“READY-DESIGNED” DUAL TUNED BANDPASS FILTERS [50 ohms input/output] A series of Bandpass Filters designed for the input tuning of amateur band receivers by G QRP Club member Stefen Niewiadomski from his book The Filter Handbook. The filters are designed for 50 ohm input/output impedance and may be cascaded for better roll-off outside the passband. The TOKO coils also have a tap on the tuned winding which is useful for matching into input circuit of the order of 1k ohm. The designs use off-the shelf TOKO coils. The designations for the coils are the part number - once available in the UK. The inductors are variable [core tuned] but the mean inductance is given for matching to other inductors. From : The FILTER HANDBOOK Stefen Niewiadomski Heineman Newnes 1989 ISBN 0-434-91378-2
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The named inductors might be a little rare nowadays. If you find a source, please let G4WIF know.
