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20W Professional FM Radio Transmitter

SUPER SILENT
STEREO WITH AUDIO PROCESSING OPTION
RDS OPTION
12VDC 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 popular choice in Nigeria for campus type university radios that are licensed by the state for 20 watts. Using this 20 watt transmitter with our 4 way stacked dipole is a popular choice producing a total EIRP of approximately 80 watts.

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 20 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.

20W 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 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.

20W Professional FM Radio Transmitter MPX 160Hz Tilt Test with MPX Tool

Antennas

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
    • FOLDED DIPOLE

Our system package the 20W EIRP system includes this transmitter with a dipole antenna and very low loss LMR400 cable to give you a full system that will comply with the regulations of the European Union and most other countries in the world.

Reliability

Like all our products, we over engineer them, this is no exception. This uses a 45 watt transistor, for 20 watts output. basically you can throw any amount of reflected power at this unit and it will laugh in the face of it. Basically this transmitter, is not super, not ultra, it's HYPER reliable

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

User Manual

RF Specification

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

Power Output	Adj. 1-20 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	40W for 20W 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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