

The Aareff 'Cycloid' True Circular Polarization FM Antenna is engineered for professional broadcasters who need exceptional signal performance, especially in challenging geographic areas like The United States, Mexico's mountainous and hilly regions
• This unique square-shaped 'cycloid' antenna delivers true circular polarization—a crucial feature that allows your FM signal to penetrate better through valleys and over rugged terrain, ensuring maximum coverage where standard signals fail.
• Built to handle immense power, it is available in 800W (N type) or 3kW (DIN-716) configurations and constructed from durable Aluminum or Stainless Steel. This high-power capability and robust construction establish its professional broadcast authority.
• Superior Signal Penetration: True circular polarization ensures your signal reaches listeners in mountainous, remote, and urban canyon areas of Mexico and similar geographies.
Experience true circular polarization and immense power handling with the Aareff 'Cycloid' antenna. Designed for professional FM broadcasting, this high-performance, omni-directional antenna offers superior signal quality and coverage.The square-shaped Aareff 'Cycloid' True Circular Polarization FM Antenna is engineered to provide maximum performance and durability for any modern FM broadcasting setup.
The antenna is Wideband Tunable From 87 to 108 MHz. Full wideband frequency tuning is easy using a tuning bar with two distinct positions: one for 87 to 98 MHz and the other for 98 to 108 MHz.
• The tuning bar selects the bottom or top half of the 87 to 108 MHz band.
• Vertical tubes are then adjusted in length to reach the exact frequency.
• A VSWR of less than 1.3 can be expected at the chosen frequency.
The Aareff 'Cycloid' True Circular Polarization FM Antenna system is engineered to provide maximum performance and durability for any modern professional FM broadcasting setup. It offers superior signal quality and omni-directional coverage while delivering exceptional value on the market.
• Polarization and Power: The unique square-shaped 'cycloid' design achieves true circular polarization and is built to handle immense power. It is available in 800W (N type) or 3kW (DIN-716) configurations and constructed from robust Aluminum or Stainless Steel. This makes it arguably the best value and most robust circular antenna available.
• Vertical tubes are then adjusted in length to reach the exact frequency.
• Wideband Tuning: The antenna is fully wideband tunable from 87 to 108 MHz. Full wideband frequency tuning is made easy using a tuning bar with two positions: one for 87 to 98 MHz and the other for 98 to 108 MHz. The vertical tubes are then adjusted in length to arrive at the exact frequency, with an expected VSWR of less than 1.3.
• High Gain Stacking (ERP): For broadcasters seeking maximum power and coverage, increasing the Effective Radiated Power (ERP) is highly encouraged through stacking this antenna. Stacking 2, 4 and 8 Way Circular Antennasis standard practice, which can be accomplished using traditional splitters or by driving each antenna from separate amplifiers up to 3kW each. For example, stacking eight of these antennas, each driven by a 3kW amplifier, achieves a powerful radiated circular polarized signal of 150kW EIRP or 90kW ERP, representing the maximum practical size for FM broadcasts.
We understand that time is money. This antenna features an easy assembling design, making it suitable even for novices to install quickly and correctly. Its omni-directional pattern guarantees even signal distribution in a 360-degree radius.
Capable of handling a massive 3kW (3000 Watt) power load, this antenna ensures your signal is broadcast far and wide with exceptional clarity. The unique cycloid design guarantees true circular polarization, which is crucial for minimizing signal fades (multipath distortion) in urban and rugged terrain, providing a more stable and higher-quality listening experience for your audience.
| Gain (Isotropic) | -0.8dB dBi |
| Frequency Range | 87 - 109 MHz |
| Bandwidth | +/-2.5 MHz 1.5 VSWR |
| Construction | Aluminum and Teflon |
| RF Connectors | N type / DIN 7-16 |
| Impedance | 50 ohm unbalanced |
| Polarization | Circular |
| Maximum RF Power | 0.8kW / 3kW |
| Weight of Antenna | 2.3Kg / 3.9kg |
| Wind Speed Handling | 90 MPH |
Incorrect antenna can cause RF burns and levels of RF exposure above the recommended limits for personnelUnder NO CIRCUMSTANCES should the antenna be mounted and used at ground level or within a few meters of personnel.
A tuned antenna with the 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 PL259 (UHF) or N type, depending which is fitted to the FM transmitter.
Ensure that all antenna connections are sound, this is important as poor connections and soldered joints can cause RF burns to personnel, severe noise to the transmission and excessive RF bandwidth. Do NOT connect the antenna to the transmitter yet.
Ideally the antenna for this transmitter 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 3000 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.
| Qty | Antenna Parts |
| 1 | A. Cycloid (square) main dipole with RF connector and Teflon support |
| 2 | B. Vertical radiator with: ◼ 1 x M6 x 50mm screw ◼ 1 x M6 washer ◼ 1 x M6 spring washer ◼ 1 x 25mm diameter tube ◼ 1 x 19mm diameter tube ◼ 1 x 25mm hose clamp |
| 1 | C. Joining clamps with: ◼ 4 x M6 x 50mm screw ◼ 8 x M6 washers ◼ 4 x M6 spring washers ◼ 4 x M6 nuts |
| 1 | D. Boom extension |
| 1 | E. Tuning arm / gamma match bars with: ◼ 2 x M4 screw (7-16) / 1 x M4 Allen head screw (N-Type) ◼ 4 x M4 washers (7-16) / 2 x M4 washers (N-Type) ◼ 2 x M4 Spring ◼ 2 x M4 nut (7-16) / 1 x M4 nut (N-Type) ◼ 2 x M6 x 50mm screws ◼ 4 x M6 washers ◼ 2 x M6 spring washers ◼ 2 x M6 nuts ◼ 1 x 10mm aluminum sleeve |
| Qty | Antenna Parts |
| 1 | F. Mast fixing clamps with: ◼ 2 x U-bolts ◼ 4 x M8 washers ◼ 4 x M8 spring washers ◼ 4 x M8 nuts ◼ 4 x M6 x 50mm screws ◼ 8 x M6 washers ◼ 4 x M6 spring washers ◼ 4 x M6 nuts |
◼ PVC or better Self Amalgamating Tape
◼ Metric Tape Measure
◼ 7mm, 10mm, 13mm Spanner
◼ Phillips screwdriver for M4 screw for 7-16 model
◼ Allen key 3mm for N-Type model
Assemble the four cycloid dipoles exactly as shown in the image. Make sure the spring washer and plain washer are used together, next to one and other, and tightened, this will prevent the screws working loose in the wind.
For best performance, all the pieces marked with '1' should go with each other, then '2', '3' and '4'. This is the way and order they were tested at our factory.
| MHz | Tuning Arm (E) | L cm |
|---|---|---|
| 88 | LO | 44 |
| 93 | LO | 39 |
| 98 | LO | 34 |
| 98 | HI | 33 |
| 103 | HI | 29 |
| 108 | HI | 25 |
Select from the table the frequency that is the nearest match to your frequency and the position of the Tuning Arm (E) and the length L cm.
Using M6 x 40mm Screws, two plain washers, a spring washer and a nut tighten the Tuning Arm (E) into the LO or Hi position. Loosen the hose clamps on both Vertical Radiators (B) and adjust the length of both as shown in the image to L cm, then re-tighten the hose clamps so the tubes cannot move.
Following is a list of precautions to follow when installing the antenna if placement of antenna and cables is anywhere near power lines.
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 |
| 13 | ![]() |
||
| 26 | ![]() |
![]() |
|
| 39 | ![]() |
||
| 52 | ![]() |
![]() |
![]() |
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 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)