The antenna is the most important part of the transmission system and must be correctly installed before proceeding further and before any transmission equipment is connected.
Under no circumstances should the antenna be mounted and used at ground level or within a few meters of personnel.
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 400 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.
You are responsible for selecting the correct antenna for your application, installing it properly and ensuring the system maintenance.
|1||A YELLOW Cycloid (square) dipole with boom, RF connector and gamma match bar, M6 screw, two washers, spring washer and nut.|
|1||B RED Cycloid (square) dipole with boom, RF connector and gamma match bar, M6 screw, two washers, spring washer and nut.|
|4||C Mast/Pole U-Clamps 28mm, 38mm or 52mm|
|1||D YELLOW Splitter cable LMR400 + 63cm RG11|
|1||E RED Splitter Cable LMR400 + 63cm RG11|
|2||F Mast fixing clamps with four M6 x 50mm screws, eight washers, four spring washers and four nuts with each clamp (shown in more detail below)|
|2||G RED Vertical radiator with M6 screw, plain washer and spring washer|
|2||H YELLOW Vertical radiator with M6 screw, plain washer and spring washer|
|1||J Splitter box with three N-female connectors|
F Mast Clamps
J Splitter Box
Following is a list of precautions to follow when installing the antenna if placement of antenna and cables is anywhere near power lines.
This antenna is intended for use with an FM broadcasting transmitter up to 800 watts at a permanently pre-defined location with a license or authorisation from the radio spectrum regulator of your country.
Using the parts marked F (Mast Clamps) assemble the mast clamp as shown in this photo.
Assemble the cycloid dipoles, RED and YELLOW, as shown in the photo. RED parts together and YELLOW parts together.
• Connect the GAMMA MATCH bar to the FEED POINT using the M4 screw and nut already there. Tighten the screws
• Fit the VERTICAL RADIATORS to the main body of the cycloid dipole using the M6 screws as shown in the photo below.
1. Mount the cycloid dipoles to the mast using the clamps provided, RED at the bottom and YELLOW at the top. It is IMPORTANT for correct operation that the dimensions on the diagram are followed as closely as possible, both cycloid dipoles must be directly above each other for the system to work properly and give the full tuned bandwidth of +/- 1.4 MHz (SWR <1.5).
2. Mount the splitter box with the three RF connectors using the tie wraps provided on the mast between the cycloid dipoles as shown on the diagram. The connectors on the splitter box should be facing down. This is because the body of the splitter box shelters, not fully, but a little, the connections from rain and water
3. Connect the main feeder cable from the transmitter to the CENTER connector of the splitter box.
4. Using D YELLOW splitter cable (LMR400 + 63cm RG11) connect the GREEN end to one of the OUTER connectors of the splitter box and E RED splitter cable (LMR400 + 63cm RG11) connect the GREEN end to the other OUTER connector on the splitter box. IT'S VERY IMPORTANT THAT THE GREEN (RG11) ENDS OF THE CABLES CONNECT TO THE OUTER CONNECTORS OF THE SPLITTER BOX or the antenna system will not work.
5. Using D YELLOW splitter cable (LMR400 + 63cm RG11) connect the end with LMR400 to the Top YELLOW cycloid dipole. Using E RED splitter cable (LMR400 + 63cm RG11) connect the end with LMR400 to the bottom RED cycloid dipole. There will be excess cable, simply coil this neatly and tape or tie it to the mast (DO NOT CUT IT BACK AND REFIT THE PLUG). The cables marked with YELLOW and RED of each cycloid dipole are critical phased lengths and must never be altered in length.
6. Wrap PVC or Self Amalgamating tape tightly around and all over the plugs on the Splitter Box to waterproof them.
7. Securely fix the cables using PVC tape or large cable ties to the mast as shown in the diagram opposite. Make sure the cables are not going to flap around in the wind.
8. Make sure that all fixings are tight and are not going to work loose over time with wind.
|Gain||3.62dBi / 1.47dBd at 98MHz|
|Freq Range||87.5 to 108 MHz (Factory Tuned)|
|Max Power||800 Watts|
|Construction||Aluminium, Teflon, Resin and Stainless Steel|
|Connector||N type Female|
|Input Z||50 ohm unbalanced|
|Polarization||Circular / Mixed|
|Vertical Beamwidth||32 Degrees|
When writing this manual there was no EU directive regarding the EMC (Electro Magnetic 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;
1. All the cables entering the connectors are tight and properly crimped or soldered
2. All the connectors are screwed in tight and sound.
3. PVC insulation tape and/or self amalgamating tape are wrapped around all the connectors to stop water entering the connector and the inside of the body of the cable.
If any cables are loose or there are bad connections this can cause some non-linear resistance, diode action or some small arcing. When this happens it creates EMC disturbance (arcing and crackling sound) across a wide frequency spectrum.
Because antennas are passive devices maintenance requirements are low, however don’t accept low as being none existent, some periodic inspections are required.
Always following a heavy storm or extreme weather condition an inspection should be done and as shown in the table below.
|WEEKS||Building Roof||Light Duty Tower||Heavy Duty Tower|
We sell this equipment to professionals and organizations in good faith it will be used correctly and legally. Most countries in the world require licensing for this antenna to be used with a transmitter. 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 or user agree to defend, indemnify and hold harmless Aareff Systems Limited, its 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.
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