DL2MAN wrote: ↑30 Mar 2022, 11:26
Ohwenzelph wrote: ↑30 Mar 2022, 01:56
For the (tr)uSDX with 3 BS170's, On schematic and in Bom C10 is 68 pF and is C11 none, but in the “alternative band setups” it looks to me like they should add up to 128pF.
The Schmematic contains tried, trued and tested values (that I found based on the theoretical values by experimenting, repeating and testing) while the "alternative band setups" are just theoretical values. Whenever in doubt: Schematic contains the working stuff.
Someone still needs to find the "practical" values for the higher Bands. So far noone has made anything out of this it seems and we won´t do it.... So here´s your chance to contribute to (tr)uSDX.
73 Manuel, DL2MAN
I did replace the 30M for 15M on L21 L22 and then shifted to Classic selection
I replace L21 with a T37-6 9T and L22 with T37-6 6T
I took off 1 condenser on C20-C22-C24-C28
Remove C27 and put the one i removed on C20 to replace( i do not have a good inventory yet but it is coming)
Results were fine except for the second harmonic is close to 46MHz try to tweak L22 adding and removing a turn cannot get closer so keep it 6T, i should replace some condenser values but i have to learn the effect of each one. I am only on a learning process with electronic and began with this forum and all the info i got here and on internet.
Here are the result i got first on the board from *Rxxxx*. I replace the T37-43 with some from Digikey (plastic coated) I have better % eff 60% with the ones that came with the kit
On the Lo LPF
12V - W - % - PA Bias max
80M 5.18 46.2 172
60M 2.41 46.5 172
40M 3.0 47.6 172
30M 2.57 43.5 172
20M 3.52 46 172
On the Classic LPF
15M 3.20 46 172
80M 5.1 46 172
My work is more instinctive than technical so any help or reference will be accepted
All i did here i found info on this forum (like how measure LPF with nanovna) i have one
for two week now gift of a friend. Will keep trying to tune it.
Also i do that on my own, the risk is large that i scrapt it but i like trying things, so think
about it before trying that.