250 Watt Professional FM Broadcast Transmitter




250W FM Stereo Broadcasting Transmitter with Audio Processing Front Panel


Suitability

This is a beautiful machine, recently upgraded to 250 watts for the 200 watt version we sold for over a decade. There are lot of these units going strong in the world working 24/7 without a hiccup. The internal 250 watt amplifier blocks will operate with ease at full power 24 hours a day non stop in any country and with any AC voltage in the world. The front panel has a neat little meter panel lit up in blue to indicate forward and reflected power.

VSWR Protection

The RF output power of the amplifier automatically folds back, very fast to a safe level when there is fault condition of poor SWR and return loss of any level for any duration of time. When the fault clears the amplifier restores to full power.

Temperature Protection

This unit is designed with high reliability in mind to work in hot countries close to the equator. The cooling system incorporates at the back three 60 mm fans and at the front one 80mm fan to keep the heatsinks in this unit cool to touch by hand. Many of these units are operational for years in Nigeria without any issues. If this is not enough, if any of the fans were to fail, and let's face it and be honest, that could happen after a few years of use, the internal temperature sensor will reduce the amplifier power down to a safe level to keep the temperature in check until the fan has been replaced by a new one.

Construction

The enclosure is made in strong 16 gauge steel, powder coated and baked in satin black. This leaves a tough, durable surface that will never rot or corrode and be cleaned to shine for decades. The front panel is 19 inch across and 2U (3.5 inch) high with a depth of 12 inches, so it will fit with ease into a standard rack. It is very strong and difficult to damage even under extreme handling.

Settings

If you are qualified or understand broadcast radio specifications and parameters you can set the frequency and deviation yourself. This is easily done by flipping over the unit and adjusting the little dip switches on the underside panel. More information on this in the User Manual, you can find a link to this below.



Rear Panel of 250W FM Stereo Broadcasting Transmitter with Audio Processing


Five Years! Warranty
5 YEARS LIMITED WARRANTY
more Information

Which Version Do You Need?

The stereo version with audio processing and limiting is available or the straight raw composite MPX version. If you're not sure which version you need, then it's a high probability that need the stereo version with audio processing and limiting. In any case the stereo version has the option of MPX input, it can be used for both. If you wish to connect the unit to external processing such as Optimod, Inovonics, Breakaway, StereoTool etc you should use the MPX version More Information HERE.

STEREO VERSION WITH AUDIO PROCESSING
User Manual

MPX / COMPOSITE INPUT (NO PROCESSING)
User Manual





250W FM MPX Broadcasting Transmitter Front Panel


Antennas

250 Watts with a high performance well installed antenna is a typical set up for a local radio station for a big town or small city. In rural areas up to 45 miles range is possible.

On delivery the equipment is ready to plug in and use with any suitable 50 ohm antenna system such as our:
SINGLE DIPOLE
4.8dBi 2 DIPOLES
7.8dBi 4 DIPOLES
10.8dBi 8 DIPOLES
4.8dBi 5/8 ANTENNA
-0.8dBi CIRC. DIPOLE


Our 500W EIRP package includes this transmitter complete with antennas and cables ready to go. It is a full system that complies with the regulations of the European Union and most other countries in the world.

Do You Have A Question?


Compliance

The stereo version with audio processing and limiting meets all the regulatory standards required out of the box and pre configured. In fact if you send us a copy of your permit and it's conditions, we will set it up exactly to the specification. This equipment complies with EU/CE harmonised standards and FCC technical requirements for FM broadcasting. More information HERE

All stated measurements were made at 220VAC at 27 Degrees Celsius ambient temperature unless stated.

RF Specification

Power Output Adj. 1-250 Watts into 50 ohms
Spurious Emissions Less than -75 dB ref to carrier
Harmonic Emissions Less than -70 dB ref to carrier
Freq Stability +/- 1 KHz max. typ. +/-300 Hz
Deviation Sensitivity Stability +/-2 % max
Freq Fine Adj > +/- 1000 Hz
Freq Range 87.5 to 108 MHz in 100 KHz steps
Out of Lock RF Muting Less than -70 dB ref to carrier
Residual AM Less than 0.5 %
Synchronous AM Less than 0.5 %
RF Ruggedness Any VSWR phase or length of time
Output Connector
Operating Temp -20 to +40 Deg C

AF Specification

Pre-emphasis (50 uS/ 75 uS/ None) Selectable
Audio Input Connector Phono/ RCA type unbalanced sockets
Audio Input Sensitivity +4 dBu for +/- 75 KHz dev.

Version MPX Stereo and Audio Processor
Signal To Noise Ratio80dB 65dB
Frequency Response 30Hz-76KHz 30Hz-15KHz
Audio Distortion 0.2% THD Max0.2% THD Max (at MPX section)

AC Specification

Input Voltage 90-264 V AC 135-370 V DC 47-63 Hz
Input Power 500W for 250W RF OUT with RF SWR less than 1.5
Working Humidity 20-90% RH non-condensing
Safety Standards UL60950-1 TUV EN60950-1 BSMI CNS14336 CCC GB4943 J60950-1 approved
EMC Emission Compliance to EN55022 class B EN61000-3-2 3 FCC PART 15 / CISPR22 class B CNS13438 class B GB17625.1
EMC Immunity Compliance to EN61000-4-2 3 4 5 6 8 11 light industry level criteria A
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