[TenTec] Re: 1 kHz IMD with Preamp ON/OFF

[Sinisa Hristov]

"Marijan Miletic, S56A" wrote:
 
> >Looking at the filter there are only 4 crystals.
 
> Each crystal has series and parallel resonance which makes 8 pole filter!

Well, formally that's correct, but for ages it has been customary
to indicate number of poles according to the equivalent low-pass
filter. For bandpass filters this means 4 crystals = 4 "poles".


> It is difficult to achieve 1 kHz filter shape factor better then 1:3 at 9
> MHz.

Inrad has much better shapes at much lower bandwidths.


73,

Sinisa  YT1NT, VA3TTN