ICE Band Pass Filter Reference

Several reference files found here

Model 419 & Model 419B

Jan 24, 2020

Hi Scott,

I think this is what you need. The spreadsheet has a few part numbers listed for the low bands section. Most of these MICA caps are made by Cornell Dubilier, and are available at mouser.com or Digikey.com. The file ICE 419A.pdf has hand written info at the top. The ten meter section, for example, shows 2 – 540, meaning you need 540 of each side of the relay. Using two of the 270pf to make 540pf splits the current in two, but then requires FOUR 270 pf for that section. Same with the fifteen meter section, you need four 330pf, two per side. Be sure to get caps rated for 1KV or higher. Be careful not to overheat board or connection points on the relay. Some models also have one last series cap near one of the SO-239’s. If yours has one(may or may not), make sure it is good and close to listed tolerance.

I tuned mine by getting the cap values as close as possible, then putting a 50 ohm dummy load on the antenna side and my AA-54 on the radio side, then spread or compress the inductor coils to get lowest loss. Hemostats are great for this. Did this per each band. You should be able to get very close, with a little patience. They can shift a little when you put the cover back on, because of strap capacitance, so check one last time once it is completely re-assembled.

Hope this helps.

MK, K5ER