmx1cm rods). Nulling =
and peaking seem acceptable for my purposes. With current var cap, tuning r=
ange is about 160-650 kHz and could=A0easily be moved to lower frequencies =
by adding a parallel fixed capacitor. Until now I have only made some quick=
 tests by inductively coupling the coil with the internal ferrite of a port=
able radio. I would like now to make the antenna suitable also for direct c=
onnection with a 50 ohm input. What do you suggest: to add for example a tr=
ansformer or a buffer amplifier (or both :-))? If a transformer is recommen=
ded, is it advisable to use the main coil as the primary winding?=0A=0A73=
=0ADaniele IZ5WWB
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<html><body><div style=3D"color:#000; background-color:#fff; font-family:Co=
urier New, courier, monaco, monospace, sans-serif;font-size:10pt"><div>Hell=
o LF,</div><div style=3D"font-family: Courier New, courier, monaco, monospa=
ce, sans-serif; font-size: 10pt;"><div style=3D"font-family: times new roma=
n, new york, times, serif; font-size: 12pt;"><div id=3D"yiv1207345417"><div=
><div style=3D"color: rgb(0, 0, 0); font-family: Courier New, courier, mona=
co, monospace, sans-serif; font-size: 10pt; background-color: rgb(255, 255,=
 255);"><div>&nbsp;</div><div>it seems I managed to build a pretty good fer=
rite coil (abot 80 turns of Litz wire over a bundle of&nbsp;seven 20cmx1cm =
rods). Nulling and peaking seem acceptable for my purposes. With current va=
r cap, tuning range is about 160-650 kHz and could&nbsp;easily be moved to =
lower frequencies by adding a parallel fixed capacitor. Until now I have on=
ly made some quick tests by inductively coupling the coil with the internal
 ferrite of a portable radio. I would like now to mak<var id=3D"yiv12073454=
17yui-ie-cursor"></var>e the antenna suitable also for direct connection wi=
th a 50 ohm input. What do you suggest: to add for example a transformer or=
 a buffer amplifier (or both :-))? If a transformer is recommended, is it a=
dvisable to use the main coil as the primary=0A winding?</div><div>&nbsp;</=
div><div>73</div><div>Daniele IZ5WWB</div><div>&nbsp;</div></div></div></di=
v></div> </div>  </div></body></html>
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