coil drastically whenever it is inserted into the coil. You may use a metal hex key if you are aware of this effect and are willing to remove the hex key from the coil after each adjustment. Although not recommended, with a little patience and sandpaper, a useable tool may be formed from a piece of wood or plastic rod. If you do make your own tool, be very careful to fully engage the slug because they are very brittle and any wedging or skewed turning will break it!

❒3. Small flat blade screwdriver or alignment tool for trimmer capacitors C12, C43, and modulation pot R13.

❒4. A suitable 50 ohm dummy load.

❒5. Proper cable to connect from FT146 transmitter (RCA phono) to dummy load.

❒6. A 12 volt DC power source of at least 1 amp.

❒7. A digital multimeter.

With all the above set-up and handy, let's get testing!

❒1. Using your hex head tuning tool, back out the coil slugs in L9, L13, L5, L11 even with the top of their plastic coil form. If a slug binds, gently rock it back and forth till it loosens up. Be very careful not to crack the slug as they are brittle. Slowly rotate each slug clockwise into the coil form the indicated number of turns:

L9: 2 turns

L13: 3 turns

L5: 8 turns

L11: 4 turns

❒2. Rotate modulation control R13 fully counter-clockwise.

❒3. Apply 12 volts to the FT146 transmitter board. Its a good idea to fuse the power to the FT146, 1 to 2 amps will do.

❒4. Connect a proper 50 ohm dummy load to antenna connector J1. In a pinch, a light bulb may be used - see the section "Verifying Transmitter RF Power Output".

❒5. Plug the microphone into mike jack J2. If you have no microphone, you may at least "key" the transmitter by jumpering the "PTT" point behind DIN jack P1 to ground.

❒6. Hook your multimeter to TP1 and set the meter to the 200 mVDC, (0.2 VDC range).

❒7. Key the microphone and adjust L9 and L13 for maximum indication on TP1. No more than a turn or two is needed. You will have to go back and forth between these coils as they interact. You should get a reading of at least 50 mV.

FT146 • 19

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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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