write all on pcb

Guys could i use , Cu wire copper of 1.5mm , just i want to use if it work at max of 80W , 100W .
Thanks.

Quote from: Radioclick1fm on November 28, 2025, 06:59:03 am

Guys could i use , Cu wire copper of 1.5mm , just i want to use if it work at max of 80W , 100W .
Thanks.

in that case you need inductance  recalculation,   if remeber 98nH in out, midddle 108nH

Thank you rigmo , i will see what i have , when i finish it .It could took some time .

Hi here,

Am a new user.

The disadvantage of a double-side printed circuit under the tracks is that you more insertion losses and what is forget here, is that the total capacity also increases.
Of course you should not mount this PCB flat on the metal but a little bit above it.

I have the best experience with "floating" filters with the coils is separate (with shielding).
If you don't do that, the harmonics will (happily) blow over.

Without special (high price) measuring equipment (Vector Network Analyzer) you actually have no idea what you are doing.

Marcel

Hi,

It's quite difficult to achieve the following with an open construction on the printed circuit board.
I've tried everything but 'floating with shielding between the coils work best.

See attached photos which only consists of 3 coils ans 4 capacitors.

Use ceramic tube capacitors of at least 500V.

I used these up to about 200W without any problems.
These did have slightly higher losses than silver-plated(Semco)capacitors or ATC type 100B.

That's quite similar to the ones we make, but we put screens between the coils.  I compared the filters with and without the screens, and the improvement in the higher harmonic products was significant with the screens in place.

The best filters we use (for higher power gear) use coax lines as resonant stubs, tweaked accurately for the frequency in use.  The higher power gear always uses pairs of output devices, which has the advantage of tending to null even harmonics.  The normally predominant 2f harmonic is several dB lower than the 3f before filtering if the PA is accurately balanced!  This has the advantage of reducing the stringency of the filters needed, especially for the lower harmonic products.

With a conventional filter like the one Zozo shows above, it's crucial to have really low impedance earthing and make sure that the PA is accurately impedance-matched to the filter to minimise losses and to minimise heating problems.  It's interesting to play with the "sense" of the windings - you can get a couple of extra dB of harmonic suppression by winding the first coil clockwise, the next anticlockwise, and so on.  The improvement is marginal but reducing the mutual coupling between coils helps a little.