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Showing posts from February 11, 2012

The BLF177 some better result

Few days later I changed the coils in the lowpass filter.
Almost doubled the inductance from the RFsimm calculated values.
Also thicker wire used 1.2mm .  And the Spraque C's replaced by an Arco 80pF compression type trimmer.
Now the heat developed is much lower and the efficiency increased to about 50%.
Great tool RFsimm99  but still I need to do the old solder work to change real components and test again. 
Now the only wish is  having a bit more gain it needs >10W drive for full output.  I can not let out the 1Ohm parasite stopper at the gate. If so i see  oscillations.
I tried a wire trough 1 ferrite pearl   with 3 ferrite rings no drive power came through!  1 ring i had power but the ring got hot!
Messured 1 wire gives about  70nH (at 500kHz)  Those tiny rings do a lot more then thought!
The BLF177 takes a lot RF gate current at low impedance.

A few days  I let it rest it was useless to continue the trial and error method. I went ice-scathing.
Then I did check the  low-pass filter u…