Re: QSX 10W HF Linear PA kit

Timothy Fidler
 

am not sure which three transistor W7ZOI amp you are referring to,  but suggest you look at 

https://qrphb.wordpress.com/2015/02/24/funster-40m-transmitter-from-2014/

which uses a Hayward hyb Cascode amp and subs amplifier to drive a PA - all the early bits are class A.  Enhancements include using two J310 Fets in parallel (Q90 should be a current hog compared to a J310 JFET,  and changing out the final transistor. All done without  magic MMIC .  250 mW Linear should  be possible  ie about 3dB greater than as found.
That 250 mW will give you 8 W out from 3.5 to 30 Mhz if  used with  topology in  Kee's   (Talen) 16 W linear amp.

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