Re: Core for Output Transformer

Kelly Jack

Hi all,

Have been following this thread keenly and modding and checking at stages on the way.

Completed in the following order.

Q90 to 2n2222a sot23.
220pf caps on all 7 driver chain emitter resistors.
MPSH10 in for the next two.

All good up to here. Drive pot at halfway. 14w at 40m, 3w at 10m. Power 13.8v.  Each step showed some improvement in power at 10m (which started at 1w).

Next step - next 4 transistors changed to MPSH10 and things go backwards. Power at 10m down to 1.5W and power on lower bands is less also.

hfe on the MPSH10 ranged from 120 to 135. 2n3904 were much higher.

No other changes made so everything else stock in the transmit chain. Even at full RV1 I cannot achieve power levels I was getting before the last step.

Wasnt expecting this result and wondering if Ive got some dud MPSH10 to replace.


Simon VK3ELH 

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