The amp itself (actually the first gain stage) is the limitation.? That was done on purpose to make the amp bullet proof (short or open the output to the antenna and things are just fine).? You CAN drive the final stage harder by increasing the feedback resistors on the OPA device.? I was more interested in longevity.?

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When you sell kits that for amateur builders, the fastest way to lose the builders focus is to design the PA (or any other part of the radio) so that its not robust to inadvertent mis-operating.? The uBITx and the sBITx falls into that category.? The final transistors on those radios pop like popcorn… Farhan when through several cycles of redesign to keep his PA transistors intact when the operator mis-stepped.? A lot of people were mad over that and their radios went up on the shelf after the first or second incident.? I don’t design stuff like that.

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I design stuff so that the poor kid in the Caribbean that can barely afford antenna wire much less parts for his new radio if it blows up… doesn’t experience a failure that puts his radio in the closet.? It’s easy to do… its just that very few people do it because they want every Last watt out.? Truth is, my 20W PA is capable of about 45 watts… and will even operate class A (if you really want a very linear signal from it… just by boosting the bias).? But all of this reduces the safe operating margin.? So I under-rate and under-run the amp and keep everyone happy.

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Dr. William J. Schmidt - K9HZ J62K(J68HZ) 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ VP2EHZ

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Owner - Operator

Big Signal Ranch – K9ZC

Staunton, Illinois

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Owner – Operator

Villa Grand Piton – J68HZ

Soufriere, St. Lucia W.I.

Rent it:

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Moderator: North American QRO Group at Groups.IO.

Moderator: Amateur Radio Builders Group at Groups.IO.

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email:? bill@...

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