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AM25
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41. Install C32, 22 pf disc capacitor [marked 22].
42. Install C31, the other 22 pf disc capacitor.
43. Install C24, .01 µF disc capacitor [marked .01 or 103 or 10nF].
44. Install X1, the 10.24 MHz quartz crystal. Inside this metal can is a
piece of synthetic quartz that has been precision ground to vibrate
precisely at 10.24 million times per second, very similar to a mechanical
tuning fork!
45. Install C25, .01 µF disc capacitor [marked .01 or 103 or 10nF].
46. Install S1, the 8 position DIP switch, it is not important that you orient it
in any direction, just be sure all pins fit fully through the PC board and are
securely soldered. You will select your radio channel frequency by setting
the little switch levers on the switch package.
47. Install C33, .01 µF disc capacitor [marked .01 or 103 or 10nF].
48. Install R2, 4.7K ohm [yellow-violet-red].
That completes most of the PLL control circuitry of your transmitter. Now is a
good time to check your work for any unsoldered connections or other
mishaps. Later stages of the transmitter require extra care, so better to catch
errors now rather than later.
49. Install C19, .001 µF disc capacitor [marked .001 or 102].
50. Install R20, 1 K ohm [brown-black-red].
51. Install C16, 65 pF trimmer capacitor. Don’t use too much heat as you
can melt the plastic parts of the capacitor.
52. Install R9, 10K ohm [brown-black-orange].
53. Install Q5, another 2N3904 transistor.
54. Install C20, .01 µF disc capacitor [marked .01 or 103 or 10nF].
55. Install R15, 51 ohm [green-brown-black].
56. Install R16, 2.2K ohm [red-red-red].
57. Install R3, 270 ohm [red-violet-brown].
58. Install C12, .01 µF disc capacitor [marked .01 or 103 or 10nF].
59. Install D1, 1N4148 style glass bead diode; be sure to correctly orient
the banded end of the diode as shown on the PC board.
60. Install C1, a .1 µF disc capacitor [marked .1 or 104]. Watch so you
don’t confuse this capacitor with one of the more common .01 µF types!
61. Install C2, 2200 pF disc capacitor [marked .0022 or 222 or 2200K].
62. Install C6, another 2200 pF disc capacitor.
This completes all of the transmitter RF portion except for the low-pass filter
section and the ‘binocular’ shaped inductors L4 and L6. Let’s get busy winding
these inductors.
Содержание AM25
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