LTW455IT Ceramic Bandpass Filter

I was digging about in my pile of crap the other day and came across these IF filters i bought from MiniKits. 455khz IF with 2k -6db bandwidth. So seeing I have not been well for the last couple of weeks, I decided to knock up a schematic using these parts and a bunch of other bits i have sitting here, with the idea of eventually building it.

The audio stages are what I will use in the CW Superhet project, so it was not a total waste of time, same with the RF preamp. Anyway here is the schematic, its unbuilt and untested, so it might be a big pile of crap. You be the judge.


CW RX Update: Band Pass Filter

So i rewound the inductors, after lots of stuffing about I got them ball park.


Ran the filter up in the bode analyzer and well the filter part looks close enough, but it still needs more inductance, maybe another 2 turns per toriod to get the center frequency up to where I want it. Now, that second hump in the plot at 21mhz, I got no idea why that is there, when you look at the next plot where i inject 20mhz into the filter and look at the output on the scope, you will see it does not exist in reality, but shows in the bode analyzer.

Filter output at design frequency.

Frequency output where that hump is on the bode plot. Its obviously an aberration in the analyzer and for now I am not sure why its there.