Tonight I finished working on the 80m filter.
I have detached the second, now unused, case, tidied the filter up and added the screws to secure the sides.
I measured the insertion loss once fully assembled and it is about 1.1 dB across the VK 80m band (3.500 – 3.800 MHz).
The coils I have used for L1, L2 and L4 are 14 turns each on 25 mm diameter formers. L3 is 8.75 turns, also on a 25 mm former.
I have begun working on the 160 m filter and I have prepared the chassis and wound the 3 large inductors. Again I have used different size former as the required 2 inch Schedule 40 PVC is not on hand. Instead I have used 55 mm diameter PVC pipe and I have added an extra turn.
I won’t have time to finish the 160 m filter before the weekend so it will have to wait until the RD contest in August for final testing.