Making a band pass filter, or I hate toroids

I have made some progress on the NE602 direct conversion receiver. I have layed up most the components onto a copper clad board and I now need to add the band pass filter and the front end interface to connect up to an antenna.

I hit a similar problem with the Pixie2 I made previously. I don't have access to any of the named toroids that you find in the HAM radio journals and books. You know, names like T37-6. So I'm doing the numbers to try to lash up a air-space coil instead.

I'm reproducing the 30m QRSS Receiver as built by Hans Summers, G0UPL. Its a hardware defined radio that outouts audio to a peecee to decode.

I have a handful of plastic coil formers that appear to be 1/4" x 1". They have a fiber board on the bottom with five terminals to connect you inductor elements to and your pcb.

So using the calculator at kitsandparts I worked out that following table;

Turns	Inductance
2	0.01uF
5	0.07uF
35	3.67uF

So I've spent half the day crunching the numbers to work out how to get an air-spaced to get the numbers to match the above... The numbers just don't work =/ I'm sure I'll find something and maybe I'll just have to put a bunch of cash aside and make an order to the US.

72,

Kim VK5FNET

new 10m dipole

Replaced the dipole this morning. Cut to length some pvc coated speaker cable that had once been an end fed long wire. Its light and grey so not so easy to see as the red 30amp power cable I was using before. Also ran coax straight up to the center of the dipole and will run a similar arangement to the QRSS Rx of Hans Summers, G0UPL. Now onto modifying the receiver =).

72's

Kim - VK5FNET