SHORTWAVE CONVERTER Parts List C1 Optional capacitor. Try 150pF with 5 Mhz crystal, or 47pF with 8 Mhz If using crystal ò 10 Mhz omit this capacitor. Omit this capacitor if reception is stronger without it. C2 33 pF C3,C5 220 pF C4 .047 æF D1 Zener diode, either 5.1v or 6.2v (2N4691 or equivalent) R1 1Kê, ¬ watt resistor U1 NE602AN Frequency Converter IC T1 10.7 Mhz miniature IF transformer (green plastic screw) XTAL 5 Mhz or 8 Mhz crystal, or other values (see text file XTAL.TXT) One for each band you like to listen to 8-pin DIP socket (for U1) J1,J2 RCA jacks [J2 is optional, see note 3 below] Motorola plug (optional). If installing converter externally, use for connecting cable to car radio's antenna jack). Radio Shack part #274-711 14-pin wire-wrap socket and 14-pin DIP headers for mounting crystals Optional (see file XTAL.TXT) Hookup wire Schematic ========= ÚÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÂÄÄÄÄÂÄÄ/\/\/\Ä +12v ÃÄÄÄĶÄÄÄÄÄ´ ³ ³ R1 ³ C2 ÄÄÁÄÄ ³ ³ ÄÁÄC3 ÚÄÄÄ¿ xtal ³ ³ ÄÂÄ ÀÄÄÄÙ ³ ³ ³ ÄÄÂÄÄ ³ ³ J2 (to car radio antenna jack) ³ ³ ³ ³ ÚÄÄ¿ C5 ÚÄÄÁÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÁ¿ ³ ³ oÄÄÄÄÄÄÄĶÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄ´ 7 6 8³ ³ ÀÄÂÙ ³5 ³ ³ ðgnd ³ U1 ³ ³ ³ ³ ³ J1 (ant.) ÚÄÄÄÄÄÄÄÄÄ¿ ³ NE602 ³ ³ ¿ D1 ÚÄÄ¿ ³ 3ÃÄÄÄÄÄÂÄÄÄÄ´1 ³ ÃÄÄÄÄ´ÄÄÄÄÄÄÄÄ¿ ³ oÄÄÄÄÄÄÄÄ´1 ³ ³ ³ Frequency ³ ³ À ³ ÀÄÂÙ ³ T1 4ÃÄnc ÄÁÄC1*³ Converter ³ ³ ³ ³ ³ ³ ÄÂÄ ³ ³ ³ ³ ÃÄÄÄÄÄÄÄÄ´2 ³ ³ ³ ³ ÄÁÄ ³ ³ ³ 5ÃÄÄÄÄÄÁÄÄÄÄ´2 ³ ÄÂÄ C4 ³ ³ ÀÄÄÄÄÄÄÄÄÄÙ ³ 3 ³ ³ ³ ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÂÄÄÄÄÄÄÄÄÄÄÙ ³ ³ ³ ³ ³ ³ ÀÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÄÅÄÄÄÄÄÄÄÄÄÄÄÄÄÄÁÄÄÄÄÄÄÄÄÄÄÄÄÄÄÙ ðgnd *see text ÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜÜ Notes: 1) Virtually any construction method (point-to-point wiring, wire wrapping, etc.) should work, but a printed circuit board is recommended for both ease and neatness of construction. PC board construction would probably also help minimize undesirable RF interference from strong local broadcast stations. See file READ.ME for source of etched PC board. "Universal" type PC boards, such as the ones available at Radio Shack [part # 276- 170], also work fine. Parts layout is not critical, but keep lead length short. 2) Connect external antenna to J1 (it works with anything over 2', but better results are obtained with longer lengths, especially on the lower short wave frequencies. A 15' "random wire" antenna gives excellent results, as does an old TV "rabbit ear" antenna. 3) J2 connects to car radio's antenna jack. If mounting the converter inside the car radio, omit J2 and run a wire directly from where the center connector of J2 is indicated to the car radio's antenna jack, otherwise use coax cable to connect from J2 to car radio antenna jack (see note 3). 4) It is suggested that you install the converter inside the chassis of the car radio (it simplifies the wiring and reduces noise). If you do not have room to do so, use a metal case for the converter and a short length of shielded coax cable for the connection from the converter to the car radio's antenna jack [if you do not wish to use coax, even hookup wire seems to work o.k., without much noise or interference pick up]. 5) Connect +12 volt power input to car radio's on/off switch. That way you can turn both radio and converter on with that switch. 6) When everything is working, tune in a shortwave station near the middle of the dial and adjust the slug of T1 for the strongest signal. 7) You may use a signal generator or crystal oscillator to calibrate the dial, if desired. 8) If using the radio inside a car, hooked to car's 12-volt circuit, you must use an external antenna going outside the car or you will get no signals. 9) Short wave reception is much better at night on most bands, especially the lower frequency ones. ============================================================================= Erratum: Earlier versions of this file failed to show C2 connected between pins 6 and 7 of the NE602. This is now correctly shown.