From: David Taylor (email@example.com)
In the belief that Toko inductors were not available here, I have been
experimenting with winding high value inductors (100 and 120mH) on toroids
to make the 1kHz lowpass filter for the R2 that was sent to the list by
However, a search of a catalog from a Sydney based mail order Co. called
'Farnell Electronics' revealed that they stock the Toko 10RB series chokes
in values from 33 to 120mH. I could have saved myself a lot of winding!!
I now have the required values and am putting together the filter to test,
and am wondering what the higher Q of my hand wound inductors will do to
filter performance. My coils are typically 10ohm while the commercial ones
are ~70ohm. I can always reduce the effective Q with parallel resistors.
The filter is a 7th order elliptical low pass filter with f.cutoff of 850Hz
and minimum stopband attenuation of 70dB intended for CW reception.
Interested in any comments.....
72 David VK3JKP
RMIT (Bundoora Campus)
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