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User Manual 30 Watt Band II VHF FM Broadcasting Amplifier

30 Watt FM Broadcasting Power Amplifier


i. The various pieces of equipment in this document are only for use permanently at a pre-defined location with a license or authorisation from the radio spectrum regulator in your country or EU member state.

ii. The installer must have competent RF engineering skills at their disposal, be EMC aware and understand radio frequency systems. The final installation should be in accordance with the site engineering document at https://www.aareff.com/ETR132.pdf The radio station management must assign a responsible person to the transmission equipment and installation.


1 30W FM Power Amplifier
1 IEC AC power cord
1 BNC to BNC 50 ohm Cable
1 90 Watt External Switch Mode 90-260V AC / 15V DC Power Supply


This product complies with EMC directive of the European Union. To meet this directive the user or installer must follow the wiring instructions in this user manual

This equipment is not intended for installation by an unqualified end user, the installer must have competent RF engineering skills and EMC knowledge at their disposal. The whole transmission system, including the antenna system, exciter and audio limiting, should be installed in accordance with document ETR132, a copy of this is available at https://www.aareff.com/ETR132.pdf


DO NOT plug in the power cord at this stage

A) Antenna

Incorrect antenna can cause RF burns and levels of RF exposure above the recommended limits for personnel

Ideally the antenna for this power amplifier should be at least 2 dipoles stacked and phased, a 5/8 type or other antenna with similar gain or more to the horizon. It should be ideally mounted 20 meters high and clear of any surrounding objects to get maximum range and more importantly to reduce risk of radio frequency radiation to personnel. When mounted at 20 meters in height off ground and using 30 watts of transmitter power, power flux density measurements made at ground level directly under the antennas described above show less than 1 W/m2. Several European countries use a value for the power flux density of 10 W/m2 as a basis for considering whether or not an area is safe. The issue of radio frequency radiation limits is a contentious one and work in this field is continuing worldwide.

UNDER NO CIRCUMSTANCES should the antenna be mounted and used at ground level or within a few meters of personnel.

A tuned antenna that presents 50 ohms with a 50 ohm coaxial cable should be used. This should give a return loss ideally of 16dB (SWR 1.4) or better at the operating frequency. The RF plug should be N type male.

Plug the antenna cable into the amplifier N type female connector. Make sure this is tight as poor and loose connections can cause RF burns to personnel, severe noise to the transmission and excessive RF bandwidth.

B) Amplifier Driver / Exciter

The Driver / Exciter needs to be compliant and set to the correct frequency BEFORE the amplifier is powered by AC Mains

Under NO CIRCUMSTANCES should the amplifier be connected to a Driver / Exciter where the RF output performance and specification is unknown. Such action could be cause serious disturbance to the electromagnetic spectrum and in extreme cases dangerous interference to air navigation and emergency services.

The amplifier requires a suitable driver / exciter with audio limiting and an RF output of between 900mW and 1400mW (MAX) when loaded with 50 ohms. This must also be equivalent, better or meet the specifications shown in European Standard ETS 300 384.

Connect the Driver / Exciter to the power amplifier using the 1m /3ft BNC to BNC RF cable, but DO NOT CONNECT THE AC POWER CORD TO THE AMPLIFIER YET

Before powering up the amplifier the frequency of the Driver / Exciter should be set and checked. If the AC mains is not connected to the power amplifier, it is safe to use the power amplifier BNC input as a dummy load for the Driver / Exciter. At this stage, if possible, it would also be advisable to check the deviation and that the audio of the Driver / Exciter is correct.

C) Powering Up

When you are absoulty sure and you have doubled checked the Driver / Exciter is operating correctly and the antenna is installed and connected correctly, then power up the 30W amplifier by connecting the AC power cord to it.

If you are using a transmitter driver supplied by another manufacturer, compliance cannot be guaranteed. On completion of the installation it is necessary that the engineer checks the RF output of the power amplifier for compliance.


A) Normal Conditions

You should hear the cooling fan, it's quite noisy. The fan draws air into the back and exits the warm air through front panel. It is important to keep these vents clear. If you cannot hear the fan turning, then shut the amplifier down by removing the AC mains immediately. The front meter should illuminate in BLUE

B) Indication Power LED

The front panel Power Meter should indicate the power or the the OUTPUT POWER LED should illuminate at the same brightness as the DC POWER LED. This shows the power being sent out of the output socket to the antenna.

If the Power Meter is showing much higher than 30W or the OUTPUT POWER LED is brighter than the DC POWER LED, then it is possible that there is a problem with the antenna cable, connectors or the installation of the antenna, this should be thoroughly checked before proceeding any further.

If the Power Meter is showing much lower than 30W or OUTPUT POWER LED is dimmer than the DC POWER LED, then it is possible that there is a problem with the RF connecting cable between the 1W driver and the amplifier, this should be checked before proceeding any further. It is also possible that there is a problem with the antenna cable, connectors or the installation of the antenna, this should also be thoroughly checked before proceeding any further.

C) Power Control

It is possible to reduce the power by reducing the Driver / Exciter if 30W is too much for your application. If you cannot reduce the power of the Driver / Exciter then there is a power control inside the amplifier. If you need to use this, please contact us for advice.


The only maintenance the amplifier needs is some periodic cleaning. Following a number of weeks of continuous 24/7 use (specified below), the amplifier should be shut down and disconnected. A technician or engineer needs to take of the top lid by removing the self tapper screws. Using a soft new and clean paint brush with a vacuum clean hose, the dust should be gently brushed and sucked away from all areas inside. Pay particular attention to the actual fans at the rear and the fan vent at front.

The table below shows the reccomended number of weeks cleaning should be done for some typical environmental areas.


Do not adjust any factory set internal controls.

Under NO CIRCUMSTANCES should any adjustments be made to the internal controls. Such adjustments could damage the unit and invalidate the warranty and also cause serious interference to other users of the electromagnetic spectrum.


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

RF and AF Parameters

Power Output Adj. Adj. 1 - 30 Watts into 50 ohms
Freq Range 87.5 to 108 MHz
Spurious Emissions Less than -75 dB ref to carrier
Harmonic Emissions Less than -70 dB ref to carrier
Residual AM Less than 0.5 %
Synchronous AM Less than 0.5 %
RF Output Connector N type Female
RF Ruggedness Any VSWR, phase, length of time
Operating Temp -20 to +40 Deg C

AC Mains Parameters

Model Meanwell GS90A15
Input Voltage 90 ~ 264VAC 127 ~ 370VDC
Input Power 50-60W input for 30W RF OUT with RF SWR < 1.5
Power Factor 0.95/230VAC 0.98/115VAC at full load
Working Humidity 20 ~ 90% RH non-condensing
Safety Standards UL60950-1, TUV EN60950-1 Approved
EMC Conduction & RadiationCompliance to EN55022 (CISPR22) Class B
EMC Harmonic Current Compliance to EN61000-3-2,-3
EMC Immunity Compliance to EN61000-4-2,3,4,5,6,8,11; ENV50204, Light industry level, criteria A

This amplifier is available with the AC power supply or without as a DC Version. If you are using the DC version, the external AC power you use should be CE Marked, have an output of 15V DC with no more than 100mV of ripple and capable of delivering 4 amps continuously. If you have the AC version with the power supply Aareff supplied, the following parameters apply.


Aareff Systems Limited can only guarantee compliance with ETS 300384 European Telecommunications Harmonised Standard and FCC Technical Requirements 47 CFR Chapter I part 73 when used with:

  1. A driver / exciter supplied and tested by Aareff Systems Limited.
  2. An audio compressor limiter supplied and tested by Aareff Systems Limited.
  3. The AC power supply is supplied and tested by Aareff.

Equipment compliance is perfectly possible and normal using equipment in conjunction from other manufacturers, but since this is beyond the control of Aareff Systems Limited, Aareff Systems Limited cannot ultimatly guarantee the compliance.

European Union

We hereby declare that this equipment complies with;

United States

This equipment has not been independently tested by an FCC recognised listed laboratory and for this reason it is not classified as certified. The following list are the technical requirements for the whole transmission system including this equipment and other equipment we may not supply. We hereby declare and verify that this equipment when used with a compliant audio compressor limiter and driver / exciter complies with the following FCC technical requirements

47 CFR Chapter I Federal Communications Commission parts:


We sell this equipment to professionals and organizations in good faith it will be used correctly and legally. Nearly every country in the world require licensing for this type of equipment. It is the customer’s responsibility to check relevant laws, directives, regulations and licensing requirements before installing or putting this product into service with an antenna system. You, the customer or user agree to defend, indemnify and hold harmless Aareff Systems Limited, it’s employees and agents, from and against any claims, actions or demands, including without limitation legal and accounting fees, alleging or resulting from improper or unlawful use of this equipment.


All components used in this apparatus are RoHS compliant and do not contain above the specified limits in any of the following restricted substances:


This apparatus must NOT be disposed of with other domestic waste.

We are fully committed to maintaining our responsibilities to the environment. Owners of apparatus that has reached the end of it's useful life can return it to us for recycling, recondition, reuse or proper disposal. You will be required to pay lowest cost postal service available to ship the apparatus to us. Before shipping please contact us for more important information.


ALL RIGHTS RESERVED. Aareff is a trademark of Aareff Transmission Systems. All contents of this document including, but not limited to the images, logos, text, illustrations are protected by copyrights, trademarks and other intellectual property rights which are owned and controlled by Aareff Transmission Systems or by other parties that have licensed their material to Aareff Transmission Systems. This document in part or whole may not be copied, reproduced, republished, uploaded, posted or distributed in any way, including by e-mail, ftp or any other electronic means

Every care has been taken in the preparation of this document, errors in content, typographical or otherwise, may have occurred. If you have comments concerning its accuracy, please contact Aareff Systems Limited (UK)


Inc. Delivery to UNITED STATES

US$ 510.02

POWER AMPLIFIER FM 1W IN 30W OUT 19 INCH 12-15V DC OR 90-260V AC (30wnta19p)
US$ 517.51


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