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Am primit pe mail, pare interesant:


The FDIM2019 2N2222 POWER
> We QRP enthusiasts have developed a
> great reputation for doing more
> with less.  Whether that is trying to
> break a record for mile per watt
> in a QSO, or designing a transceiver
> with fewest components, the
> design skills of our colleagues is
> undisputable.  QRPARCI is
> presenting our community with the an
> opportunity to show off these QRP
> design skills with the
> FDIM2019 2N2222 POWER CHALLENGE!  The challenge
> is simple:  Design and demonstrate a
> crystal-controlled 40M PA to make
> the highest sustained power for a
> period of one minute using only two
> 2N2222 transistors.  This event will
> take place at 8:00 PM Friday, May 17
> during FDIM, and the winner recognized
> at the QRPARCI Banquet on
> Saturday, May 18.
> The rules for the competition are
> simple, but we have to list every
> nit-picky detail to test your endurance
> anyway:
> The design is to utilize
> two, 2N2222 or 2N2222A transistors as the
> only active circuit elements.  There
> are no limits on the number of
> diodes, inductors, resistors,
> capacitors, or transformers, but no
> other transistors, tubes, or ICs may be
> used.
> The PA must be crystal controlled
> within the 40M amateur band.
> Builders are encouraged to use their
> own crystals, though there will
> be 7030 kHz HC-49 crystals available at
> the competition.  No external
> frequency source may be used.
> The circuit must fit inside a 12” x
> 12” x 12” volume.  During the
> power test, the judges will cover the
> circuit with a blast shield to
> protect judges and contestants from
> flying bits!
> All circuit components are to be
> visible for inspection.
> A schematic of the circuit is to be
> provided with each entry
> The options for PA cooling are fairly
> open, but there are restrictions
> for safety’s sake:  No cooling media
> may be used that are flammable or
> could emit harmful vapors when
> heated.  The entire cooling systemmust be
> contained  within the 12”x12”x12” volume.
> There is no requirement for harmonic
> purity of the output signal, but
> consider that these designs might be
> published in QQ, so don't get
> stupid.  A 40M harmonic filter will be
> included as part of the test
> equipment to prevent harmonic current
> from affecting power
> measurement.
> A zero-to-24v variable power supply,
> dummy load and power meter will
> be supplied by the judges.
> The competition will have two rounds of
> trials to demonstrate power
> output of each circuit, with the best
> performance of each circuit
> being its final score.
> During each test, the builder will
> connect his circuit, set the power
> supply voltage and then announce to the
> judges when to begin
> measurement.  During a period of one
> minute in which the builder may
> not touch the circuit or power supply,
> the lowest measured power
> during the test will be the score for
> that trial.  Failure
> of the circuit in that one minute test
> period results in a score of
> ZERO for that round!  The winner is
> the circuit generating the highest power score during
> either of his two rounds.
> If the circuit fails during the first
> test period, the builder will
> have five minutes in which to repair it
> before the second round
> trials.  A solder station, simple hand
> tools and a supply of 2N2222As
> will be available.
> If your entry sets off the smoke
> detector in the Holiday Inn, you will
> be disqualified and may be subjected to
> rude laughter and finger
> pointing during the rest of FDIM!
> The winner of the FDIM2019 2N2222A
> POWER CHALLENGE! will be recognized
> at the QRPARCI Banquet Saturday May 18,
> 2018, and famed 2N2222 traveling trophy awarded!
> Questions regarding the POWER CHALLENGE
> may be addressed to David
> Cripe NM0S, [email protected] 
> Good luck and good building!

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12 hours ago, Ion_Bumbu said:

Cu 2 tranzistoare de 600mA/buc la 24Vdc...1W 

Domn` profesor, ma uimiti din nou!

E telegrafie, nimeni nu`si bate capul cu armonici si de mult s`au inventat clasele de functionare F.

Matale cat crezi ca s-ar obtine in RF cu doua tranzistoare asemanatoare cu BC107 ? Eu am sugerat varianta de oscilator in contratimp, asta era esential. Schema n-ar fi o problema. Insa trebuie rezolvata si receptia, cu cele doua tranzistoare in contratimp. Ar merge ceva cu reactie pozitiva. Am inteles eu gresit, nu trebuie si receptor ?

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2 hours ago, VAX said:

Matale cat crezi ca s-ar obtine in RF cu doua tranzistoare asemanatoare cu BC107 ?

Domnule profesor universitar, si vaca si calul au 4 picioare deci sint asemanatoare, la fel si acele 2 tipuri de tranzistori.

Aveti 2N2222 aici sa va edificati:


La o privire superficiala cu 1W putere disipata o pereche ar debita relativ lejer 4W, proiect conventional in clasa C profund, in clasa E...mai mult

Asta ca etaj final clasa C, ca autooscilator pilotat pe Q problema ar fi nivelul pe Q.

Asta asa la prima vedere, dela un umil absolvent de Politehnica...

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Din cate stiu eu, 2N2222 si 2N2219 este acelasi tranzistor la nivel de chip, difera capsula (TO18 vs. TO39).

Si intradevar, in clasa C push-pull si racit bine, poate mai mult decat 1W.

Insa aici este vorba de un concurs al vreunui club destinat sa faca valuri si sa excite "just for fun", eventual rezultand si material pentru publicat... s-a practicat asa ceva si la case mai mari (QST).

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