Dev,
I remember BEL used to sell the 9mhz filter as Ham filter, I had gone to the crystals division in connection with my old mqth work, had paid 1250 Indian Rupees for the filter along with the the 2 sideband crystals in the year 1992.
After receiving the same from them, I had checked the response in analyzer and I was disappointed with the performance of the filter due to high passband ripple and unsymmetry in the response. It was then I realized that none of the homebrew rigs using the BEL filter ever sounded good.
Instead of chasing this wild goose, you would be better off downloading the spec of the kenwood YK88S filter which is available on the internet and pass it to the chap to retain everything except the center frequency which is 8.830 mhz in that filter.
I wonder why in these modern times anyone has to go behind a lattice filter, especially when one can build a very fine set of ladder filters.
My unsolicited advice is to build a ladder filter in the region of 30 to 38 mhz with a bandwidth of 3 to 5khz and follow it with a Tayloe mod/demod, you could have a nice and simple high performance design. In this case, the tayloe mixer needs to be clocked at 4 X IF. Hence if we make the IF 30Mhz, we can take a readily available 60 Mhz oscillator module, feed it to a push-push doubler using a diode pair and drive the tayloe demod which can be fed to a 4 section polyphase network which would give you the audio from the I/Q stream coming from the tayloe mixer. I have come across a good deal of QEX articles and other projects on the internet that use this concept very effectively.
cheers
de
vu2ttp
--- In HamBrewers@yahoogroups.com, Dev Ramaprabhu <vu2dev@...> wrote:
>
> Dear All,
>
> Season's greetings!
>
> Our morning QTH supplier has promised to help us( Hams+ Homebrewers) in getting/developing 9MHz XTAL filter.
>
> So request the Specification sheet as given out by Ms.BEL or anyone else for that matter.
>
> Thansk and 73s
>
> dev
>
> http://hamrmipl.blogspot.com/
>
>
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