Ramsey Electronics FT146 - Manual (Page 10)

FT146 • 10
❒ 21. Install R15, 10K ohm (brown-black-orange).
❒ 22. Install C33, .001 uf disc capacitor (marked .001, 1 nf or 102).
❒ 23. Install R16, 10K ohm, (brown-black-orange).
Time for a breather and progress check. So far, we've built up the audio section
of our transmitter, from microphone amplifier to low pass filter to buffer stage -
not bad for less than an hour! Give a quick check to see that you've installed all
parts in the correct places and that all joints are soldered nicely with no
splashes or bridges.
❒ 24. Install R24, 2.2K ohm (red-red-red).
❒ 25. Install R23, 10K ohm (brown-black-orange).
❒ 26. Identify Q7, a 2N3906 PNP transistor (marked 221334). Do not
confuse it with the other transistors in your kit. Position Q7's large flat side
as shown in the parts layout diagram. Press the transistor snugly into the
PC board so that only a minimum amount of wire lead is exposed above
the board. In soldering, do not be afraid of using enough heat to make a
good solid connection.
❒ 27. Install R21, 2.2K ohm (red-red-red).
❒ 28. Install C45, .001 uf (marked .001, 1 nf or 102).
❒ 29. Install R25, 470 ohm (yellow-violet-brown).
❒ 30. Install R11, 1K ohm (brown-black-red).
❒ 31. Install R27, 10K ohm (brown-black-orange).
❒ 32. Install R12, 10K ohm (brown-black-orange).
❒ 33. Install D1, BB609 varactor diode (small black body with yellow band).
Varactor diodes act as voltage variable capacitors. In his case, D1's
capacitance is varied by the amplified voltage from your microphone,
causing the crystal oscillator's frequency to change - in exact step with your
voice. Voila, FM or Frequency Modulation!
❒ 34. Install C35, .01 uf (marked .01 or 103 or 10 nf).
❒ 35. Install C32, .001 uf disc capacitor (marked .001, 1 nf or 102).
❒ 36. Install R26, 10K ohm (brown-black-orange).
❒ 37. Install R5, 47K ohm (yellow-violet-orange).
❒ 38. Install C24, 100 pf disc capacitor (marked 100 or 101).
❒ 39. Install C30, 470 pf disc capacitor (marked 470 or 471).
❒ 40. Install R8, 270 ohm (red-violet-brown).