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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
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LIMITED WARRANTY |
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.
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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 Version
This is for expert users who want to provide the MPX signal from an external source.
The PLL is slow locking, this is good as it maintains low frequency performance down to just a few Hertz. This low frequency response is heaven for processors.
The baseband MPX audio input has virtually no tilt whatsoever on the low bass frequencies making it perfect for use with multiband processors such as Orban, Invonics, Stereo Tool, Omnia etc. Check the image of the test we made in MpxTool.
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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.
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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.
Frequency, Power and Deviation
The frequency and power level is easy to change, but not so easy that somebody with no experience can just press a button on the front, that would be too easy and dangerous. We reached a compromise with this, we placed these controls on the underside of the unit. To get to them, just slide the unit out of the rack, flip it over and the little dip switches will allow you to change the frequency and a trim pots for the power and deviation level.
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
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 |
