Bandpass filter - UK Vintage Radio Repair and Restoration Discussion Forum

Mike Brett · 30th Nov 2009, 3:03 pm

Hello all
I have just built a 80 meter bandpass filter for my Superhet receiver. I used the circuit from Radcom page 20 of the Feburary 2006 issue. I could not get the Toko coils for it so used toroids instead, tuned by variable capacitors of which there are three. Now as this is the first one I have ever built I am at a loss as how to tune it. Do you just twiddle the capacitors for maximum volume or is there a set way to go about it.I have tried it on my main shack radio and it seems to work ok as it lets the 80 meter signals through but blockes out the other bands, I just need to fine tune it somehow.
Mike

30th Nov 2009, 3:03 pm	#1
Mike Brett Retired Dormant Member Join Date: Dec 2005 Location: Wisbech, Cambridgeshire, UK. Posts: 452	Bandpass filter Hello all I have just built a 80 meter bandpass filter for my Superhet receiver. I used the circuit from Radcom page 20 of the Feburary 2006 issue. I could not get the Toko coils for it so used toroids instead, tuned by variable capacitors of which there are three. Now as this is the first one I have ever built I am at a loss as how to tune it. Do you just twiddle the capacitors for maximum volume or is there a set way to go about it.I have tried it on my main shack radio and it seems to work ok as it lets the 80 meter signals through but blockes out the other bands, I just need to fine tune it somehow. Mike