Another archive find.? Saved as "Improved"
20m BPF..
It looks really good as an Elsie model, but no much with the VNA
The Elsie model parts are 162nH/800pf, 3.9uH-33pF,
162nH/800pF...
First time I've used solenoid-wound coils in a l-o-n-g time.?
Toroids weren't working out; too much change with one turn
difference.
So, I used the Air Cores function in mini-ring-core calculator to what-if
and came up with 11 turns #22 with a 1/8th ID: Right at 162nH.
The trimmer is 5-30 pF across 22pF.? Tuning helped the VNA sweep
data results but not enough.? Adjustment of the two input/output
parallel circuits might be useful for better results.? I think
filters with larger inductance and smaller capacitor values work out
better.
Chuck, W5USJ (ex K2OFN)
ARCI 5422, SKCC 19956
EM22cv, Rains Co., Texas
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Chuck, W5USJ
