FM Combiner Systems: Efficiently Combining Multiple Transmitters into a single Antenna.
An FM Combiner, or an FM Diplexer, is a passive device. It efficiently combines signals from multiple FM transmitters (typically 2-8) into a single coaxial cable and antenna system. Indeed, this eliminates the need for individual antenna setups for each transmitter, simplifies installation, and greatly reduces costs.
How Does it Work?
- Signal Combination: The combiner merges the output signals from all transmitters. It sends them to a single feeder and antenna system.
- Power Handling: The antenna design must also handle the combined power from all transmitters. For example, 6 x 5kW transmitters will generate approximately 30kW of total power.
- Frequency Separation: The most crucial factor is the frequency separation between each channel. Ideally, it should be 2 MHz to prevent interference. However, a separation of 800 kHz will be achievable with advanced multi-stage filtering. Narrower separations (e.g., 600 kHz) will lead to intermodulation and distortion, potentially degrading stereo quality.
Types of FM Combiners
- Starpoint Combiners: These joint filtered signals at a common point. They are simpler and more affordable but may introduce slight signal reflections, potentially affecting signal quality at higher frequencies.
- Constant Impedance Combiners: These utilise transformers to maintain a consistent impedance (usually 50 ohms) across the FM frequency band. This minimises reflections and also offers superior performance, especially for longer cable runs. However, they typically require a higher initial investment.
Choosing the Right Combiner
- Starpoint: Suitable for basic setups with short cable runs and a focus on cost-effectiveness.
- Constant Impedance: Recommended for longer cable runs and applications where signal quality is paramount.
Sky Technology: Your Trusted Partner!
At Sky Technologies, we collaborate with Jampro Antennas, a leading global combiners manufacturer. We provide the ideal solution for your needs, prioritising cost-effectiveness while ensuring good performance and reliability.
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Finally, please contact us for expert guidance and a customised solution for your FM broadcast needs. We are here to help you choose the best combiner for your unique needs.