RE: OP1 and CW filter gain difference?

Posted by Don Wilhelm-3 on Apr 08, 2005; 7:48pm
URL: http://elecraft.85.s1.nabble.com/OP1-and-CW-filter-gain-difference-tp376780p376782.html

Marteinn,

The CW filter design point is for a bandwidth of 400 to 600 Hz, and it may
be that what you are seeing is normal - the high ripple with a bandwidth
greater than about 1.2 kHz is quite normal.  Greater attenuation does appear
at narrow bandwidth, but if that area is important to you, you may want to
experiment by changing the turns ratio of T7 a bit to see if it improves.

73,
Don W3FPR

> -----Original Message-----
>
>
> Vic and Stewart, Tanks for answering
>
> well, the ripple on the CW filter at 2kHz BW is abt 8db p-p.
>
> the gain difference when the CW filter is offset to 1.2kHz
> (for digital modes) and its BW is 1kHz is abt -3dB relative to
> the OP1 filter (not bad?).
>
> with the same at 200Hz BW the gain is -10dB relative to the OP1.
>
> Maybe this is normal,
>
> 73 de TF3MA
> --
>

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