开云体育

Hello,

the story:
I made a homemade Ubitx. The reception seemed too weak, I tested the different stages and wondered if the 45 MHZ band filter was well centered and rated a good bandwidth (minimum 15 Khz)
if I test the filter with a generator I have the maximum at 45.007300Mhz
I am at 50% of the incoming signal (-3db) at 45.008600 and 45.006050
which will theoretically make a width of 2550 htz (!) no good(?)
Filter is a motorola 20J26 --> unable to find documentation
here on ebay (Come from US to france)!

As I have a nanovna, I thought I would test it with this tool.
So I did a montage based on the PJ case model. PDF file.
the filter is between 2 toroids, each primary connected to the Nano
i have this curve (see file)
more surprising when looking this video from 2mn30 #554 NANOVNA Measuring Various Bandpass Filters - YouTube

And some French ham radio, tell me that a good band filter must have at minimun two band filter like this (see file)

here the story on Ubitx forum
/g/BITX20/topic/calibration_filters/89337641?p=Created%2C%2C%2C20%2C1%2C40%2C0%3A%3Arecentpostdate%2Fsticky%2C%2C%2C20%2C2%2C0%2C89337641%2Cprevid%25253D1649866481766021915%2Cnextid%25253D1649175119081743046&jump=1

So I am lost!
My questions: Does anyone have a way to find the doc of this motorola filter?
How well to test it on a Nano?
The curve does not appear to reflect reality (????)

thank you for your answers and hope you were clear

cdt