Introduction

Two meter FM has been around for years, but never with the popularity that is enjoyed today. In the old days, hams snooped around the local two-way radio shop in search of an obsolete taxi cab or police radio. These radios were in the 150 - 174 MHz business band and were easily moved down into the ham two meter band. On the chance that a UHF 450 - 470 MHz radio was found, it was modified for the ham 440 band. Since there was no business band near the 220 MHz ham band, no radios were available for conversion - and that's why the 220 band never became popular!

Well, its been a long step from then to now, and not a pleasant one for ham radio. We've lost a portion of our 220 band and gave up our ham radio market to the Japanese. Gone are the radio mavens who could modify, in an evening, the old Motorolas, GEs and RCAs. Modern day hams don't use modified commercial radios, they operate rigs designed expressly for amateur use, and who can blame them? For a half a kilobuck (that's $500 in regular talk) you can get a full band synthesized 30 watt radio that looks like a fine piece of audio gear! Good deal but something is missing, and that's the pride in building, understanding and learning. You see it really doesn't take a whole lot of smarts to unpack a box that was last sealed somewhere in the Orient. Building your own rig is one of the most satisfying and rewarding experiences you can have - and that's what ham radio is all about! This little, easy to understand two meter FM transmitter is our attempt to provide the ham community with a simple, fun to build kit that you'll enjoy operating, especially when you tell the other operator that the rig here is home-brew.

Most Ramsey Electronics can be classified as "Skill Level 1" if we use the old Heathkit guidelines for ease of assembly. That means that our kits are intended to be successful for first-time kit builders. This FT146 FM Transmitter is best regarded as a "Skill Level 2" project, (or least Level 1.46!) and should not be taken lightly, even by experienced, licensed radio amateurs.

Still, this step-by-step manual is written with the beginner in mind, because we are well aware of the fascination Two Meters and its maze of repeaters holds, which means this could be your very first kit project. To be honest, we'd like to see first-time builders start out with an easier kit such as the Ramsey HR-40 forty meter all-mode receiver before assembling the FT146, but we are confident that you can construct the FT146 successfully if you follow this manual carefully and patiently.

Before beginning the project or even studying the circuit description, it's worthwhile to develop some prior respect for how much transmitter is packed onto the circuit board. The dozen semiconductor devices (diodes, transistors

FT146 • 4

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.