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Message-ID: <20070416001449.dgwt70bsck08k40s@webmail.versatel.de>
Date: Mon, 16 Apr 2007 00:14:49 +0200
From: uwe-jannsen@versanet.de
To: rsgb_lf_group@blacksheep.org
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Subject: LF: [500]  Low pass filtering
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Status: O

Hi David,
I built that Chebyshev low pass filter. the attenuation here is 36dB at the
second and 63dB at the third harmonic ? that?s what I expected.
now my class D PA can be switched to the 137kHz LPF  or to that above 
mentioned
LPF.

BTW. The only modification of the class D  G0MRF / G3YXM PA to run it 
at 500kHz
I made: reducing the stability resistors R20 and R21 to 4,8R. With 10R or 6,8R
it doesn?t work because the rectangular drive signs are deformed to somewhat
like spikes. (D4 and D5 are not installed).

thanks Dave

regards
Uwe/dj8wx