❒8. Move your meter probe over to TP2, key the transmitter and adjust L5 and L11 for maximum negative reading. Once again, go back and forth between the two coils. You should get a reading of at least -120 mV. It is very important to tune for the best peak as this will ensure proper transmitter operation.

❒9. You should now be able to see RF power at the output antenna jack, J1. Adjust capacitor C12 for maximum RF power output.

❒10. Slightly spread or compress coils L3 and L4 to maximize output power. Power should be at least 4 watts with a 12 volt power source.

❒11. While speaking into the microphone, slowly rotate modulation control R13 clockwise for best sounding modulation. Ideally, a two-way radio service monitor should be used to adjust this control.

❒12. If a frequency counter or service monitor is available, adjust capacitor C43 for exactly 146.520 MHz. If you do not have such equipment, use a receiver with a center tune meter.

This completes the alignment of your FT146. The PC board should be mounted into a protective enclosure to guard against accidental contact. The Ramsey CFT case set provides an ideal, perfectly sized and matched case for your FT146. Study the following sections regarding the DC power supply and RF power indication, and operate your transmitter in accord with good amateur radio practice.

YOUR POWER SUPPLY AND RF OUTPUT POWER

For optimum performance, one or two volts of extra DC supply power can make quite a difference in any transmitter. For example, two lantern batteries in series, or 8 "D cells" will obviously provide "about 12 volts" with sufficient current capability for casual operating. For maximum RF output power, use a supply of 13 to 14 volts DC. The easiest method is to place two fresh "D cells" in series with your power source, if a full 13.6-15 volts DC is not available. A word of caution concerning wall plug style AC adapter power supplies: They are not suitable for operation of your transmitter due to their poor regulation, AC ripple content and RFI suseptibility.

If your supply voltage is in the 11-12 volt range, you can expect a 600 to 800 ma current flow and about 4 watts of the RF output power. With a solid 13 to 14 volt supply, you can expect about 1 amp current draw and up to 5 or 6 watts of RF output power.

VERIFYING TRANSMITTER RF OUTPUT

The most important thing to know is whether your transmitter is delivering some measurable and reassuring level of RF power to the antenna. The sound of the

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Ramsey Electronics FT146 manual Your Power Supply and RF Output Power, Verifying Transmitter RF Output
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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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