Re: Max nr of poles in CW-filter ?

Heikki wrote:
>Having built several ladder filters for SSB (8.. 10 MHz, 4 ..  8 poles)
>with BW abt. 2 kHz (mainly for TX applications) I would like to try a
>narrow filter (BW 500 or even less). One  thing I am worried about is
>the insertion loss. Has anyone any experience regarding the maximum
>number of poles (= crystals) in such narrow filters. I have seen designs
>for SSB with 14 poles but some doubts exist if this would be excessive
>in a CW filter.
>73 de oh2lzi (Heikki)

Heikki - See QST for 8/78, 12/78 and 11/80 for answers.
If I have room, I put a mini trimmer cap in series with each xtal
to tune all the xtals to the exact same frequency. 
This helps the bandwidth and reduces the insertion loss.
73 W7ZFB