woensdag 28 september 2011

Спутник передатчик in SPRAT

It's great to see the Sputnik clone of Michael AA1TJ, on page 30, in the new SPRAT, that arrived today.
Last month I received the Russian tubes 1Ж24Б and 1П24Б to build the transmitter for the Sputnik QSO party, via Peter DL3PB.
Because I don't have any experience with transmitters with tubes, I first studied the proto type transmitter of Michael AA1TJ. Further I studied the excellent info on the page of Peter DL3JIN .
The last questions that I had, after reading those pages, were answered by
Cees PA0CKV and Peter PA0PJE, when I attended the anual meting of the Benelux QRP Club (BQC) in Apeldoorn .
A week ago I started to build the transmitter for the Sputnik QSO Party.
I progress slowly, because I am tired quickly. I also have to build a power supply. I still hope to be ready at the 4th of Oktober for the Sputnik QSO Party.

5 opmerkingen:

  1. Bert,

    Rustig aan met de hoge spanningen. Je hebt nog een week, naast je werk.

    73, Tjeerd

  2. Thanks for the update, Bert!

    I finished my 3-transistor 15m receiver yesterday. Today I'll build the R/T and keying circuit.

    I look forward to working you, Bert. Good luck, OM!

    Beep, beep,
    Mike, AA1TJ

  3. Hallo Tjeerd, Ik de het nog even rustig aan. Ik ben nog niet helemaal de oude. 73, Bert

  4. Hello Michael, All parts of the transmitter are connected. Now I must make a power suply for 70V and 1.2V before I can test.
    How do make the T/R switch?
    Hope to be ready for tuesday. 73, Bert

  5. Hi Bert,

    I used a couple of transistors to switch the anode and screen voltage but a small relay would also do the trick. My circuit also switches on the oscillator supply continuously, for as long as I transmit (in order to reduce keying chirp). But if you are in a pinch for time just key the oscillator along with the PA.

    Please remember that you can use a string of eight 9v transistor radio batteries in series for your high-voltage supply. Since the PA only draws ~14mA on key-down, the batteries should easily last for the entire event. Also, if you use batteries it's simple to tap the series string at six batteries in order to drive your oscillator with ~54Vdc.

    Good luck, Bert. I'll be listening for you, OM!

    Mike, AA1TJ