The contours of the map are for rain-rate (mm/h) exceeded for 0.01% of time. The map is positioned in relation to the UK according to the following co-ordinates:
The map of UK rain rates is constructed from British Atmospheric Data Centre and ITU data. A full explanation is given in (legacy) paper RSSP(05-01)/42, available from Ofcom on request.
UK Microwave Link Planning
Planning of Microwave Links requires understanding of Microwave Propagation. For frequencies above 10GHz, rain fade is significant and needs to be taken into account. Modern Microwave Planning tools can incorporate this data and calculations to achieve Availability Calculations for microwave links deployed in all regions worldwide.
Data is from regulator OFCOM document: “OfW 446: Technical Frequency Assignment Criteria for Fixed Point-to-Point Radio Services with Digital Modulation “
Two dependable and high performance microwave links available from reputable commercial microwave vendors are the CableFree FOR3 & HCR models.
CableFree Licensed Microwave Links offer long distance, high capacity and dedicated bandwidth.
The CableFree range of Microwave links include Full Outdoor (FOR3, Diamond), Full Indoor (LHR), Split Mount (HCR, LCR, MMR) and Broadcast (ASI) links to meet varied customer requirements for metro scale and national scale microwave networks. CableFree Microwave links are are available in licensed bands (4-42GHz) as well as unlicensed 5, 17, 24GHz.
FOR3 Full Outdoor 1024QAM Microwave Link
CableFree High Performance Licensed Microwave Radios offer up to 440 Mbps and 880 Mbps Full Duplex payload (1.6Gbps aggregate capacity) and higher up to 3Gbps or more, with a software-selectable mix of SDH, PDH and IP/Ethernet traffic in 4-42GHz licensed frequency bands. Using suitable antennas and sites, ultra-long-distance links exceeding 100km can be achieved.
Introducing CableFree FOR3:
CableFree FOR3 is a Full Outdoor Microwave Link, comprising a fully outdoor radio unit, and just an indoor POE (power over ethernet) injector.
Introducing CableFree HCR:
HCR is a Split-Mount microwave, comprising an Indoor Unit (IDU) and Outdoor Unit (ODU).
Operators often choose Full Outdoor Radios for short links in cities, where rooftop space is limited and costs need to be reduced. Split Mount Radios are used for long-haul links where Space Diversity (SD), XPIC and other techniques are often required
For Further Information
For further information on Microwave Technology and the range of CableFree wireless networking products please Contact Us
Long distance Microwave Links often use Space Diversity to ensure reliable communications between the two end points.
In certain geographic locations, such as over water and in deserts, multipath propagation poses an impediment to long-haul radio performance in the form of intolerable link outages. To compensate, a protection scheme must be applied. Space Diversity is one such widely implemented protection scheme that improves the performance of long-distance microwave radio links.
Microwave links below and above 10GHz
At link frequencies above 10 GHz, the path length of the link is limited by fading due to the occurrence of precipitation, while at link frequencies below 10 GHz rain attenuation has a limited effect on the path length. For this reason, frequencies below 10 GHz are best suited for long-haul communication networks. However, even in these preferred long-haul frequencies, path length and link availability can be limited by another phenomenon—fading caused by multipath propagation.
The probability of fading due to multipath propagation is dependent upon geographic factors such as the locale, the terrain over which the radio waves propagate and the path inclination (angle). The path length itself also has an effect since the likelihood of multipath propagation increases as the path length increases. In general, multipath propagation is more likely to occur in tropical areas, desert areas and in links over large bodies of water
Multipath Propagation
Multipath propagation occurs as a result of one or more waves that are sent out from the transmitting antenna being reflected or deflected back onto a path that leads to the receiving antenna. The reflected/deflected wave is received in addition to the direct path wave.
Why use Multiple Antennas?
Spatial diversity employs multiple antennas, usually with the same characteristics, that are physically separated from one another. Depending upon the expected incidence of the incoming signal, sometimes a space on the order of a wavelength is sufficient. Other times much larger distances are needed.
As the multipath transmission is typically caused by fluctual layers in the atmosphere or at ground level, the delay difference between the direct path and the reflected/deflected paths vary over time. Also, the reflection coefficient (strength of the reflection/deflection) varies over time resulting in erratic fading behavior. By putting a second receive antenna on the tower, with a vertical separation from the first antenna, we create a second set of delay combinations. This technique is called Space Diversity. As described below, selective fading will occur at different frequency notches in the two received signals (one at each antenna) due to different delays, resulting in a significantly higher probability of receiving an undistorted signal.
How to achieve Space Diversity
Space Diversity is usually achieved using two vertically spaced antennas (space diversity), multiple transmitter frequencies (frequency diversity), both space and frequency diversity (quad diversity), or reception using two different antenna patterns (angle diversity). Frequency diversity was the first diversity used by fixed point to point microwave systems. Combining dual‐channel space and frequency diversity produces a powerful diversity improvement receiver configuration. The chapter illustrates the receive signal levels for a quad‐diversity path. The purpose of angle diversity antennas is to mitigate the destructive effects of multipath propagation without using a vertically spaced diversity antenna on the microwave tower.
For Further Information
For further information on Microwave Technology and the range of CableFree wireless networking products please Contact Us
For Microwave Links, the maximum transmission rate in a given bandwidth depends on system spectral efficiency, different equipment classes are here defined. They are based on typical modulation formats and limited by a “minimum Radio Interface Capacity density” (Mbit/s/MHz) shown in table 0. Radio Interface Capacity (RIC) is defined in EN 302 217-1
Radio Interface Capacity (RIC)
The minimum RIC density figures in table 0 are valid only for systems operating on the most common channel separation (CS) equal or higher than 1,75 MHz and taking into account that for channel separations “about” 14 MHz (i.e. from 13,75 MHz to 15,0 MHz), “about” 28 MHz (i.e. from 27,5 MHz to 30 MHz), “about” 56 MHz (i.e. from 55 MHz to 60 MHz) and “about” 112 MHz (i.e. 110 MHz or 112 MHz) the RIC density of actual systems is evaluated only over the “nominal” 14 MHz, 28 MHz, 56 MHz and 112 MHz channel width. Minimum RIC figures for some systems operating on 40 MHz channel separation, with RIC density lower than the minimum requirement in table 0, are defined only in annexes C and Ea. For the special cases of sub-STM-0 capacities (defined in ITU-T Recommendation G.708 [i.63] in annex D, alternative minimum RIC figures are not defined
Many users consider upgrading existing Wireless Links such as Trango to add greater capacity, or network coverage. When considering a wireless vendor, factors generally include:
Vendor Track Record
Vendor Corporate Stability
Product Performance & Reliability
Product Support and Service
Manufacturing Leadtimes
Attractive Vendor Roadmap
Product Pricing including all required options
Generally, Microwave links are required to operate unattended for many years in challenging outdoor environments, and therefore reliable and stable products and vendors are paramount in the selection process.
Turbulence in Wireless Vendor Market Space
Amongst many ongoing changes in the market for Microwave Backhaul and Microwave Transmission vendors, there is ongoing consolidation, M&A, and other activities. Recently, Microwave Vendor Trango Networks ceased trading and customers have reported that there is no longer supply of product, spares or support.
According to some former Trango customers in February 2019,
“Trango Systems has ceased trading trading and no longer or supporting existing installed links. We are therefore forced to find alternative suppliers”
Therefore many former Trango customers are looking for dependable alternative suppliers for Microwave and Radio links
Full Outdoor 1024QAM Microwave Link from CableFree
Upgrade to Latest Microwave Technology for Higher Capacities
Some vendors are fully shipping products today with 1024QAM, XPIC, and upgrades to 2048QAM, XPIC, 10Gbps MMW (Millimeter Wave), which are features above and beyond those achieved by many in the market today. Customers can upgrade today and achieve higher capacity, longer range, reach and availability, at low Total Cost of Ownership compared to competing options.
Future Roadmap for Microwave Upgrades
In addition to today’s products, an impressive roadmap ensures access to higher speed links and features in future products also. Consideration is worthwhile into:
Vendor roadmaps to higher capacity links with microwave up to 4Gbps or more per link existing today.
Upgrading to E-Band MMW for shorter links especially in congested city environments
Using E-band Millimeter Wave for short links to free-up existing microwave spectrum, relief of spectral congestion and re-using valuable microwave spectrum for longer links where required
For More Information on Microwave Upgrades:
For more information on upgrading your Microwave Radio Network, Please Contact Us
A Split Mount Microwave Radio consisted of Indoor plus Outdoor components – specifically Indoor Unit (IDU) and Outdoor Unit (ODU)
Split Mount Microwave Radios offer up to 500 Mbps and 1Gbps Full Duplex payload and higher up to 6Gbps or more, in 4-42GHz licensed frequency bands.
Indoor Unit (IDU)
CableFree HCR Indoor Unit (IDU)
A Typical Split Mount Radio consists of a 19″ Rack Mount Indoor Unit which is mounted in a rack, cabinet, comms room, or even roof-mount shelter as possible locations.
Outdoor Unit (ODU)
CableFree Microwave Link Outdoor Unit (ODU) with using 30cm antenna mounted on a pole
The Outdoor Unit (ODU) is typically mounted directly to the Microwave Antenna on a rooftop or tower location, which enables clear Line of Sight (LOS) between both ends of the Microwave link.
For most bands above 6GHz the ODU has a waveguide interface which enables efficient, low-loss connection directly to the antenna. For lower bands below 6GHz, commonly a coaxial cable is used between the ODU and the antenna.
In certain cases, the ODU can be remote mounted from the antenna, and a waveguide used to connect between them
Comparison with Full Outdoor Radios
A split mount radio is considered a “traditional” design and older radios always feature this. The Indoor Unit has all the network interfaces and processing in the easy-access indoor location at the foot the tower or building. Full Outdoor Radios by contrast have all the active items including the modem and user network interfaces inside the rooftop radio element. This saves on space, materials, installation time and cost. A downside is that in the event of any failure, a tower climb is almost always needed to rectify any fault, which may be impossible in rough weather, or require permits or have access limitations to reach
Distances and Range Capability of Split Mount Radios
Using suitable antennas and sites, ultra-long-distance links exceeding 100km can be achieved. Distances depend on:
Frequency band
Regional Rainfall
Required throughput (Mbps)
Desired Availability (%)
Antenna size (gain)
For Further Information
For more information on Full Outdoor Radios and Microwave Networks please Contact Us
Due to high frequencies used, Waveguides rather than RF coaxial cables are used to connect Microwave Radios, Antennas and Couplers. Matched and correct size and dimension of Waveguide is essential for all items in the Microwave link.
What is a Waveguide?
A waveguide is an electromagnetic feed line that is used for high frequency signals. Waveguides conduct microwave energy at lower loss than coaxial cables and are used in microwave communications, radars and other high frequency applications.
The waveguide must have a certain minimum cross section, relative to the wavelength of the signal to function properly. If wavelength of the signal is too long (Frequency is too low) when compared to the cross section of the waveguide, the electromagnetic fields cannot propagate. The lowest frequency range at which a waveguide will operate is where the cross section is large enough to fit one complete wavelength of the signal.
Rectangular, Circular and Double Rigid
Geometrically speaking there are three types of waveguides – Rectangular Waveguides, Double Rigid Waveguides and Circular Waveguides. The tables below will give you details on the various waveguide sizes and their properties.
The “WR” designation stands for Rectangular Waveguides
The Number that follows “WR” is the width of the waveguide opening in mils, divided by 10. For Example WR-650 means a waveguide whose cross section width is 6500 mils.
The waveguide width determines the lower cutoff frequency and is equal (ideally) to ½ wavelength of the lower cutoff frequency.
Double-ridge waveguides are rectangular wagevuides with two ridges protruding parallel to the short wall. This increases the E-Field in the waveguide improving performance.
Dimension:3.4 Inches [86.36 mm] x 1.7 Inches [43.18 mm]
Microwave Waveguide
What is a Waveguide?
A waveguide is an electromagnetic feed line that is used for high frequency signals. Waveguides conduct microwave energy at lower loss than coaxial cables and are used in microwave communications, radars and other high frequency applications.
The waveguide must have a certain minimum cross section, relative to the wavelength of the signal to function properly. If wavelength of the signal is too long (Frequency is too low) when compared to the cross section of the waveguide, the electromagnetic fields cannot propagate. The lowest frequency range at which a waveguide will operate is where the cross section is large enough to fit one complete wavelength of the signal.
For Further Information
For More Information on Microwave Planning, Please Contact Us
Dimension:9.75 Inches [247.65 mm] x 4.875 Inches [123.825 mm]
Microwave Waveguide
What is a Waveguide?
A waveguide is an electromagnetic feed line that is used for high frequency signals. Waveguides conduct microwave energy at lower loss than coaxial cables and are used in microwave communications, radars and other high frequency applications.
The waveguide must have a certain minimum cross section, relative to the wavelength of the signal to function properly. If wavelength of the signal is too long (Frequency is too low) when compared to the cross section of the waveguide, the electromagnetic fields cannot propagate. The lowest frequency range at which a waveguide will operate is where the cross section is large enough to fit one complete wavelength of the signal.
For Further Information
For More Information on Microwave Planning, Please Contact Us
Dimension:11.5 Inches [292.1 mm] x 5.75 Inches [146.05 mm]
Microwave Waveguide
What is a Waveguide?
A waveguide is an electromagnetic feed line that is used for high frequency signals. Waveguides conduct microwave energy at lower loss than coaxial cables and are used in microwave communications, radars and other high frequency applications.
The waveguide must have a certain minimum cross section, relative to the wavelength of the signal to function properly. If wavelength of the signal is too long (Frequency is too low) when compared to the cross section of the waveguide, the electromagnetic fields cannot propagate. The lowest frequency range at which a waveguide will operate is where the cross section is large enough to fit one complete wavelength of the signal.
For Further Information
For More Information on Microwave Planning, Please Contact Us
You must be logged in to post a comment.