Wiring the audio input circuits

We encourage you to peek at the schematic diagram and learn the functions of the following parts. However, the sequence of installation is in the order of convenience and speed. If you wish, insert the parts groupings as one operation, then solder and nip all connections.

ˆ8. Install R1, one of the small yellow trimmer potentiometers marked "102". Don't confuse it with R7 which is marked "104".

ˆ9. Install R4, the other yellow trimmer marked "102". These two trimmers will allow you to adjust the input level.

ˆ10. Install C1, .0047 µF (marked .0047 or 472). If you are building your kit for use in North America or Japan, resistors in steps 11 and 12 are installed as printed. For use in Europe, Russia and some other countries, use 10K ohm resistors in steps 11 and 12. These resistors set the pre-emphasis characteristics for the FM10A. Pre-emphasis is a technique used in FM transmitters to increase the high frequency signal to noise ratio. If you desire a "brighter" sound you may use the 10K ohm resistors rather than the 15K ohm parts.

ˆ11. Install R3, 15K [brown-green-orange].

ˆ12. Install R6, 15K [brown-green-orange].

ˆ13. Install C4, .0047 µF (marked .0047 or 472).

Electrolytic capacitors have a right and wrong way to be installed. Usually, capacitors have a black strip which indicates their ( - ), negative lead and the PC board or Parts Layout Diagram will show the ( + ), positive side of the capacitor's installation hole. Be sure to place the ( + ) capacitor lead into the PC board ( + ) hole and the ( - ) lead into the ( - ) hole. Observe correct polarity when installing the following three electrolytic capacitors:

ˆ14. Install C2, 4.7 or 10 µF. Don’t forget... the proper orientation is noted on the PC board or Parts Layout Diagram.

ˆ15. Install C5, 4.7 or 10 µF. Observe correct polarity.

ˆ16. Install C3, 4.7 or 10 µF. Remember correct polarity.

Diodes also have a right and wrong way to be installed. The cathode (banded) ends face toward the outside of the PC board, away from the IC circuitry. Observe correct polarity when installing the following three diodes.

Page 9 Page 11
Page 10
Image 10
Ramsey Electronics FM10A manual Wiring the audio input circuits
Page 9 Page 11

FM10A specifications

The Ramsey Electronics FM10A is a compact and efficient FM transmitter tailored for hobbyists, educators, and anyone with a passion for creating their own radio broadcast. This device stands out in the world of electronics due to its user-friendly design and array of features that make it an ideal starting point for both beginners and experienced users.

One of the main characteristics of the FM10A is its simplicity in setup and operation. Users can quickly assemble the kit without the need for advanced soldering skills, making it accessible to a broader audience. The transmitter operates in the FM band, allowing for high-quality broadcasts with minimal distortion. Its frequency stability is maintained through a PLL (Phase-Locked Loop) technology, ensuring that the transmitted frequency remains consistent throughout its operation.

The FM10A features adjustable transmission power, allowing users to customize their broadcast range. With a maximum range of approximately one mile under optimal conditions, this device is versatile enough for personal use, small events, or classroom demonstrations. Additionally, the transmitter is equipped with an audio input for connecting various media sources such as smartphones, computers, or other audio devices. This flexibility makes it suitable for a range of applications, from playing music to broadcasting educational content.

Another notable feature is its compact design, which makes the FM10A easy to transport and set up in different locations. The device is powered by a standard 12V supply, which is widely available, making it convenient for users at home or on the go. The lightweight nature of the unit further enhances its portability, enabling users to take their radio broadcasts anywhere.

The FM10A also includes an LED power indicator and a built-in antenna for straightforward operation. Users can enhance their transmitting range by adding an external antenna, providing further customization based on specific needs. The kit comes with comprehensive instructions to guide even those new to radio transmission through each step of assembly and operation.

In addition to its engaging technical features, the FM10A serves as an educational tool. Users can learn about radio frequency technology, electromagnetic theories, and audio broadcasting principles, making it an excellent addition to any STEM program. Overall, the Ramsey Electronics FM10A is a stand-out choice for anyone looking to delve into the world of FM transmission with a robust, user-friendly device that doesn't compromise on quality and functionality.
Top Page Image Contents