User Manual and Installation of 4000W (4KW) EIRP System


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 The radio station management must assign a responsible person to the transmission equipment and installation.


1 Stereo coder audio limiter / 1 watt FM driver exciter 15V DC (ALSCB & 1WPLLB)
1 800W FM power amplifier
1 DC to DC Lead (DC connections from ALSCB to 1WPLLB to distribution amplifier)
2 IEC AC power cord
1 MPX audio lead (audio connection from ALSCB to 1WPLLB)
1 BNC to BNC lead (rf connection from 1WPLLB to Distribution Amplifier to a 800WNTAP)
1 15V DC switch mode AC power supply (1W)
1 Rack Rails


4A1/2 wave, base, 25mm dia. main radiator, 22mm dia. top adjust tube and tube clamp
4B38mm x 800mm boom tube
4CBoom to mast/ tower mounting clamp. Each set includes, 1 x 100mm square 3.2mm thick clamping plate, 4 x 38mm U bolts with M8 threads, 8 x M8 spring washers, 8 x M8 plain washers and 8 x M8 nuts
4DAntenna base to boom U bolts clamp assemblies. Each set includes 2 x 38mm U bolts with M8 threads, 2 x 38mm tube clamp, 4 x M8 spring washers, 4 x M8 plain washers and 4 x M8 nuts
4EBottom tuning bar
4FTop tuning bar
4GTuning bar M6 screw, 1 aluminium sleeve, 2 M6 washers and 1 M6 nut
4HTuning bar M6 screws and washers

3 Splitter Boxes
4 Combo cable LMR400 (2.93 mt BLUE 90ş plug) and RG11 (0.63 mt) GREEN plug, total length 3.56 mt
2 Combo cable LMR400 (2.93 mt BLUE STRAIGHT plug) and RG11 (0.63 mt) GREEN plug, total length 3.56 mt
1 30m roll of LMR400 antenna cable

IMPORTANT! PLEASE READ, we know it's boring, but if you want your system to work correctly, safely and legally, it is necessary.

The antenna is the most important part of the transmission system and must be correctly installed before proceeding further and before any other transmission equipment is connected.

Ideally this antenna should be mounted at least 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 least 20 meters in height off ground and using 800 watts of transmitter power, power flux density measurements made at ground level directly under the antenna 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.



When writing this manual there was no EU directive regarding the EMC compatibility of Band II VHF broadcast antennas, however in our view there are some potential EMC compatibility issues that need to be addressed when installing this antenna system. On completion of the antenna installation check;



Using the following items to assemble the four antenna base sections with the tuning loops as shown in the picture below.

1 x (A) 0.5λ (half wave) radiator and base
2 x (D) Antenna base to boom U bolts clamp assemblies
1 x (F) Top tuning bar
1 x (E) Bottom tuning bar
2 x (H) M6 screws and 2 washers
1 x (G) Tuning bar M6 screw, 1 x aluminium sleeve, 2 x M6 washers and 1 x M6 nut

1. The tuning loop, bar and aluminium sleeve form an half turn inductor. The operating frequency determines the position of the aluminium sleeve. Put the aluminium sleeve in one of the six positions shown in picture for the frequency that you want. This sleeve will be carrying a huge RF current, make sure it is tight and firm. The tuning loop and bar should also be screwed tight to the Teflon section with the two M6 screws and washers. This is shown in the pictures.

2. The bottom tuning bar should also be clamped tight to the back plate of the base and the 38mm x 800mm boom tube using the U bolt clamp assemblies. Again as shown in the picture below.


Pick the frequency (MHz) from the table that is the closest to frequency you need to use. For example if you needed 91.3 MHz, then you would pick 91 MHz, this is the closest.

1. Adjust the radiator to length shown in metres for 0.5λ (wavelength). Use a metric tape measure to measure the length from the (IMPORTANT) top plate of the base section to the end of the top tube. Slide the top radiator tube inside the bottom large radiator tube until the correct length is reached. At the correct length tighten the circular screw clip to secure the two tubes in place. Make sure the clip is tight and the tubes don't move. DOUBLE check the length again from the top plate of the base section to the end of the top tube. If this length is not correct, the antenna will not radiate correctly and there'll be high reflected power and SWR.

2. Make the distance / spacing between the booms to 2.8 mt. This is not a critical measurement and only needs to be accurate to +/- 2 or 3 cm. This spacing optimises the complete antenna system to give maximum gain to the horizon.

FREQ. MHz0.5λ Radiator Length
87 MHz1.64 mt
88 MHz1.62 mt
89 MHz1.60 mt
90 MHz1.58 mt
91 MHz1.57 mt
92 MHz1.55 mt
93 MHz1.53 mt
94 MHz1.52 mt
95 MHz1.50 mt
96 MHz1.48 mt
97 MHz1.47 mt

FREQ. MHz0.5λ Radiator Length
98 MHz1.45 mt
99 MHz1.44 mt
100 MHz1.43 mt
101 MHz1.41 mt
102 MHz1.40 mt
103 MHz1.38 mt
104 MHz1.37 mt
105 MHz1.36 mt
106 MHz1.34 mt
107 MHz1.33 mt
108 MHz1.32 mt


If it all possible you should try and assemble the whole four way half wave antenna system horizontally on the ground to a long 38mm diameter tube. This is much easier and safer. Then when it's all complete, hoist the complete 38mm tube with all the antennas and booms fastened to it, up to the tower. Then clamp by whatever means you have (depends on the tower construction) the whole 38mm tube and antenna assembly vertical to the tower.

1. MOUNT THE HALF WAVE ANTENNAS, all four antennas and booms to the mast using C the boom to mast / tower mounting clamp assemblies. It is IMPORTANT for correct operation that the dimensions on the diagram are followed as closely as possible, all antennas must be directly above each other with 2.8 mt between the booms in order for the system to work properly and give maximum gain to the horizon. Do not connect any cables yet, just make sure the antennas are lined up correctly, tight and rigid

2. MOUNT THE SPLITTER BOXES to the mast to the dimensions shown in the diagram. Splitter box 1 is the top box and should be mounted on the mast about 60cm (0.6mt) below the boom of antenna 1. Splitter box 2 is the middle box and should be mounted on the mast about 60cm (0.6mt) below the boom of antenna 2. Splitter box 3 is the bottom box and should be mounted on the mast about 60cm (0.6mt) below the boom of antenna 3.

3. CONNECT THE 90ş COMBO CABLES Using the four combo cables of LMR400 with 90ş blue plugs on one end and green plugs on the other ends, connect the green ends to the outer sockets of the splitter box 1 at the top and splitter box 3 at the bottom. Then connect the blue 90ş ends to each of the four half wave antennas. IMPORTANT! DO NOT CUT BACK, ADD OR CHANGE ANY OF THE COMBO CABLE LENGTHS. To get maximum radiation to the horizon it is important that the signal to each antenna arrives at exactly the same time, this can only happen if the cables are exactly the same length.

4. CONNECT THE STRAIGHT COMBO CABLES Using the two combo cables of LMR400 with STRAIGHT blue plugs, connect the blue plugs to the centre sockets of splitter box 1 at the top and splitter box 3 at the bottom. Then connect the green end plugs to outer sockets of the splitter box 2. Again, IMPORTANT! DO NOT CUT BACK, ADD OR CHANGE THE LONG ANTENNA CABLE LENGTHS. To get maximum radiation to the horizon it is important that the signal to each antenna arrives at exactly the same time, this can only happen if the cables are exactly the same length.

5. CONNECT THE MAIN FEED CABLE Using the long 30 mt LMR400 cable (or longer if you specially ordered extra) connect one end to the centre socket of splitter box 2 in the middle. Take the other end of the cable down to the location of where you transmitter or amplifier is located.

6. MAKE SURE THE CONNECTORS ARE SCREWED PROPERLY AND TIGHT. Wrap PVC or self amalgamating tape tightly around and all over the connectors to make them water resistant.

7. Securely fix the cables using PVC tape or large cable ties to the mast as shown in the diagram. Make sure the cables are not going to flap around in the wind. Once again, do not cut back any excess cable. To make the cabling look tidy, it is okay to coil the cable.

8. Make sure that all fixings, brackets and clamps are tight and are not going to work loose over time with wind.

9. On completion of the antenna installation you should have the long LMR400 cable coming down from the antenna assembly ready to plug into the large RF power amplifier or transmitter.






When this system was ordered, if a specific frequency was given during the order process, then the system will have been set and factory tested at this frequency. If not, or you need to change the frequency or power level please refer to the user manual for 1W PLL FM STEREO DRIVER / EXCITER WITH AUDIO PROCESSING at

1. Use the supplied M6 screws, nuts, washers and rack rail bars to clamp the Driver (1WPLLB and ALSCB) and the 800W power amplifier together as shown in the picture. The power amplifier is much heavier, so these should be at the bottom. The Driver is light and will suspend in the air and does not need any support at the back.

Alternatively you can mount the units in a professional 19 inch enclosure and integrate the units with other equipment that you have.

2. Connect the 800 WATT RF OUTPUT from the power amplifier to the long LMR400 cable coming down from the antenna assembly.

3. Using the 1m BNC to BNC leads supplied connect the 1 WATT RF INPUT from the power amplifier to the the 1 WATT RF OUTPUT from the 1WPLLB driver / exciter

4. Plug the small 15V DC switch mode AC power supply into the ALSCB DC INPUT. Connect the ALSCB DC AUX OUT to the 1WPLLB DC IN using the short black DC to DC Lead.

5. Using the MPX Audio Lead, connect ALSCB MPX OUTPUT to 1WPLLB MPX INPUT

6. Connect mains AC power to the 800W amplifier. The driver will lock after a few seconds and amplifiers should indicate power on the front panel meters. The switch on the front panel of the amplifier should be set to ‘FWD’.

7. Finally, provide an audio input to the ALSCB Stereo Generator and Limiters and you are "ON AIR".



Power Supply 90-260 VAC 50/60 Hz
Transmitter RF Power Output 800 Watts +/- 0.5 dB from -20 to +40 Deg C
Freq Stability Better than +/- 2 KHz from -20 to +40 Deg C +/- 300 Hz typ.
Freq Range 100 KHz steps from 87.5 to 108 MHz
Deviation Sensitivity Stability +/- 2 % max
Spurious Emissions Better than -75dB ref to carrier
Harmonic Emissions Better than -70dB ref to carrier
RF Bandwidth 200 KHz (+/-100 KHz @ -40 dB rtc)
Output Connectors N type 50 ohm
RF Ruggedness Any VSWR any phase any length of time
Audio Input Sensitivity 0 dBu 775 mV rms adjustable
Audio Inputs Connector Phono/ RCA socket
Audio S/N Ratio Better than 70 dB
Audio Freq Response 30 Hz to 15 KHz +/- 0.5 dB
Audio Distortion Better than 0.1 % at +/-75 KHz dev
Stereo Crosstalk 35 dB
Pre-emphasis 50 uS (75 uS USA) or None
Pilot Tone Freq 19 KHz
Pilot Tone Stability 0.2 Hz
Antenna Polarisation Vertical
Antenna Gain (0.9λ 2.8 mt spacing at 98 MHz) 6.6 dB + (Isotropic Gain) 2.1 dBi = 8.7 dBi
Antenna Cable Loss -1.2 dB 30m LMR400 foam cable
Antenna RF Power Output 4498 Watts EIRP +/- 0.5 dB (total system gain +7.5 dBi) from -20 to +40 Deg C using 30m of LMR400 foam antenna cable and the four half wave antennas supplied spaced at 0.9λ at 98 MHz


European Union

We hereby declare that this equipment complies with;
• ETS 300384 European Telecommunications Harmonised Standard when used with an audio compressor limiter supplied and tested by Aareff
• EN 301489-11 V1.3.1 (2006-05) EMC Electromagnetic Compatibility when used with 1 meter AC mains cord supplied. If the installation engineer needs to extend this cord, this and the audio input cable should be no more than 3 meters in length to remain in compliance with EMC directive.
• 2006/95/EC Directive (2006-12) LVD Low Voltage Directive.

Equipment compliance is possible using equipment from and in conjunction from other manufacturers, but since this is beyond the control of Aareff Systems, Aareff Systems cannot or be expected to guarantee compliance in this situation.

United States

The following list are the FCC technical requirements for FM broadcasting. We confirm and verify that this transmitter complies with the technical requirements.

47 CFR Chapter I Federal Communications Commission sections:
• 73.1560, 2.1046 RF Power
• 73.1545, 2.1055 Frequency Stability
• 73.317, 2.1049 (e)(3) Emission Limitation, Emission Mask
• 73.317, 2.1057, 2.1051 Emission Limits, Spurious Emissions at Antenna Terminal
• 73.317, 2.1057, 2.1053 Emission Limits, Field Strength of Spurious Emissions


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

• Lead
• Hexavalent Chromium
• Mercury
• Cadmium
• Polybrominated Biphenyls (PBB's)
• Polybrominated Diphenylethers (PBDE's)


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.


It is the customer's responsibility to check relevant laws, directives, regulations and licensing requirements before putting this product into service with an antenna system. You, the customer 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 product.


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)