Re: The new uBITX boards are here

Jerry Gaffke
 

Probably not.
DC current into the gates is zilch, so those resistors have nothing to do with gate quiescent voltage.
R97 and R98 set an upper bound for the AC impedance seen by the gates,
since the 0.1uF caps at CV1 and CV2 look like a short to ground at RF.

Going from 47 ohms to 220 ohms means the gates get driven harder at 3.5mhz,
but would have little effect at 30mhz where capacitive loading predominates.
So makes the power disparity between the two even larger.

Drain-to-gate capacitance gives negative feedback,
so not clear to me that this is a mechanism that would put the FET's in danger.

But I do think it's curious.

The WA2EBY has those resistors at 27 ohms.


On Sun, May 27, 2018 at 03:55 pm, M Garza wrote:
This is probably to save the MOSFETS from over voltage during the bias adjustment.
 
Marco - KG5PRT 
. . .

 

On Sun, May 27, 2018, 5:05 PM Philip <philip.g7jur@...> wrote:
Also R97 and R98 220 ohms.

Philip G7JUR

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