R V R Elettronica EDL300-FM FM Transmitter User Manual
- June 13, 2024
- R V R ELETTRONICA
Table of Contents
R V R Elettronica EDL300-FM FM Transmitter
Product Information – EDL300-FM
Introduction
The EDL300-FM is a dummy load produced by RVR Elettronica SpA to be used with FM transmitters with nominal power up to 300 W. Dummy loads are mainly used as laboratory test devices and are often included in redundant (1+1 or N+1) transmission systems, in which the output of the spare transmitter is normally connected to the dummy load for test purposes. The EDL300-FM is particularly suited for use in compact transmission systems, thanks to its small form- factor. The quadratic construction enables a simple installation.
Working Principle
The EDL300-FM is a 50Ω resistive load optimized to work in the audio FM band. The applied power is dissipated by four 50Ω power resistors connected in a series/parallel configuration to compensate for the parasitic capacitance of the resistors and obtain a return loss better than 26 dB on the whole 87.5 – 108 MHz band. The resistors are fixed on a metal heatsink, and three fans generate the airflow to let the heat pass to the environment.
External Description
The EDL300-FM features the following external components:
- Interlock connectors (BNC with inner normally grounded, floating in case of interlock)
- Input RF connector (N-type)
- VDE plug for mains supply (220 AC)
- Mains fuses for the fans (2A each)
Please ensure that the airflow grid is not covered to ensure proper functioning of the device.
Power Derating
The power that the EDL300-FM can continuously dissipate depends on the temperature of the environment. It is essential to link the transmitter to the interlock connectors of the EDL300-FM to avoid the risk of damaging it.
Technical Specifications
| Technical Characteristic | Description |
|---|---|
| Manufacturer | RVR Elettronica SpA (Italy) |
| Nominal Power | Up to 300 W |
| Load Resistance | 50Ω |
| Return Loss | Better than 26 dB on the whole 87.5 – 108 MHz band |
Product Images
Introduction
The EDL300-FM is a dummy load produced by RVR Elettronica SpA to be used with
FM transmitter with nominal power up to 300 W.
Dummy loads are mainly used as laboratory test devices and are often included
in redundant (1+1 or N+1) transmission systems, in which the output of the
spare transmitter is normally connected to the dummy load for test pourpouses.
The EDL300-FM is particularily suited for the use in compact transmission
systems, thanks to its small form-factor. The quadratic construction enables a
simple installation.
Working Principle
Simply speaking, the EDL300-FM is just a 50 Ω resistive load, optimized to
work in the audio FM band.
The applied power is dissipated by four 50 Ω power resistors connected in a
series/ parallel configuration (see the enclosed schematic), able to
compensate the parasitic capacitance of the resistors, to obtain a return loss
better than 26 dB on the whole 87.5 – 108 MHz band.
The resistors are fixed on a metal heatsink, and three fans generate the air
flow to let the heat pass to the environment.
The fans are activated by a thermal bimetallic switch, that is normally opened
and will close as soon as the heatsink’s temperature surpasses 55 °C.
WARNING: Always connect the power source (the transmitter) using the interlock connectors, to avoid the possibility of an excessive temperature rise that could damage the dummy load and even the transmitter itself!
External Description
The following drawing shows the dummy load.
WARNING: don’t cover the airflow grid, to ensure proper functioning of the device.
- Interlock connectors. BNC with inner normally grounded, floating in case of interlock
- Input RF connector RF (N-type)
- VDE plug for mains supply (220 AC)
- Mains fuses for the fans (2A each)
Power Derating
The power that the EDL300-FM can continuosly dissipate depends on the
temperature of the environment.
Since the dummy load can work at a temperature up to 90 °C before the
protection device is triggered, figure 2 gives the acceptable working area of
the device.
WARNING: Please remember that it is essential to link the transmitter to the interlock connectors of the EDL300-FM, to avoid the risk of damaging it.
Technical characteristics
- Frequency band 87.5 – 108.0 MHz
- Nominal power at 40°C 300 W
- Power derating at t > 40 °C 12 W/°C
- Return loss > 26 dB
- Power Supply 230V ac + / – 10%
- Fuse 2 A
- Size (L x H x D) 320 x 85 x 375 mm
- Weight 12 kg
Images
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