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250W Professional FM Radio Transmitter

STEREO WITH AUDIO PROCESSING OPTION
RDS OPTION
12VDC, 48VDC or 90-260VAC OPTION
USB 192 KHz 24 bit OPTION
INCLUDES SHIPPING
5 YEAR WARRANTY
EXCEEDS CE/FCC TECHNICAL SPECIFICATION

5 YEARS
LIMITED WARRANTY MORE INFORMATION

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.

Which Version Do You Need?

These are the two main versions of this transmitter:

◼ Stereo with RDS and Audio Processing Version

◼ MPX Version

These two versions cover 90% of all customer requirements. Other custom versions are available such as stereo only, no RDS, no processing etc. which we can also make if that's what you require.

You will find these two main versions shown in detail in the two following sections with descriptions of what they do and how they work. You should also see the price, INCLUDING delivery, to your country.

If you are still unsure, you are always welcome to contact us at em: info@aareff.com or ws: +1 829 6980733 and we're more than happy to advise you.

Stereo, RDS and Audio Processing Version

If you are not sure which version you want, then you definitely need this version. It is perfect for beginners because it adjusts the audio levels automatically and keeps the 250 watt transmitter within the legal specifications required by the state regulator.

This version is also ideal for professionals who just don't need the all the hassle. This is because it includes everything in one enclosure. The audio processing keeps the audio level 'LOUD', but not too loud whereby it causes over deviation and contravenes your permit. The trick is to get the sound as loud as possible so you can compete with the other stations on the dial, but at the same time keeping your signal legal. This is a tricky balance to maintain, but this version in stereo with our internal audio processers does exactly this.

250W Professional FM Radio Transmitter Stereo Audio and Processing

In addition, this version INCLUDES RDS. This allows everybody to see your station name and more scrolling across the car radio display.

The RDS is not just ordinary RDS, it is fully programmable dynamic RDS. This means the transmitter can be connected to a PC by a USB cable. The transmitters RDS circuit will pick the Artist and Song name from any folder on the PC disk drive. This folder is easy to set up in the DJ playout software, like Zara Studio etc. You can find more information about this in the Aareff RDS User Manual.

MPX Input

We have this version available for Users with experience that prefer straight raw MPX input.

Low frequency audio response is the holy grail for multiband audio processors, they need it.

As you can see from the image, the 160Hz square wave is very square with no tilting making it perfect for use with Orban, Inovonics, Omnia, Stereo Tool and other commercial audio processors.

250W Professional FM Radio Transmitter MPX 160Hz Tilt Test with MPX Tool

12V and 48V DC Option

The regular version of this unit is 90 to 260V AC. However we can also manufacture it for 12V or 48V DC. To the best of our knowledge, in the entire world, Only We Make 12V DC FM Broadcasting Transmitters and Amplifiers up to RF Power Outputs of 250W.

Applications include mobile setups where only a car or vehicle battery is available. We have a perfect Magnetic Mount FM Antenna for mobile setups. Also fixed installations with connection to solar battery systems of 12V and 48V DC

We default ship the AC version. If you want the 12 or 48V DC version, it's important you notify us by email when you make your order.

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.

    • SINGLE DIPOLE
    • 4.8dBi 2 DIPOLES
    • 7.8dBi 4 DIPOLES
    • 10.8dBi 8 DIPOLES
    • 4.8dBi 5/8 ANTENNA
    • -0.8dBi CIRC. DIPOLE
    • Folded 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.

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.

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

User Manual

RF Specification

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

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	N-Female
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 Ratio	80dB	65dB
Frequency Response	30Hz-76KHz	30Hz-15KHz
Audio Distortion	0.2% THD Max	0.2% 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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