Ramsey Electronics STC1 Manuel d'instructions

FM25B • 1 Ramsey Electronics Model No. FM25B Own and operate your own FM Stereo broadcast station. The FM25B has an exceptional synthesize

FM25B • 10 PARTS SUPPLIED WITH FM25B: Note the extra chip capacitors included. Capacitors  7 .001 µF disc capacitors (marked .001, 102 or 1nF)

FM25B • 11 Inductors  1 Shielded can inductor, 0.18 uH [L1]  2 Pre-wound spring style inductors, 44 nH [L2,4]  2 1 µH axial inductors

FM25B • 12 RAMSEY "LEARN-AS-YOU-BUILD" ASSEMBLY STRATEGY As you can see in examining the circuit board and components, there is a bit more

FM25B • 13 • Nip or "trim" all excess wires extending beyond each solder connection, taking care that wire trimmings do not become lodged i

FM25B • 14 socket check to be sure that none of the pins are bent under or outside of the socket. When you’re sure the pins are where they belong, pr

FM25B • 15  16. Install J4, the other stereo jack. Now we’ll install some electrolytic caps. Electrolytic capacitors have a right and wrong way to

FM25B • 16  36. Install C23, .1 µF disc capacitor (marked .1 or 104 or 100 nF).  37. You’ll notice a silkscreen position for C19. This part is no

FM25B • 17  58. Install C6, .047 uF ceramic capacitor (marked .047 or 473).  59. Install R13, 100k ohms (brown-black-yellow).  60. Install Q3,

FM25B • 18 flat to the board before soldering.  73. Ok, you know the drill by now. Install S1, the last switch. If you have a short memory, read th

FM25B • 19  89. Install VR1, the 78L05 +5 volt regulator. This part looks like a transis-tor and like a transistor, it must be place correctly to w

FM25B • 2 PARTIAL LIST OF AVAILABLE KITS RAMSEY TRANSMITTER KITS • FM25B FM Stereo Transmitter • AM1, AM25 AM Transmitters

FM25B • 20 stations but your neighbors may be receiving them, using a good receiver and outdoor antenna. Interfering with such reception is a direct

FM25B • 21 board. With an operating frequency of 107.9 MHz programmed into the DIP switches, there should be around 9.0 volts (+- 0.2 volts or so) at

FM25B • 22 quite well. An external antenna can be used for a larger coverage area if de-sired. Use the RF adjustment control (R25) to fine tune the R

FM25B • 23 through a few feet of coaxial cable (either RG-58, RG-59 or miniature RG-174, available at Radio Shack and other sources). Correct dipole

FM25B • 24 rior wiring of your home or building. Do not attempt such an installation unless you know exactly what to do and not to do. Also, because

FM25B • 25 APPENDIX A: FCC RULES AND INFORMATION The Rules of the FCC (Federal Communications Commission) and your kit built FM Stereo Transmitter. A

FM25B • 26 if you are in doubt) the rules and do not bother the understaffed and busy FCC employees with questions that are clearly answered in the r

FM25B • 27 • a. The "bandwidth" of your transmission is limited to 200 KHz, centered on the actual operating frequency. Since 200 KHz is e

FM25B • 28 • d. The most specific FCC regulation of 88-108 MHz FM Broadcast band unlicensed operation is that the "field strength" of the

FM25B • 29 to "die out" at a specific distance from your antenna, no matter what kind of transmitter power or extra-gain antenna you are us

FM25B • 3 SYNTHESIZED FM STEREO TRANSMITTER KIT Ramsey Publication No. MFM25B Price $5.00 TABLE OF CONTENTS Introduction ...

FM25B • 30 SUMMARY The present edition of Part 15 of the FCC rules does not provide detailed guidance on ALL aspects of using a low-power transmitte

FM25B • 31 10. Do not assume that the mere fact that you purchased this kit gives you any specific right to use it for any purpose beyond generating

FM25B • 32 of private citizens and school-community groups as never before in radio com-munications history. Learn the rules...observe them...and hav

FM25B • 33

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FM25B • 35 The Ramsey Kit Warranty Please read carefully BEFORE calling or writing in about your kit. Most problems can be solved without contacting

FM25B • 36 Price: $5.00 Ramsey Publication No. MFM25B Assembly and Instruction manual for: RAMSEY MODEL NO. FM25B SYNTHESIZED STEREO TRANSMITTER KIT

FM25B • 4 INTRODUCTION The Ramsey FM25B is a true SYNTHESIZED STEREO FM broadcast transmit-ter, which any person may build and use in accordance with

FM25B • 5 CIRCUIT DESCRIPTION We will begin by talking about the power supply of your new FM25B. While a DC power source is provided with the kit, it

FM25B • 6 Crystal X1 along with C9 and C12 form the timing reference of the transmitter. The signal from the crystal network is divided down and used

FM25B • 7 cuit tells the user when their transmitter has locked on frequency and when an applied audio signal is being transmitted. U1:A takes the PL

FM25B • 8 ence crystal (X1) as we discussed before. All the internal operations of U3 are truly amazing! The reference signal of X1 is divided by 4 a

FM25B • 9 FM25B PARTS LAYOUT DIAGRAM