Re: RD16HHF1 in the uBITX #ubitx

K9HZ <bill@...>
 

Well if you look closely there is some reactance at high frequency in the gate circuit to compensate for high capacitance loading at higher frequency.  Thats a real tight rope to walk though because making that broad-banded is a real trick. 


Dr. William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ

 

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Big Signal Ranch – K9ZC

Staunton, Illinois

 

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Villa Grand Piton - J68HZ

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On Feb 15, 2018, at 2:02 PM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:

The WA2EBY amp has also been simulated, including notes on what those inductor values are:
    https://groups.io/g/BITX20/message/41269

Somehow WA2EBY managed to get good performance without any switching or tuning when changing bands.

Jerry

On Thu, Feb 15, 2018 at 11:47 am, Henning Weddig wrote:

Gordeon, please have a lok on the "famous" WA2EBY amp. He is using inductors in series with teh gate-bias resistors. My explanation is that this inductor of unknown value together with the gate-souce capacitance of the IRF 510 forms a parallel resonator, i.e. cancelling out the high gate capacitance. This may be the reason why he gets a flat(er) frequency response as shown in part 2 of his paper.   

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