❒41. Install R7, 470 ohm (yellow-violet-brown).

❒42. Identify Q1, a 2N3904 NPN transistor (marked 2N3904). Install Q1, observing correct placement of the flat side.

❒43. Install Q2, another 2N3904 NPN transistor (marked 2N3904).Observe correct placement of the flat side.

❒44. Install C27, 15 pf disc capacitor (marked 15 or 15K).

❒45. Install trimmer capacitor, C43 (black body with orange top). This trimmer is used for setting the FT146 exactly on frequency.

❒46. Install Y1, crystal. This is the "heart" of the FM transmitter, producing the initial signal which is multiplied and amplified up to the final transmitted signal. Notice that there are two holes "kitty-corner" around Y1. These holes are used to supply power to the optional crystal oven; they are not used in the standard FT146 kit.

❒47. Install D3, zener diode (gray body with black band). A zener diode functions as a voltage regulator since it has the property of holding the voltage across it constant. In this case we wish to hold the voltage to the crystal oscillator steady to keep us on frequency, even with a poorly regulated disc capacitor power supply.

❒48. Install R28, 100 ohm (brown-black-brown).

❒49. Install R1, 1K ohm (brown-black-red).

❒50. Install JMP3, another wire jumper.

❒51. Install C3, .01 uf (marked .01 or 103 or 10 nf).

❒52. Install C9, .1 uf disc capacitor (marked .1 or 104).

❒53. Install C23, .001 uf disc capacitor (marked .001, 1 nf or 102).

❒54. Install C44, .001 uf disc capacitor (marked .001, 1 nf or 102).

❒55. Install C8, .001 uf disc capacitor (marked .001, 1 nf or 102).

❒56. Install C5, .01 uf disc capacitor (marked .01 or 10 nf or 103).

This completes assembly of the crystal oscillator section of our FM transmitter. If so inclined, we could connect up some power and actually "fire-up" the PC board so far. We'd only be producing a signal at 1/9 of the carrier frequency though, since we've yet to build the multiplier stages.

❒57. Install R3, 47K ohm (yellow-violet-orange).

❒58. Install Q3, 2SC2498 or 2SC2570A NPN VHF transistor (marked C2498 or 2570A). Position the flat side as shown on the parts layout.

❒59. Install C28, 39 pf disc capacitor (marked 39 or 39K).

FT146 • 11

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Ramsey Electronics FT146 manual
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FT146 specifications

The Ramsey Electronics FT146 is a versatile and compact FM transmitter that stands out for its user-friendly operation and impressive performance in both amateur and professional audio applications. Designed for hobbyists, educators, and small businesses alike, the FT146 offers a reliable solution for broadcasting audio signals over a short to moderate range.

One of the main features of the FT146 is its simple plug-and-play setup, which allows users to get started quickly without needing extensive technical knowledge. The device operates with a frequency range of 88.1 to 107.9 MHz, covering the entire FM broadcast band. This flexibility enables users to choose the best frequency for minimal interference in their transmission area. Additionally, with an adjustable output power of up to 2 watts, the FT146 can effectively cover distances ranging from a few hundred feet to several miles, making it ideal for a variety of broadcasting scenarios.

The FT146 utilizes advanced modulation technology to ensure high-quality audio transmission. It supports monophonic audio, which is perfect for clear voice and music transmission. The integrated audio limiter prevents distortion, ensuring that the sound quality remains consistent, even at higher volumes or varying audio signals.

Another notable characteristic of the FT146 is its robust construction. Housed in a durable metal enclosure, the transmitter is built to withstand everyday use. The compact design allows for easy portability, making it suitable for field applications, on-location broadcasting, or as a permanent installation in a small venue.

In terms of connectivity, the FT146 features multiple audio input options, including a 3.5mm jack and RCA inputs. This versatility allows users to connect various audio sources, such as MP3 players, computers, or professional-grade audio equipment.

Furthermore, the FT146 also includes an LED power indicator and a built-in antenna output for enhanced transmission efficiency. Users can either connect an external antenna for increased range or utilize the included telescopic antenna for convenience.

Overall, the Ramsey Electronics FT146 combines ease of use with professional-grade features, making it an excellent choice for anyone looking to explore FM broadcasting. Whether for personal projects, educational purposes, or small business promotions, the FT146 delivers reliable performance and adaptability in a compact package.
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