MICROWAVE LINK EVOLUTIONMay 1, 2015Alan Nichols, RF Engineer

Converting Microwave to HD• Four Microwave Dish locations, The Studio and three

towers. Two towers are on Slide and one tower is on Mc Cleland Peak.

Alan Nichols RF Design 2012

From SD Analog to HD Digital ASI & I/P• The three CBS Affiliate ENG vans transmit HD H.264 QPSK to the SLIDE

Mountain receive site, the Studio receive site and the Mc Clellan Peak receive site. Each of the ENG van radios have been changed to NewStream MRC digital radios and the encoder is the Microwave Video Systems HD that accepts the HD/SDI signal and converts it to ASI to enter the NewStream radio.

• Mc Clellan Peak and Slide ENG receive the 2 GH radios TX from the ENG Vans with an MRC 4100 receiver that outputs ASI to the MVS Mux.

• At the CBS Affiliate Studio the G-Line analog radios output ASI to the MVS Decoder that will output HD/SDI to the Video Frame Synchronizer and Embedded Audio to Analog Audio converter to restore the transport stream audio to Analog Stereo to enter the Wheatstone Production Audio console. Lip Sync adjustment is made with the audio delay adjustment and used by the CBS Affiliate studio for live HD News Production.

• The way I accomplished the conversion of the Analog radios to Digital was by using the ASI input on the ENG van radios and using the G-Line base band input for ASI from a MUX. Adding a MUX to the G-Line radios permitted two HD signals from two HD Encoders to enter the MUX and be decoded at the receive site with HD IRD’s for the Live ENG Vans and the HD Tahoe Camera on Slide mountain.

I/P Bullets for control of the receive sites• I used a Spread Spectrum Bullet radio to pass I/P from

the Studio to each ENG mountain site to create the full duplex I/P link. The I/P Bullet also controls the Tahoe Camera and Lamar pan & tilt. The bandwidth of the Bullet is 10 base T.

• I reversed the old Mc Clellan Peak STL link and used the two 7 GHz radios to make this a digital HD link to return ENG to the studio after submitting a 601 Application to the FCC for channel change and TX-RX swap.

• We would like to increase the STL link bandwidth and have full duplex to permit live transfers and also have full I/P control of the Tower site with I/P security cameras.

Performance of the HD Digital ASI & I/P links

The Nissan Xterra has a Horn antenna and it has the best receive gain of all the ENG vehicles. The Tahoe HD Camera is Multiplexed with the ENG signal on Slide Mountain at 9,750 feet is passed in that ENG Digital I/P link to the Studio in Reno. Control of the Pan & Tilt and the HD camera funtions is with the Duplex I/P Bullet in that link.

Microwave link of the future is ASI & I/P• Telco quality Radios that have:• Flexible Modular Design• Additional Power output (+35 dBm) for 16-64QAM • (+38 dBm) for QPSK Modulation for longer link distances• Redundant Power for DC and AC sites• Internal and External Radio configurations with power

inside the building or an HPS on the Antenna• Remote access over I/P to configure radios• SNMP traps to see alarms• Redundant Radio Design to fail over without loss of data• Duplex I/P and HD Video Channels on the same link

GL Link – What is it used for?• GL Links are designed to transport program material and

data between two sites separated up to 50 miles apart• Typical applications include connecting a broadcast studio

to a remote transmitter site, or bringing the output of an ENG receiver back to the studio

• Designed for continuous 24/7 operation• Building large multiple hop networks that are hundreds of

miles long• Connecting remote areas where there is no fiber• Alternate routes for fiber networks prone to “backhoe

fades”

How are Point to Point Radios Different?• Most equipment that we manufacture is designed for ad

hoc operation over relatively short hops. Propagation characteristics are not known in advance

• Long term reliability of microwave paths is not a big factor in wireless camera or ENG operations. The circuit only has to work for a brief amount of time. Some breakup may be acceptable

• Multipath is common with ad hoc operation. Modulations such as DVB-T work well with multipath, but are not as spectrally efficient as other waveforms

• Wireless camera operation usually involves transporting only a single video stream

How are Point to Point Radios Different?• Point to point radios must provide highly reliable circuits• The gold standard for STL reliability is 99.999%, meaning

< 4 minutes of outage per year. Telecoms use 99.9999%• Point to point radios often transport multiple video

streams. Spectrally efficient modulations such as DVB-S are commonly used

• Engineering studies are done in advance to determine propagation characteristics, taking weather history, path length, antenna gains, etc. into account

• Hot standby systems are used to minimize hardware outages

How are Point to Point Radios Different?

• Point to point radios usually use large, highly directional, high gain antennas, often fed through long waveguide runs

• “Split systems” with a separate base station and Out Door Unit (ODU) are also common

• Where a great deal of traffic needs to go between two points, multiple links may share the same set of antennas

• Duplex operation through the same set of antennas is popular

• The most common frequency bands for point to point links in the US are 6, 7, 13, 18 and 24 GHz operating in 20, 25, or 30 MHz wide channels

Point to Point Link Antennas• Parabolic antennas with diameters 6’ – 10’ are required by the FCC

• Very high gain – An 8’ antenna at 13 GHz has a gain of ~47 dBi

• Extremely narrow beam width, typically < 2°

• Knowing predicted signal level is essential for proper alignment

Path Study and Link Budget• Designing a GL systems starts with a path study

• All parameters affecting link reliability, including the weather are taken into account

• Received signal level is accurately predicted

• Annual minutes of outage are predicted

Univision Sinwest Project• > 500 mile long backbone running along the West Coast

• 19 Nodes and growing• Most traffic is IP• Operational since 2012• GL link is Univision’s radio of choice for all stations

What is a GL Link?

• The RF Central GL link is a highly versatile modular point to point link system that is continuously evolving.

• Each year, new modules are added to the system, providing new capabilities and preventing obsolescence.

• GL supports both ASI and IP transmission using any Part 74 or Part 101 point to point microwave band.

• It is most commonly used by broadcasters to connect studio and transmitter sites, but there are a variety of other applications as well

GL Link - Highlights• Designed from the ground up for

broadcast• Future proof design supports both

ASI and IP transport• Redundant power supplies for high

reliability• Modular design meets any point to

point link need• Split or all indoor systems• Supports up to 4 ASI streams• Built-in encoders available• Quick repair and diagnosis by

exchanging modules

The Most Versatile Point to Point Link

System Ever

GL Link

GL Link - Highlights

• Extensive logging and analysis tools allows for easy fault location in large networks

• NTP Time synchronization of mainframes unifies logging

• Full SNMP management

• Duplex in a single mainframe

• Three transmitter power options

• Built-in encoders and decoders are available

The Most Versatile Point to Point Link

System Ever

GL Link

GL Link Architecture

GL Link – A modular system to meet every need

GL Series Radios – Indoor Systems Verses Outdoor System

Indoor Systems (IDU)

• All active parts are in the mainframe• Easier to service• Link budget must support

waveguide loss and remain reliable• Many radios can be diplexed on one

antenna• Use MFR/2B mainframe

Outdoor System (ODU)

• All non-RF components are in the mainframe

• RF components are located at the antenna eliminating waveguide loss and expense

• Does not support complex systems on one antenna

• Mandatory at frequencies > 13 GHz• Use MFR/2A

GL Series Radios – Indoor Systems Verses Outdoor System

Indoor Systems (IDU) Outdoor System (ODU)

In all candor, the outdoor system also has a mainframe that looks exactly like the one above. I just couldn’t think of a way to show that in an attractive looking slide

7 GHz Duplex Indoor System

Duplex 12 GHz ODU System

MFR/2 Functions• Power distribution to all modules• System management and configuration• Configuration storage• Front panel user interface• System logging and alarms• Supports six modules in slots 0-5• All slots are electrically equivalent with one exception• Modules cannot be damaged by plugging them into the

wrong slot• Modules are not hot swappable

The MST Software Suite• A complete set of tools for GL Link configuration,

monitoring and logging. It is not a fancy web browser• Specialized SNMP manager for configuration and

monitoring• Software update tool• Log viewing tool• Bit rate calculator• ASI routing configuration tool• Telnet Client• Connects to mainframe via Ethernet• Provides graphic representation of the network

MST Alarm Viewer Tool

MST – Bitrate Calculator• The MST bitrate calculator simplifies choosing the correct constellation and symbol rate

MFR/2 Mainframe

Supports Redundant Supplies & Frame I/O

Front Panel Display & Keyboard – Linux CPU

MFR/2 Functions

MFR/2A – Internal IF wiring for use with outdoor units

MFR/2B – Internal IF wiring for use with indoor configurations

70 MHz IF Routing makes the difference!

MFR/2 MST GUI

Meet the Modules – Standard Power Supplies• Supplies power to run entire frame• PWS/13 85-264 VAC• PWS/11 85-264 VAC &18 - 36Vdc• PWS/12 85-264 VAC & 36 - 72Vdc• Except for the input voltages all

supplies are functionally the same• All supplies feature automatic line

voltage switching

Meet the Modules – New Redundant Power Supplies• First shipments were in 2013• Due to conflicts with older

hardware, we did not adopt until late 2014

• One supply comfortably runs entire mainframe

• PWS/A 85-264 VAC • PWS/D 18 – 75 VDC • Requires use of PSI/1 Interface

module• All supplies feature automatic line

voltage switching• Hot Swappable• Mix and Match AC & DC Supplies

Meet the Modules -- DCM/x Down Converter• Converts received signal down to from carrier frequency to 70 MHz • Linear Internal RX down converter• Dual conversion design eliminates image problems• Available in microwave bands from 1.9 GHz to 14.5 GHz• SMA RF input & BNC IF output• Green status light illuminates when unit is operational with no alarms

Meet the Modules -- DCM/x Down Converter

Meet the Modules – UCM/x Up Converters

• Converts signal from 70 MHz to carrier frequency• Dual conversion design eliminates images • Typical power output +24 dBm @ 16-64 QAM• Sufficient power output for many link applications• Bands available from 1.9 GHz to 14.5 GHz• SMA RF out & monitor port (-30dBm) simplifies testing• BNC IF input available

Meet the Modules – UCM/x Up Converters

Meet the Modules – AMP/x Standard Power Amplifier Module

• Amplifies output of up converter from milliwatts to watts• Available in all bands from 2 -13 GHz• ~ +31.5 dBm power output with QPSK modulation• Slightly lower power output 10 GHz and above• - 30 dB SMA monitor port simplifies testing

Meet the Modules – AMP/x Standard Power Amplifier Module

Meet the Modules – The UNM/3 Duplex Modem• Modulates/demodulates ASI to/from

70 MHz• The heart of the system• Fully duplex• Symmetric and asymmetric data

rates• Transports two ASI streams and a

single Ethernet stream• Transparent MUX with 8 virtual

channels• Replaces the UNM/2 single ASI

modem with no Ethernet• Uses a variant of DVB-S modulation

and DVB-T• Constellations from QPSK to 256

QAM

Meet the Modules -- UNM/3 Control Panel

Meet the Modules – UNM/3 Graphic Interface

Meet the Modules – AMH/x High Power Amplifier Module• Available in Part 74 and Part 101 6 GHz bands only• ~ +38 dBm power output with QPSK modulation• ~ +35 dBm power output with 16-64 QAM modulation• Requires the full output of the power supply• Must be the only module in the mainframe• SMA monitor port simplifies testing

Meet the Modules – AMH/x High Power Amplifier Module

Meet the Modules – SFP/4 The Swiss Army Machete of ASI Boards• 4-Way transparent ASI multiplexer• 4-Way transparent ASI demultiplexer• Hitless ASI switch• SMPTE-310 to ASI converter• Does all of the above simultaneously, as well as providing

other functionality too esoteric to mention• Uses ASI SFP’s for I/O

Meet the Modules – SFP/4 The Swiss Army Machete of ASI Boards

Meet the Modules – SFP/4 The Swiss Army Machete of ASI Boards

Meet the Modules – MPA/4 & DMA/4 Transparent Mux• MPA/4 multiplexes up to four ASI Streams into a single stream• DMA/4 demultiplexes the single steam back into four streams• Completely transparent – No PID remapping needed

Meet the Modules – MPA/4

Meet the Modules – DMA/4

Meet the Modules – CDP/2 ODU Interface Card• Powers and controls one transmitter and one receiver head through a length

of LMR400-75 75 Ohm Cable.• Supports full duplex operation• Requires MFR/2A mainframe, not the MFR/2B• Provides power, telemetry and IF signal to ODU• Short circuit to head will not damage module

Meet the Modules – CDP/2 ODU Interface Card

Meet the Modules – Honorable Mentions• ASW/6 Hitless switch for up to six ASI inputs• SWO/5, SWO/6 RF switches for hot standby systems• SFN/1 Single frequency network adapter• TAD/1 T1/E1 adapter card• ENS/1, ENS/2, CDC/1, CDC/2 SD encoder/decoder cards• DCD/1, DCD/2, DCD/3 SD decoder cards• ENR/1, ENR/2 HD encoder/decoder cards• DCA/1, DCA/2 HD Decoder cards• There are even more cards and applications, but you

probably heard enough already!

How does one antenna feed several radios?• By properly using channel

filters and circulators, a single antenna may be shared among multiple radios

• Channel filters pass signals within their passband and reflect out of band energy back towards the source

• Circulators are three port devices that allow energy flow in a single direction. Often, one of the ports connects to a terminating load

• Each radio requires its own circulators and filter

BNTA-1 Branching Tray• The number of frequencies and configurations makes each branching network a custom assembly

BEXT/x Branching Network for ODU’s

• The BEXT/x external diplexer for ODU system provides duplex operation with one antenna

We’re not done!!!• GL links continue to evolve• New modules were introduced at NAB 2015 that

combined up converter, down converter and amplifier into one module

• IP only version in development• Many accessories and applications were not shown here• Portable configurations are available using most of the

gear shown here• Over the past five years millions of dollars worth of GL

equipment was deployed to RF Central customers• Now we are done. Thank you for listening!