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Message-ID: <FDCC39D43D974DED978401025DB874DF@lindavideo>
From: "Ken" <ken.h.wright@btinternet.com>
To: <rsgb_lf_group@blacksheep.org>
Date: Thu, 16 Dec 2010 20:06:18 -0000
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Subject: LF: Sound Card mic Impedance
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Thank you all LFs.
Thank you for all the info that you sent me, it looks they can be anyt=
hing from 4k ohms upwards, this is ok for me, I am doing  a Low Pass=
 Filter to use with Winrad, F1, 20kHz, F2, 30 kHz, 100kHz -80 dB (theo=
retical) with a characteristic impedance of 50 ohms, with this high in=
put impedance I can locate the filter very close to the sound card mic=
 input and terminate the filter output with a 50 ohm resistor. Hopeful=
ly this will eliminate the BC intermod I was experiencing when trying=
 to receive Chris G3XIZ the other day.

73
Ken
M0KHW   I091TV=20

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<DIV><FONT size=3D2 face=3DArial>Thank you all LFs.</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>Thank you for all the info that you=
 sent me, it=20
looks they can be anything from 4k ohms upwards, this is ok for me, I=
 am=20
doing&nbsp; a Low Pass Filter to use with Winrad, F1, 20kHz, F2, 30 kH=
z, 100kHz=20
-80 dB (theoretical)&nbsp;with a characteristic impedance of 50 ohms,=
 with this=20
high input impedance&nbsp;I can&nbsp;locate the filter very close to=
 the sound=20
card mic input and terminate the filter output with a 50 ohm=20
resistor.&nbsp;Hopefully this will eliminate the BC intermod I was exp=
eriencing=20
when trying to receive Chris G3XIZ the other day.</FONT></DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT size=3D2 face=3DArial>73</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>Ken</FONT></DIV>
<DIV><FONT size=3D2 face=3DArial>M0KHW&nbsp;&nbsp;=20
I091TV</FONT>&nbsp;</DIV></BODY></HTML>

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