ViaLite HRX-Y-HB-2 User manual

Mil-Aero RF over fibre link Handbook
10MHz –6GHz
User Guide
HRX-Y-HB-2
CR5048 21/04/2022
Pulse Power & Measurement Ltd, 65 Shrivenham Hundred Business Park, Watchfield, Swindon, Wiltshire SN68TY, UK
Tel [phone] Email [email protected] Web www.vialite.com

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
2
Instrument Care and Safety Information
Please read the whole of this section before using your ViaLiteHD product. It contains important safety
information and will enable you to get the most from your Fibre Optic link.
Electrical Safety
The ViaLiteHD chassis is a Safety Class 1 product (having metal chassis directly connected
to earth via the power cable).
When operating the equipment note the following precautions:
Hazardous voltages exist within the rack mounted equipment.
There are no user serviceable parts inside; the covers MUST NOT be removed.
There are no user replaceable fuses in the chassis mounted equipment or OEM modules.
The chassis earth stud SHOULD be connected to the safety earth.
When using a 2 pin power supply cable the chassis earth stud MUST be connected to
the safety earth.
The ViaLiteHD Power Supply Modules do not have an isolating switch on the mains
voltage inlet. For this reason, the ViaLiteHD chassis MUST be installed within easy
reach of a clearly labelled dual pole mains isolation switch, which supplies the equipment.
PSU modules are fused on the mains live feed only. A second fuse should be used for
the neutral connection where the polarity of the connectors can be reversed; rating should
match those given in section Error! Reference source not found..
ESD Precautions Precautions for handling electro-static sensitive devices should be observed when handling
all ViaLite modules. Technicians should ensure that they use effective personal grounding
(i.e. ESD wrist strap etc.) when servicing the equipment. Any equipment or tools used
should be grounded to prevent static charge build-up. Good practice should be observed at
all times. For reference see relevant standards.
EN 61340-5-1, “Protection of Electronic Devices from Electrostatic Phenomena – General
Requirements”
Optical Safety The ViaLite RF Transmitter and Transceiver modules contain laser diode sources operating
at nominal wavelengths of 1270nm to 1610nm.
These devices are rated as EN60825-1 CLASS 1 radiation emitting devices. A class 1 laser
is safe under all conditions of normal use.
When operating the equipment note the following precautions:
Never look into the end of an optical fibre directly or by reflection either with the naked
eye or through an optical instrument.
Never leave equipment with radiating bare fibres –always cap the connectors.
Do not remove equipment external covers when operating.
Hot surface The ViaLite systems may have hot surfaces when operating under full load. The hot
surfaces are not accessible when fitted in an approved chassis installation. Hot surfaces
will be appropriately marked
Suitable precaution should be taken when handling this device.
Allow to cool for 10 minutes
Do not touch metallic surfaces or printed circuit board when hot.
When handling, hold front panel and handle only.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
3
TABLE OF CONTENTS
1INTRODUCTION ......................................................................................................................................... 5
1.1 Typical deployment.............................................................................................................................5
1.2 ViaLiteHD compatibility.......................................................................................................................5
1.3 Care of fibre optic connectors.............................................................................................................5
2SETUP AND OPERATION OF THE FIBRE OPTIC LINK........................................................................... 6
2.1 Module Type overview........................................................................................................................6
Rack card .................................................................................................................................6
Blue OEM.................................................................................................................................7
Power supply.............................................................................................................7
Black IP rated OEM..................................................................................................................8
Mounting and sealing................................................................................................8
Power supply.............................................................................................................8
2.2 Fibre optic interface............................................................................................................................9
Connector and cable types.......................................................................................................9
Connecting and disconnecting.................................................................................................9
Cleaning optical connectors, cleaning before every use..........................................................9
Cleaning optical connectors, high levels of contamination ......................................................9
FC/APC Connectors...............................................................................................................10
SC/APC Connectors...............................................................................................................10
Minimum bend radius.............................................................................................................11
2.3 RF Interface......................................................................................................................................11
SMA connections ...................................................................................................................11
2.4 Front panel indicators.......................................................................................................................12
Rack card LEDs......................................................................................................................12
Blue and Black OEM LED......................................................................................................12
2.5 I/O connections and features............................................................................................................13
Analogue monitors .................................................................................................................13
RF Bias-T ...............................................................................................................................13
Active antenna failure detection (AFD) ..................................................................................14
Alarm voltage..........................................................................................................................14
Blue OEM 10 pin user connector ...........................................................................................14
Receiver RLL AGC function...................................................................................................15
2.6 Dual rack card variants.....................................................................................................................15
2.7 USB CLI command and control........................................................................................................15
Connection configuration........................................................................................................16
Command set.........................................................................................................................16
2.8 Rack card web interface via the HRC-3 ...........................................................................................17
3SYSTEM INTEGRATION........................................................................................................................... 18
3.1 Link gain ...........................................................................................................................................18
Transmitter gain......................................................................................................................18
Fibre loss................................................................................................................................18
Receiver gain..........................................................................................................................18
Gain selection for optimum link performance.........................................................................19
3.2 Frequency response.........................................................................................................................20
3.3 VSWR...............................................................................................................................................20
3.4 Noise Figure .....................................................................................................................................20
Noise figure vs link loss..........................................................................................................20
3.5 P1dB Compression...........................................................................................................................21
3.6 IP3 Linearity......................................................................................................................................21
3.7 Spurious Free Dynamic Range (SFDR)...........................................................................................21
SFDR vs link loss ...................................................................................................................21
3.8 Link delay..........................................................................................................................................22
3.9 Deviation from linear phase..............................................................................................................22

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
4
4MECHANICAL DETAILS ........................................................................................................................... 23
4.1 Blue OEM module dimensions .........................................................................................................23
4.2 Blue OEM connector positions .........................................................................................................23
4.3 Black OEM module dimensions........................................................................................................24
4.4 Black OEM connector positions........................................................................................................24
5PART NUMBERING .................................................................................................................................. 25
6TECHNICAL SPECIFICATIONS................................................................................................................ 26
7MAINTENANCE AND FAULT FINDING.................................................................................................... 27
7.1 Green status indication.....................................................................................................................27
7.2 Red status indication ........................................................................................................................27
8PRODUCT WARRANTY............................................................................................................................ 28

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
5
1 Introduction
The ViaLiteHD RF Fibre Optic Links (FOLs) are a family of fibre optically coupled link systems designed for the
transmission of RF analogue signals over long distances for the communications market.
This handbook covers the following ViaLiteHD RF Link part numbers:
Transmitter modules (electrical »optical) with part numbers starting:
oHRT-Y
Receiver modules (optical » electrical) with part numbers starting:
oHRR-Y
Transceiver modules (optical » electrical + electrical »optical) with part numbers starting:
oHRX-Y
Dual Receiver modules (2x optical » electrical) with part numbers starting:
oHRV-Y
Dual Transmitter modules (2x electrical »optical) with part numbers starting:
oHRU-Y
For complete information and product familiarisation, this handbook should be read in conjunction with all other
relevant handbooks for your ViaLiteHD system.
ViaLiteHD is a product brand manufactured by Pulse Power and Measurement Ltd (PPM).
ViaLite Communications is a division of Pulse Power and Measurement Ltd (PPM).
1.1 Typical deployment
The user’s RF electrical signal is input to the transmitter module, which contains RF signal conditioning and
laser control circuitry. The module modulates the intensity of a beam of light with the RF signal.
The light travels through an optical fibre to the receiver module. The distance between transmitter and receiver
can range from 1m to 100km; distance in excess of 100km can be achieved with more complex optical transport
systems, depending on the system specified.
The receiver module converts the modulated light back into an electrical signal, which is available at the output
of the module.
1.2 ViaLiteHD compatibility
The RF and optical interfaces are compatible with all ViaLiteHD Rack cards, ViaLiteHD Blue OEM modules
and ViaLiteHD Black IP rated outdoor modules.
18 Laser wavelength options are available for multiplexed applications using CWDM.
Contact ViaLite Communications or your local ViaLite agent for more details.
1.3 Care of fibre optic connectors
When the fibre optic cables are not connected, it is essential that the cable and equipment connectors are
protected by the dust caps provided with the system. Failure to do so may result in damage to the fibre ends
which are critical to the system performance. Please refer to section 2.1.3.2 for further details.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
6
2 Setup and operation of the fibre optic link
This section describes the setup and operation of the fibre optic link in the various form factors available.
2.1 Module Type overview
Rack card
All ViaLiteHD plug-in modules are hot-swappable, so it is not necessary to
power-down the chassis before inserting a module. All standard optical
connectors are retained by the module, so it will be necessary to either
disconnect any cables or have a sufficiently long service loop when
removing modules.
To install a 5HP standard module and matching interface plate:
The protective covers on the connectors may be left in place.
Push the release button of the module handle down and simultaneously
pull the top of the handle towards you.
Align the module upright and perpendicular to the front face of the chassis
so that the PCB slides into the “crow’s feet” card guides top and bottom.
Gently push the module down its guide, applying pressure via the handle,
you may also apply pressure between just above the LEDs.
As the module is fully mated the top of the handle should snap back and
lock in position.
The pawls of the handle should be fully engaged in the matching slots.
If power is applied to the chassis the module power LED should light as soon as the module is fully inserted.
Remove protective covers on the rear interfaces and connect the cables.
To remove a 5HP Standard module
Disconnect the rear interface cables and fit protective covers.
Push the release button of the module handle down and simultaneously pull the top of the handle forwards.
Apply pressure via the handle and gently withdraw the module from the chassis.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
7
Blue OEM
The Blue link module is fully enclosed and built with connectorised interfaces with electromagnetic shielding.
This allows system integrators and equipment manufacturers an easy route to build RF/optical interfaces into
their own equipment. The small form factor and integrated design should allow the module to be effortlessly
integrated into end user equipment. Ensure all RF and optical ports are terminated to user equipment and
cabling prior to supplying DC power.
Power supply
The Blue OEM is supplied with a 12V power supply for international operation by way of the accompanied
fittings. Replacements can be ordered using ViaLite part number 73502. The power supply has capacity to
power external RF amplifiers by way of the blue module’s internal bias-T.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
8
Black IP rated OEM
The Black link module is an IP55 sealed enclosure suitable for outdoor use. It is ideal for placing close to
antennas that are open to the elements. The high gain transmitter module with its low noise figure can in some
cases be used without the need for an antenna LNA in downlink applications. If an LNA is required, the built-in
Bias-T offers the user a convenient application path.
Mounting and sealing
To ensure the IP rating is met, please make sure the USB port bung is replaced after any configuration or
maintenance work. Furthermore, ensure the RF and optical connections are wrapped in self-amalgamating tape
with the unit mounted vertically such that the cables exit beneath the unit. This will prevent moisture pooling
around the connector fittings by allowing gravity to drain it away.
For optimal performance and product longevity, always mount the module shaded from direct sunlight. Ensure
all RF and optical ports are terminated to user equipment and cabling prior to supplying DC power.
The IP55 rating is only achieved when the USB bung is tightly sealed and when the RF
and Optical ports are wrapped in self-amalgamating tape and vertically mounted with
the cables hanging beneath the module. Installation should be carried out by a suitable
trained technician.
Power supply
The black OEM module is supplied with a power connector and 2m power tails only. Replacements can be
obtained using ViaLite part number 73955. The power connector is a Hirose part HR30-6PA-3S(71).
The Black OEM can be optionally supplied with the outdoor IP rated power supply module 70094. The IP rated
power supply has capacity to power external RF amplifiers by way of the black OEM module’s internal bias-T.
The AC input must be user terminated inside the box with the available site mains and sealed via the cable
gland. The DC side comes pre-fitted with a sealed 2m length of cable and black OEM power connector. For
further details, please consult the handbook supplied with the 70094 PSU.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
9
2.2 Fibre optic interface
Connector and cable types
All ViaLiteHD RF modules use single-mode (9µm/125µm) cable terminated in a range of optical connectors
detailed below. Cross-site fibre optic cables are available from ViaLite Communications as either standard
patch leads or heavy-duty multicore cables.
Warning!
Angle polished (APC) and standard (PC) connectors must not be confused. The two
connector types are not interchangeable and mating one with the other may damage both
the cable and the module connectors.
The specification of optical connector is critical to the performance of the complete fibre
optic link. System performance can only be guaranteed with fibre optic cables and
connectors supplied by ViaLite Communications. When FC/APC connectors are specified
they must be “narrow key width”.
Connecting and disconnecting
Before connecting optical fibres to the module or to each other, ensure that the mating connectors are clean
(see below).
Cleaning optical connectors, cleaning before every use
Optical connectors MUST be cleaned before use, even where they have been protected with dust caps.
A large percentage of performance issues can be attributed to dirty fibres.
For more details please read the cleaning instruction which accompanies the connector cleaning kit.
Cleaning optical connectors, high levels of contamination
If there are performance issues that are not resolved by basic cleaning in section 2.2.3, then the following
procedure should be used. If the level of contamination is high it will be necessary to repeat this procedure.
Cleaning items required
Lint free fibre cleaning tissues and/or cleaning sticks (normal cosmetic tissues produce dust and are not
acceptable).
Reagent grade Isopropyl alcohol (IPA).
Air duster or filtered compressed air line.
Cable Connector Cleaning
Dampen a patch of cleaning tissue with IPA and clean all surfaces of the plug ferrule.
Peel the plastic cover from an unused “N”
cleaning pad.
Hold the connector between your thumb and
forefinger
Clean the connector using firm pressure by
swiping in a pendulum motion through each
segment of the “N” shape, following the
diagram
Do not swipe over the same space twice.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
10
Using a dry cleaning tissue, dry the ferrule and clean the end face.
Using the air duster, blow away any residue from the end of the connector.
Module Female Receptacle Cleaning (only recommended if problems are being experienced)
Either use an optical cleaning stick or twist a cleaning tissue to form a stiff probe, moisten either with IPA.
Gently push the probe into the receptacle and twist around several times to dislodge any dirt.
Repeat the above process with a dry tissue.
Using the air duster, blow away any residue from the receptacle.
Important Notes
IPA is flammable. Follow appropriate precautions / local guidelines when handling and storing.
IPA can be harmful if spilt on skin. Use appropriate protection when handling.
It should only be necessary to clean the female receptacles on the modules if problems are being
experienced.
Never inspect an optical fibre or connector with the naked eye or an instrument unless
you are certain that there is no optical radiation being emitted by the fibre. Remove all
power sources to all modules, and completely disconnect the optical fibres.
FC/APC Connectors
To connect FC/APC optical connectors follow these steps:
Remove the dust caps and align the white ceramic centre ferrule on the cable connector with the mating
receptacle.
There is a key (lug) on the side of the ferrule, which must match the keyway (gap) in the receptacle shroud.
When they are aligned, gently push the plug home.
Finger tighten the knurled collet nut onto the threaded receptacle.
To disconnect follow these steps:
Using fingers fully unscrew the knurled collet nut, gently withdraw the connector.
Replace the dust caps on both the receptacle and the cable plug.
Warning! It is possible to tighten the knurled collet without aligning the lug and gap. This will
result in poor light transmission. Check that the lug and gap are aligned before tightening the
knurled collet
SC/APC Connectors
To connect SC/APC optical connectors follow these steps:

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
11
Remove the plug protective cover.
Align the connector keyway slot in the adaptor to the key of the plug.
Gently push the plug-into the adapter until a click is heard and the connector locks.
To disconnect follow these steps:
Grip the body of the plug and gently pull the plug from the adaptor, replace the protective cover.
Only connect SC/APC cable to SC/APC.
Minimum bend radius
Because optical fibre is made of glass, it is important not to subject it to excessive stress. For this reason, each
type of cable has a minimum bend radius (MBR) specification, beyond which the cable cannot be bent without
permanent damage occurring.
The minimum bend radius (MBR) of fibre optic cable fitted to ViaLite modules is 50mm. MBR specifications for
ViaLite Communications supplied fibre optic cables are given in the ViaLiteHD System Handbook Hxx-HB.
2.3 RF Interface
SMA connections
The high frequency RF converters are fitted with SMA connectors. SMA connectors offer excellent performance
but must be clean, free of dust and contaminants and tightened to the correct torque. Please ensure that an
SMA torque spanner set to 1.0Nm is used to make the connections. An example torque wrench is shown below
(Huber Suhner 74_Z-0-0-21) 1Nm 8mm/.315 inch.
Over tightening an SMA with a standard 8mm spanner will risk twisting of the connection
behind the bulkhead and damage may occur that impacts the performance of the link. Always
use a 1Nm torque wrench.
Connect and tighten RF connectors to present the correct termination impedance before
applying power to the modules.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
12
2.4 Front panel indicators
Rack card LEDs
Plug-in modules have three front panel LEDs for a visual indication of its state. The following table shows the
operation of the front panel LEDs which are dependent on module type.
Colour
Plug-in
Single
Transmitter
Plug-in
Single
Receiver
Plug-in
Transceiver
Plug-in
Dual
Transmitter
Plug-in
Dual
Receiver
LED1
(PWR)
GREEN
Normal
No light
TX PSU fail
RX PSU fail
PSU fail
PSU fail
PSU fail
LED2
(ALA)
GREEN
Normal
RED
TX Alarm
RX Alarm
TX & RX
Alarm
TX1 & TX2
Alarm
RX1 & RX2
Alarm
RED + Pulsing
ORANGE 1 PPS
N/A
N/A
TX Alarm
TX1 Alarm
RX1 Alarm
RED + Pulsing
ORANGE 2 PPS
N/A
N/A
RX Alarm
TX2 Alarm
RX2 Alarm
Flashing
RED/GREEN
Programming –Warning, do not remove power to the unit
LED3
(M&C)
GREEN
I2C enabled
Flashing
GREEN
I2C active
ORANGE
I2C disabled
Blue and Black OEM LED
These modules are fitted with a single status LED for indication of the state of the module. On the blue module
it is placed just below the fibre connector and on the black it is placed above and to the left of the fibre connector
as shown below.
An alarm condition on a transmitter module indicates the inability to reach target laser power.
An alarm condition on a receiver module indicates insufficient or no received light level (RLL)
Colour
Blue
OEM
Black
OEM
LED
GREEN
Normal
RED
Alarm
No Light
No power

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
13
2.5 I/O connections and features
Analogue monitors
Rack cards and blue OEM modules have analogue monitor ports. These can be set via software to reflect either
the RF or optical power level within the module. The range of the output is 0 –2V.
When configured to reflect optical power, 2V
represents maximum rated optical power (typically
3.0mW). The analogue scale follows at -12.2dB per
Volt.
When configured to reflect RF power, 1.5V
represents 10dB above the measurement noise
floor. The RF detector system is for indication only
as the dynamic range is fairly limited. The example
given here is for a standard gain transmittermodule.
RF Bias-T
The Blue, Black and rack modules all have an integrated Bias-T for powering external amplifiers or other in-line
RF devices. The Rack and Blue modules have an option to pass in a separate user voltage for this purpose if
the standard built-in options aren’t suitable.
The bias-T circuit is over-current protected and is capable of supplying up to 250mA. The bias-T voltage and
current drawn by the external device can be monitored from the USB and SNMP interfaces.
The user configurable options for the Bias-T function are as follows:
Disabled.
No voltage is present on the RF port.
Power supply pass-through.
The main module power supply voltage is passed on to the Bias-T.
Internally generated 5V.
Customer supplied independent voltage (Rack and Blue OEM only).
0.00
0.50
1.00
1.50
2.00
2.50
-25 -20 -15 -10 -5 0 5 10
Analogue monitor (Volts)
Optical Power (dBm)
Analogue monitor -Optical mode
0.00
0.50
1.00
1.50
2.00
2.50
-50 -40 -30 -20 -10 0
Analogue monitor (Volts)
RF Power (dBm)
Analogue monitor -RF mode

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
14
Active antenna failure detection (AFD)
The Blue, Black and rack transmitter modules all have an optional AFD feature. This feature is used in
conjunction with the bias-T to monitor and remotely report the failure of an active antenna. When enabled, this
feature will check that the bias-T is supplying the correct current to an active antenna LNA. If the current falls
below a user configurable threshold, the laser is disabled which causes the receive end of the link to alarm due
to the lack of light. This feature is useful to quickly alert the user of a remote LNA failure which could be 10s of
km away with no networked monitoring. A failed LNA could go undetected for some time depending on the
nature of the received signal as the link would otherwise still function with the de-sensitised antenna.
The AFD current threshold can be user configured from between 2mA and 200mA.
Alarm voltage
The blue and rack modules have a pin on the I/O for external alarm monitoring. This can be used for fast
hardware switching of redundant links for example. The interface is open-drain and will float in the event of an
alarm to enable pull up to the user side voltage.
Blue OEM 10 pin user connector
The blue OEM module is equipped with a 10-pin user accessible port for further integration capability. The pin
identification and function is shown below.
Pin Number
Name
Function
1
GND
Ground connection
2
Vin
12V Power in (9-18V) (Alternative to 2.1mm Jack)
3
N/C
UNUSED
4
Ext_Bias
User supplied RF port Bias-T voltage (SW enabled)
5
N/C
UNUSED
6
LEV_MON1
Analogue level monitor (RF or optical power)
7
GND
Ground connection
8
N/C
UNUSED
9
SCL
I2C control clock
10
SDA
I2C control data
The OEM module is supplied with the mating connector and 25cm tails; ViaLite part number 73953.
The connector and crimps are Molex 501646-1000 and 501647-1000 respectively should a user wish to derive
their own application.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
15
Receiver RLL AGC function
It is often desirable to have a constant RF over fibre analogue end-to-end link gain despite small changes in
optical path loss. With the AGC RLL function enabled, changes in optical Received Light Level are counteracted
with corresponding changes in RF gain. The end result is a consistent RF link gain regardless of optical path
loss. It should be noted however that when using RLL AGC, the following points apply:
RF Gain changes are in 0.5dB steps.
Hysteresis is applied to prevent gain oscillations.
An AGC gain target is required to be set for nominal RLL.
RF Gain control range is limited to 15.5dB.
RF Gain will limit at its maximum when RLL is very low compared to nominal.
RF Gain will limit at its minimum when RLL is very high compared to nominal.
Typical usage scenarios are as follows:
Switched optical path systems.
Long distance link with fibre path loss fluctuations due to fibre temperature changes or strain.
Link system over rented network suffering regular maintenance and reconfiguration.
2.6 Dual rack card variants
The chassis rack card variant supports dual channel configurations and the following rear panel connection
arrangements apply.
RF port A
OPTICAL port A
OPTICAL port B
RF port B
Port set
Dual TX
Dual RX
Transceiver
A
Transmitter 1
Receiver 1
Receiver
B
Transmitter 2
Receiver 2
Transmitter
2.7 USB CLI command and control
The Blue and Black OEM modules are fitted with a USB-C connector which when plugged into a PC, registers
as a serial COM port. This then delivers a command line interface (CLI) over a terminal application. There are
many terminal applications available, below is an example using the open-source PuTTY application.
https://www.putty.org/

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
16
A rubber bung is used to seal the USB-C socket on the black OEM which needs to be removed to allow
connection. This is a screw in bung and needs to be turned anti-clockwise to remove.
Connection configuration
The connection parameters are, as is fairly common:
9600 baud, 8 Data bits, 1 Stop bit, with no parity or flow control. Local echo ON.
Command set
The CLI command interface is implemented as SCPI (Standard Commands for Programmable Instruments).
The following conventions are implemented for convenience:
Commands are case insensitive.
For single RX system types, the RX1 prefix is optional.
For single TX system types, the TX1 prefix is optional.
For TRX system types, the path identifier, [1], is optional.
RX[1]|2:RF:GAIN
RX[1]|2:RF:GAIN?
RX[1]|2:RF:GAIN:RANGE?
RX[1]|2:RF:POWER?
RX[1]|2:OPTICAL:RLL?
RX[1]|2:BIAST:VOLTAGE
RX[1]|2:BIAST:VOLTAGE?
RX[1]|2:BIAST:CURRENT?

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
17
RX[1]|2:AGC <OFF>|<RLL>
RX[1]|2:AGC?
RX[1]|2:AGC:TARGET <float>
RX[1]|2:AGC:TARGET?
RX[1]|2:MONITOR
RX[1]|2:MONITOR?
TX[1]|2:RF:GAIN
TX[1]|2:RF:GAIN?
TX[1]|2:RF:GAIN:RANGE?
TX[1]|2:RF:POWER?
TX[1]|2:OPTICAL:POWER?
TX[1]|2:BIAST:VOLTAGE
TX[1]|2:BIAST:VOLTAGE?
TX[1]|2:BIAST:CURRENT?
TX[1]|2:AFD:ENABLE <ON>|<OFF>
TX[1]|2:AFD:ENABLE?
TX[1]|2:AFD:THRESHOLD
TX[1]|2:AFD:THRESHOLD?
TX[1]|2:MONITOR
TX[1]|2:MONITOR?
SYSTEM:VOLTAGE?
SYSTEM:VERSION?
SYSTEM:ERRORS?
SYSTEM:TEMPERATURE?
The full command set above with examples and expected return values are documented in a separate
document. Commands will be actioned immediately with no need to power cycle the system.
2.8 Rack card web interface via the HRC-3
The rack card variants of the link modules can be monitored and controlled via the HRC-3 web GUI and by
SNMP over the Ethernet interface supported in the HRK chassis.
Below is a screenshot of the web GUI for a dual transmitter.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
18
3 System integration
In order to integrate the link into a communication system, a full understanding of its performance is required.
This section will detail the various performance aspects and how they are affected by optical link length and
environmental effects such as temperature.
3.1 Link gain
The link gain is a combination of the transmitter gain, fibre loss and receiver gain. The transmitter and receiver
have gain controls to optimise performance when integrated with external user equipment.
Transmitter gain
The transmitter gain setting directly influences the Link noise figure and linearity so is used to optimise the
interface to the user signal source. There is 15dB of gain control available around the nominal default gain
delivered by the hardware.
The transmitter module is available in various gain versions to suit different markets. Higher gain versions have
extra amplifiers integrated and have a slightly higher power consumption as a result.
Fibre loss
The optical loss through the fibre and any other optical distribution components has a significant effect on the
performance of the link. The link end-to-end RF gain will drop 2dB for every 1dB of optical loss. It is therefore
crucial to ensure optical losses are minimised.
A well mated optical connection will give about 0.2dB of optical insertion loss so minimising the number of
connections is crucial. Wherever possible in the optical network, replace connections with splices to minimise
loss. All ViaLiteHD links are calibrated inclusive of their own connection loss so these don’t need to be
accounted for in user designs, only any additional connections.
Significant optical losses can also be created by stretching or bending optical fibre beyond its minimum bend
radius. Ensure the minimum bend radius is adhered to for the choice of single mode fibre in use.
Receiver gain
The receiver gain setting has only a very minor influence on link noise figure and linearity and is used mainly to
adjust the link output level to optimise the interface to the user signal sink equipment. There is 15dB of gain
control available around the nominal default gain delivered by the hardware.
For long distance links, care must be taken
when selecting the transmitter laser
wavelength. Standard SMF28 optical fibre has
a different loss profile per wavelength. The
data here is an example ZWP fibre from OFS.

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
19
Gain selection for optimum link performance
The following guide shows how to trade NF and Linearity using the transmitter gain control and link output power
using the receiver gain control for optimal interfacing with user equipment.
The various link configurations are shown in rows with reference data at both 1.5GHz and 5GHz.
SFDR 109.3 109.5 109.7 109.8 109.9 110.0 110.0 110.1 110.1 110.1 110.1 dB/Hz SFDR 102.1 102.2 102.3 102.4 102.4 102.5 102.5 102.5 102.5 102.6 102.6 dB/Hz
IP1 3.7 3.0 2.3 1.5 0.7 -0.1 -1.0 -1.9 -2.8 -3.7 -4.6 dBm IP1 2.6 2.0 1.3 0.5 -0.3 -1.1 -2.0 -2.8 -3.7 -4.7 -5.6 dBm
IIP3 15.0 14.3 13.5 12.7 11.9 11.0 10.2 9.3 8.3 7.4 6.4 dBm IIP3 11.4 10.6 9.7 8.8 7.9 7.0 6.0 5.1 4.1 3.1 2.1 dBm
NF 24.9 23.9 22.9 21.9 20.9 20.0 19.0 18.0 17.1 16.1 15.2 dB NF 32.1 31.1 30.1 29.1 28.1 27.1 26.1 25.1 24.1 23.1 22.2 dB
TX Gain (dB)
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5
TX Gain (dB)
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5
9-6 -5 -4 -3 -2 -1 0 1 2 3 4 9-6 -5 -4 -3 -2 -1 0 1 2 3 4
10 -5 -4 -3 -2 -1 0 1 2 3 4 5 10 -5 -4 -3 -2 -1 0 1 2 3 4 5
11 -4 -3 -2 -1 0 1 2 3 4 5 6 11 -4 -3 -2 -1 0 1 2 3 4 5 6
12 -3 -2 -1 0 1 2 3 4 5 6 7 12 -3 -2 -1 0 1 2 3 4 5 6 7
13 -2 -1 0 1 2 3 4 5 6 7 8 13 -2 -1 0 1 2 3 4 5 6 7 8
14 -1 0 1 2 3 4 5 6 7 8 9 14 -1 0 1 2 3 4 5 6 7 8 9
15 0 1 2 3 4 5 6 7 8 9 10 15 0 1 2 3 4 5 6 7 8 9 10
16 1 2 3 4 5 6 7 8 9 10 11 16 1 2 3 4 5 6 7 8 9 10 11
17 2 3 4 5 6 7 8 9 10 11 12 17 2 3 4 5 6 7 8 9 10 11 12
18 3 4 5 6 7 8 9 10 11 12 13 18 3 4 5 6 7 8 9 10 11 12 13
19 4 5 6 7 8 9 10 11 12 13 14 19 4 5 6 7 8 9 10 11 12 13 14
20 5 6 7 8 9 10 11 12 13 14 15 20 5 6 7 8 9 10 11 12 13 14 15
21 6 7 8 9 10 11 12 13 14 15 16 21 6 7 8 9 10 11 12 13 14 15 16
22 7 8 9 10 11 12 13 14 15 16 17 22 7 8 9 10 11 12 13 14 15 16 17
SFDR 107.6 107.8 108.0 108.0 108.0 107.9 107.8 107.5 107.3 106.9 106.5 dB/Hz SFDR 101.4 101.5 101.7 101.8 101.9 102.0 102.0 102.0 101.9 101.9 101.8 dB/Hz
IP1 -10.9 -11.5 -12.2 -12.9 -13.7 -14.5 -15.3 -16.2 -17.0 -18.0 -18.9 dBm IP1 -11.8 -12.4 -13.0 -13.7 -14.4 -15.1 -15.9 -16.8 -17.6 -18.5 -19.4 dBm
IIP3 -0.8 -1.3 -1.9 -2.5 -3.2 -3.9 -4.6 -5.4 -6.3 -7.1 -8.0 dBm IIP3 -3.3 -4.0 -4.7 -5.5 -6.3 -7.1 -8.0 -8.9 -9.8 -10.7 -11.7 dBm
NF 11.6 10.8 10.1 9.4 8.7 8.1 7.6 7.1 6.7 6.3 6.0 dB NF 18.5 17.6 16.6 15.6 14.7 13.8 12.9 12.0 11.1 10.3 9.5 dB
TX Gain (dB)
-1 0 1 2 3 4 5 6 7 8 9
TX Gain (dB)
-1 0 1 2 3 4 5 6 7 8 9
98 9 10 11 12 13 14 15 16 17 18 98 9 10 11 12 13 14 15 16 17 18
10 910 11 12 13 14 15 16 17 18 19 10 910 11 12 13 14 15 16 17 18 19
11 10 11 12 13 14 15 16 17 18 19 20 11 10 11 12 13 14 15 16 17 18 19 20
12 11 12 13 14 15 16 17 18 19 20 21 12 11 12 13 14 15 16 17 18 19 20 21
13 12 13 14 15 16 17 18 19 20 21 22 13 12 13 14 15 16 17 18 19 20 21 22
14 13 14 15 16 17 18 19 20 21 22 23 14 13 14 15 16 17 18 19 20 21 22 23
15 14 15 16 17 18 19 20 21 22 23 24 15 14 15 16 17 18 19 20 21 22 23 24
16 15 16 17 18 19 20 21 22 23 24 25 16 15 16 17 18 19 20 21 22 23 24 25
17 16 17 18 19 20 21 22 23 24 25 26 17 16 17 18 19 20 21 22 23 24 25 26
18 17 18 19 20 21 22 23 24 25 26 27 18 17 18 19 20 21 22 23 24 25 26 27
19 18 19 20 21 22 23 24 25 26 27 28 19 18 19 20 21 22 23 24 25 26 27 28
20 19 20 21 22 23 24 25 26 27 28 29 20 19 20 21 22 23 24 25 26 27 28 29
21 20 21 22 23 24 25 26 27 28 29 30 21 20 21 22 23 24 25 26 27 28 29 30
22 21 22 23 24 25 26 27 28 29 30 31 22 21 22 23 24 25 26 27 28 29 30 31
SFDR 109.4 109.5 109.7 109.8 109.9 109.9 110.0 110.0 110.0 110.0 110.0 dB/Hz SFDR 102.0 102.1 102.2 102.3 102.3 102.3 102.4 102.4 102.4 102.4 102.4 dB/Hz
IP1 3.3 2.7 1.9 1.1 0.3 -0.5 -1.4 -2.3 -3.2 -4.2 -5.1 dBm IP1 2.3 1.6 0.9 0.1 -0.7 -1.5 -2.4 -3.3 -4.2 -5.1 -6.1 dBm
IIP3 14.7 13.9 13.1 12.3 11.5 10.6 9.7 8.8 7.9 6.9 6.0 dBm IIP3 11.2 10.4 9.5 8.6 7.7 6.7 5.8 4.8 3.9 2.9 1.9 dBm
NF 24.5 23.5 22.5 21.5 20.6 19.6 18.6 17.7 16.7 15.8 14.8 dB NF 32.1 31.1 30.1 29.1 28.1 27.1 26.1 25.1 24.1 23.1 22.1 dB
TX Gain (dB)
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5
TX Gain (dB)
-15 -14 -13 -12 -11 -10 -9 -8 -7 -6 -5
15 0 1 2 3 4 5 6 7 8 9 10 15 0 1 2 3 4 5 6 7 8 9 10
16 1 2 3 4 5 6 7 8 9 10 11 16 1 2 3 4 5 6 7 8 9 10 11
17 2 3 4 5 6 7 8 9 10 11 12 17 2 3 4 5 6 7 8 9 10 11 12
18 3 4 5 6 7 8 9 10 11 12 13 18 3 4 5 6 7 8 9 10 11 12 13
19 4 5 6 7 8 9 10 11 12 13 14 19 4 5 6 7 8 9 10 11 12 13 14
20 5 6 7 8 9 10 11 12 13 14 15 20 5 6 7 8 9 10 11 12 13 14 15
21 6 7 8 9 10 11 12 13 14 15 16 21 6 7 8 9 10 11 12 13 14 15 16
22 7 8 9 10 11 12 13 14 15 16 17 22 7 8 9 10 11 12 13 14 15 16 17
23 8 9 10 11 12 13 14 15 16 17 18 23 8 9 10 11 12 13 14 15 16 17 18
24 910 11 12 13 14 15 16 17 18 19 24 910 11 12 13 14 15 16 17 18 19
25 10 11 12 13 14 15 16 17 18 19 20 25 10 11 12 13 14 15 16 17 18 19 20
26 11 12 13 14 15 16 17 18 19 20 21 26 11 12 13 14 15 16 17 18 19 20 21
27 12 13 14 15 16 17 18 19 20 21 22 27 12 13 14 15 16 17 18 19 20 21 22
28 13 14 15 16 17 18 19 20 21 22 23 28 13 14 15 16 17 18 19 20 21 22 23
MilAero 10MHz-6GHz RFoF: Unity link
1.5 GHz
MilAero 10MHz-6GHz RFoF: Unity link
5 GHz
Nominal RX Gain (dB)
Available link gains (dB)
Nominal RX Gain (dB)
Nominal RX Gain (dB)
Available link gains (dB)
Nominal RX Gain (dB)
Available link gains (dB)
MilAero 10MHz-6GHz RFoF: High Gain link
1.5 GHz
MilAero 10MHz-6GHz RFoF: High Gain link
5 GHz
Nominal RX Gain (dB)
Available link gains (dB)
Nominal RX Gain (dB)
Available link gains (dB)
Available link gains (dB)
MilAero 10MHz-6GHz RFoF: High Output link
1.5 GHz
MilAero 10MHz-6GHz RFoF: High Output link
5 GHz

MIL-AERO 10MHZ TO 6GHZ RF LINK HANDBOOK
20
3.2 Frequency response
The link frequency response is fairly flat from 10MHz
to 6GHz typically < +/- 1 dB. Usable gain is present
up to 7GHz.
3.3 VSWR
The VSWR of the transmitter input and receiver
output is generally better than 1.4.
3.4 Noise Figure
The Noise figure can be traded with linearity using
the transmitter gain settings to best suit the
application. The measurement here is from a link
incorporating the high gain transmitter. The noise
figure of the link increases with frequency as a result
of the laser technology so must be considered when
selecting the gain.
Noise figure vs link loss
The Noise figure degrades with increasing link loss.
In the high gain link measurement shown adjacent,
the noise figure increases slowly for the first 4-5 dB
of optical loss and then increases 2:1 with optical
loss. Minimising link loss is crucial to maintain best
performance.
10
11
12
13
14
15
16
17
18
19
20
0 1 2 3 4 5 6 7
Link Gain (dB)
Frequency (GHz)
MilAero Link Gain
High Gain 2.5mW TX
1.00
1.10
1.20
1.30
1.40
1.50
1.60
1.70
1.80
1.90
2.00
0 1 2 3 4 5 6 7 8 9
VSWR
Frequency (GHz)
MilAero Link VSWR
Tx Input
Rx Output
0
5
10
15
20
25
30
35
0 1000 2000 3000 4000 5000 6000 7000 8000
Noise Figure (dB)
Frequency (MHz)
MilAero link: Noise Figure
0
5
10
15
20
25
30
35
40
45
0 2 4 6 8 10 12 14 16 18 20
Noise Figure (dB)
Optical link loss (dB)
Milaero Link NF vs Link optical loss (3GHz)