These are great, Oliver. If it's okay with you, could you send me the hi-rez versions of the graphs? Al and I would like to include them in the book.
BTW, I tweaked the toroids in the LPF board to match their table values. As it turns out, they are very close as is. I fiddled with the turn spacing on a few, but did not have to add or subtract turns for any toroid. I've attached the table. Below is the first band in the table to illustrate what the file contains:
Band Inductor
Type (Core) ????Turns ???? Wire Length
The wire length is taken from the Kits and Parts table () but I changed the wire length to account for the #20 gauge wire that is suggested if you plan to use Bill's 100W PA. (The K&P table is for #26 gauge wire and the 20W PA.) I also added about an inch to each length so you have enough for generous pigtails. Alas, the Crochet Hook Method for winding cores doesn't lend itself to the heavier gauge and small core diameter. Just take your time and you'll be fine.
I will also be posting the table to the SCHR site.
Jack, W8TEE
On Sunday, February 16, 2025 at 02:23:34 PM EST, Oliver KI3P via groups.io <oliver@...> wrote:
?
I wound another V12 bandpass filter board to replace the prototype board in my radio. I'm pretty happy with the performance. Here are some plots showing the measured transmission curves for all the channels.
?
?
?
I measured and tweaked the inductance for every core and ended up with values that often differ from the recommended values. You can find a fill write up with all the details of the core windings and a comparison of each filter to the ELSIE simulation on my blog here:
Jack, W8TEE