Re: gEDA-user: OFF: OFWK2954 by Siemens

[Wojciech Kazubski <wk0@xxxxx>]

This is multistsndard B/G + D/K filter for TV, it has relatively wide passband (about 6MHz) located between 32 and 38MHz. SAW filters have also significant in-band attenuation, up to 20dB, so more gain is needed before them and this is not good for HF radio. 
Unless you do need wideband ATV, the best solution is 45MHz crystal filter but it is hard to get. 
Also LC filter with high Q inductors should work better than TV filters, if you can tune them properly.

Some info on OFWK2954:
http://radio.elektroda.net/pdf/filtry-saw.pdf - list of TV IF filters, one line on OFWK2954 (in polish)

Also ITME (http://www.itme.edu.pl/PRsurface.htm) makes some equivalents of similar filters (datasheets are in MS Word)

SAW filters are now manufactured by EPCOS http://www.epcs.com

Wojciech Kazubski
> Hi list,
> 
> Could anyone provide me information about the SAW filter produced by Siemens
> named OFWK2954. I can't find any documentation about it. I'm designing a HAM
> radio, and looking for filters.
> 
> Currently I am designing the first, wide band I.F.
> 
> Thanks,
> 
> -- 
> Levente
> http://web.interware.hu/lekovacs
> 
> 
> 
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