Please post a linearity plot when you complete it. ?
Dr.?William J. Schmidt - K9HZ J68HZ 8P6HK ZF2HZ PJ4/K9HZ VP5/K9HZ PJ2/K9HZ
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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: www.VillaGrandPiton.com
email:??bill@...
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On Sep 18, 2024, at 2:27?PM, AndyH <awhecker@...> wrote:
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I've decided not to use the K9HZ amp due to its size, and to stick with the QRP-Labs 10 W board with it's much smaller heatsink requirement.? I'm looking for a fairly flat 10 W output from 80 to 10 that will easily fit into the existing uBITX case.
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I think I'll use two stages of slightly modified W8DIZ 2N5109/2SC5551A amps to replace the Q90 and Q911/912 stages.? The attached LTspice model is my current best guess.? The total gain is about 34 dB, with an output of about 1.6-1.65 V peak, slightly above the 1.58 V peak for a 14 dBm input to the QRP-Labs amp.? There appeared to be some gain interactions when adding the second stage - it took a couple of rounds of tweaking to get the gain back in line.? The R14/15/16 pad might need to move up from 3 dB to 4.? We'll see how well hardware mimics spice.
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73, Andy
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K9HZ