A Radio Power Amplifier for Not a Lot
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A Radio Power Amplifier for Not a Lot
When building a radio transmitter, unless it’s a very small one indeed, there’s a need for an amplifier before the antenna. This is usually referred to as the power amplifier, or PA. How big your PA is depends on your idea of power, but at the lower end of the power scale a PA can be quite modest. QRP, as lowe power radio is referred to, has a transmit power in the miliwatts or single figure watts. [Guido] is here with a QRP PA that delivers about a watt from 1 to 30 MHz, is made from readily available parts, and costs very little.
Inspired by a circuit from [Harry Lythall], the prototype is built on a piece of stripboard. It’s getting away with using those cheap transistors without heatsinking because it’s a class C design. In other words, it’s in no way linear; instead it’s efficient, but creates harmonics and can’t be used for all modes of transmission. This PA will need a low-pass filter to avoid spraying the airwaves with spurious emissions, and on the bands it’s designed for, is for CW, or Morse, only.
We like it though, as it’s proof that building radios can still be done without a large bank balance. Meanwhile if the world of QRP interests you, it’s something we have explored in the past.
Gli ultimi otto messaggi ricevuti dalla Federazione
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@tess as long as your posts are tagged with the correct language it's quite easy to translate on mastodon!
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@oblomov
Ma no, io spesso ne vedo molti di più in timeline. A volte più di mille da leggere.
@las_lallero
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@luca bene, buttare cibo è proprio una cosa brutta
marcoboh@devianze.city
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Should I create another account for frenchposting?
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@bean «who did Zeus rape TODAY?»
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@marcoboh torno a quel discorso che avevamo già fatto di quelli che buttano il pane avanzato e poi comprano al supermercato sacchetti di plastica con dentro il pane grattugiato…che dire?
@luca
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“Consegna con VOC”
No, non è un vero nome di corriere, ma una sigla generica.
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sabato ho mangiato penne e maccheroni con la bottarga 😋
