On Mon, Feb 26, 2024 at 07:43 PM, <natereik@...> wrote:
? ? Am I understanding that you were finding T37-17s to measure 25%+ high when you wound them?? And your further work with T37-10s is validating your measurements?
From Material 17 I used the size 30 (T30-17). Validation by using T37-10 showed two things: 1. My setup brought probably to high values for L. 2. Despite the deviance (see No 1) the AL of the T30-17 (QMX) could be probably a little bit to high but probably not +25% or more.
With 12 turns on a T37-17, I was somewhere around 0.35uH. Taking it all the way down to 8 turns got me 0.22 ?H
These values are not consistent. Reducing from 12 turns to 8 should reduce the inductivity by theory from 0.35 ?H to 0.16 ?H (not the measured 0.22 ?H). Did you use the same allocation of turns across the toroid?
I'm considering building a whole LPF on a breadboard
Please be aware of the different stray capacitance and the capacity of the connected QDX circuits. And use a rf suitable board!!!
My final result of my whole testing was: Following the manual brings good results or at least a good start point to tweak the filters.
