Indeed measuring is knowing if the final result is in line with the
original expectations.
As mentioned before, it can be easily done with the sound card. At that
time, I asked for feedback (screenshots of the same method) of measured
filters to see if my 4,9 MHz filter is about in line with the 10 MHz
version. If some members do this measurement it is possible to compare
results and find out if it is really a 'lottery'. As I understand, most
builders have their filter dimensioned in accordance with the original
schematic and they all seems to work fine?
OK builders, please download the few kb program, connect your BITX to
the sound card, measure the shape of the filter and post the screendump!
Thanks in advance,
Chris.
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Without measuring to get
good filter is more lottery than predictable result. Only in
situation that somebody can use the same type of crystals producer
and batch results might be comparable.
