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 available in the UK. These can be ordered direct from the USA - see below. The inductors are variable [core tuned] but the mean inductance is given for matching to other inductors.

The named inductors are available in the UK from MAPLIN [sales@maplin.co.uk]

A suggested US supplier for designated TOKO coils is PENSTOCK [800] 736-7862