Antenna is the Key to Transmitting Range and Quality
The transmission range of a wireless system is determined by the transmitter's output power and the receiver's sensitivity. Ideally, if a user can increase the output power of the transmitter, they should be able to increase their system's range. However, this is usually not possible since the transmitter's output power is already preset during production. In addition, an increase in transmitting power is hindered by wireless regulations, interference between multiple systems and a shortage of transmitter operating hours due to higher battery voltage consumption. The alternative is to increase the sensitivity level of the receiver. Theoretically speaking, the transmitting range doubles with an increase of 6dB in sensitivity. In real life, however, the user cannot easily adjust the sensitivity level since it is integrated with the antenna. In application, since the signal is received via the receiver's antenna, the proper selection of an antenna is vital to the system's overall range and performance.
MIPRO Antenna Types and Characteristics
A mountable antenna is carefully designed and selected to match the input impedance of the receiver while still offering the user a degree of flexibility. MIPRO's receiver antennas have several designs:
Whip Antenna:
1/4-wave, single rod antenna. It is omni-directional and rated at 50ohms. It is a metallic dipole antenna designed to mount directly on the receiver antenna connectors and provides adequate operating range and sensitivity level in most (many?) applications.
Coaxial Antenna:
1/2-wave antenna. It functions like a dipole antenna, having standard 2.4dBi, 50ohm and omni-directional characteristics. It is mounted directly on the receiver antenna connectors and provides good operating range and a higher sensitivity level.
AT-70 Ground Plane Antenna:
It provides a significant gain over the 1/4-wave monopole. The best impedance match is provided when the radials are angled downward from the vertical at a 45-degree angle, causing a 1/2-wave dipole antenna effect. A ground plane antenna exhibits a circular coverage pattern, perpendicular to the vertical element. The antenna should be positioned so that the radials are closest to the nearest boundary such as a central location on the floor, wall or ceiling and functions best when inverted.
AT-70W Wideband Transmitting & Receiving Omni-directional Antenna:
AT-70W is a bi-functional omni-directional antenna for professional receiving and transmitting applications. Optimized for 470~1000 MHz, which is fully compatible with US and EU new telecom regulations. It has a 2~4 dBi gain which is ideal for any specific installation required with full directions. It can be easily distinguished by its new “W-Shape” appearance.
AT-70W has two input connectors, “TX/RX” which can be connected to transmitter or receiver directly. The “RX Only” connector has a built-in 12 dB high gain booster provides increased reception range for ACT receiver.
AT-70W offers users the options of transmitting or receiving based on actual application. Built-in booster power can be provided from a MIPRO AD-707a or ACT Series receivers through the coaxial cables. AT-70W is waterproof and ideal for both indoor and outdoor applications.
AT-90W Wideband Transmitting & Receiving Log Antenna:
AT-90W is a bi-functional log antenna for professional receiving and transmitting applications. Optimized for 470~1000 MHz, which is compatible with US and EU new telecom regulations. It has a 4~6 dBi gain which is ideal for any installation required specific directions. The wideband ACT-90W can be easily distinguished from its predecessor, AT-90, by its new “W-Shaped” design.
AT-90W has two input connectors, “TX/RX” which can be connected to transmitter or receiver directly. The “RX only” connector has a built-in 12 dB high gain booster provides increased reception range for ACT receiver.
AT-90W offers users the options of transmitting or receiving based on actual application. Built-in booster power can be provided from a MIPRO AD-707a or ACT Series receivers through the coaxial cables. AT-90W is waterproof and ideal for both indoor and outdoor applications.
AT-100 Wideband Circularly Polarized Antenna:
AT-100 is an active directional antenna. It is designed for demanding professional stages and will greatly improve signal stability and reduce interferences, signal drop-outs caused by polarization problems.
Front area is the main focus of antenna direction for either vertical or horizontal polarization.
Circularly polarized antenna can effectively reduce the polarization loss of the antenna to improve signals strength. Optimum solution for 470-1,000 MHz bandwidth with 6~8 dBi antenna gain and certified to latest CE/FCC newly telecom regulations.
How to install antenna for best reception
For optimal performance, the selection and placement of the receiver and antenna are most critical. The below applications illustrate the basic principals and suggestions.
Single-channel fixed frequency and multiple single-channel fixed frequencies, indoor or outdoor, short-range applications.
This is the basic installation for home karaoke, small conference or concert venues. Select MIPRO MR-823 receiver(s) and fit each with a pair of whip antennas ~ simply mount them securely on the antenna connectors. Place the antennas vertically, away from metallic objects and noise sources. Note that the receiving efficiency deteriorates if more than three receivers are installed together.
Single, Dual and Quad channels, indoor or outdoor, long-range application
Live stages need professional true diversity receiver models such as the MIPRO ACT-series like ACT-71/72/74 or ACT-717/727/747 receivers. Antenna selection becomes a crucial issue in these applications. A pair of coaxial antennas is provided with all ACT-series receivers ~ simply mount them securely on the antenna connectors.
An AT-70 extension antenna is needed for extended range. Place it as high as possible above the floor, keeping in mind that signal loss occurs if the connecting cable is too long. To compensate for such signal loss, the addition of MPB-20 antenna booster is recommended. A MPB-20 booster can be powered by either the AD-707a wideband antenna divider system or any ACT-series receivers.
It is recommended that an AT-90TW wideband transmitting and receiving directional antenna be used in difficult, multiple-system environments. It has superb receiving and transmitting performance when pointing at specific direction. It is simple to install and gives better results.
If three of more receivers are installed in the same location, adding a AD-707a 4-channel wideband antenna divider system with extension antenna will enhance the receiving range and effect.
Four or more channels, indoor or outdoor, long-range applications
An AD-707a wideband antenna divider system and extension antenna are highly recommended for four or more ACT receivers in the same installation.
To save and maximize rack space, one ACT-74 or ACT-747 professional 4-channel receiver is an ideal choice. It is compact, space-saving and has a built-in antenna divider system, thus there is no need for an external antenna divider system to achieve the same performance.
16 channels, indoor or outdoor, long-range applications
Four receiver systems of ACT-74 or ACT-747, a total of 16 channels, connected to one AD-707a antenna divider system and a pair of AT-90W active directional antenna are recommended. System output gain equals 1.
Antenna Design and Placement Principals of Multiple Systems
Select receivers with a built-in active antenna divider system such as the ACT-74 or ACT-747 to avoid loss of receiving sensitivity.
Add an external ACT-707a antenna divider system when 2 or more ACT series receivers are installed.
Add an external ACT-707a antenna divider system, extension antenna and boosters when 3 or more receivers are installed.
In multiple channel installations with 2 or 4 antenna divider systems, daisy chain one more antenna divider system to them in order to feed the signal to all of them from 1 pair of antennas. The maximum number of MIPRO receivers housed in a single rack space is 4 channels. If more than 64 channels are needed, it is advised to create a new system to optimize the reception quality.
The selection of AT-90W active directional antennas enhances receiving quality, especially in a difficult, RF environment.
How to Design Receiver's Antenna System
First, estimate antenna's transmission distance and frequency of transmitting signals. Then, find a suitable cable specification accordingly to its tolerance.
Classifications of tolerance range on receiver system's signal loss:
A. Wider tolerance on signal loss: <-10dB~-6dB
B. Acceptable tolerance on signal loss: -6dB~-2dB
C. Narrower tolerance on signal loss: <-2dB
Greater cable loss will decrease receiving distance and system stability, booster must be added to offer enough gain to make up the loss. However, booster should not offer excessive gain as it will cause receiver's intermodulation distortion and create unnecessary interference to affect receiving quality.
Following chart tells specification of cable, suitable antenna and booster needed based on transmitting distance and tolerance range of signal loss. |
