OMB MT-MR PLATINUM User manual

O.M.B. SISTEMAS ELECTRONICOS, S.A.
POINT TO POINT
AURAL RADIO RELAY
SYSTEM
M MT T- -M MR R
PLLAATTIINNUUMM
TECHNICAL
MANUAL
Head Offices:
Avda. San Antonio, 41.
50410 Cuarte de Huerva.
Zaragoza, Spain.
Phones: (976) 50-4696 six lines
Fax: [phone]
e-mail:[email protected]
Webpage: http:// www.omb.com
International Division:
3100 N.W. 72nd. Ave. #112.
Miami, FL 33122. U.S.A.
Phones: [phone] six lines
[phone]
Fax: [phone]
e-mail: [e-mail]
Factories:
Camino de los Albares, 14 bajos.
50410 Cuarte de Huerva.
Zaragoza, Spain.
Phone: [phone] six lines
Fax: [phone]

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
1
LimitedWarrantyConditions
I.- About Installation.
1.- Mains Voltage must be kept between ± 10% about its nominal value, unless otherwise specified. If were variations exceeding this tolerance, it will be indispensable
to install a voltage stabilizer system within station. If transient overvoltages, due to electric motors, or other devices of this sort connected to the distribution line, were
present, or if the distribution line is exposed to atmospheric electrical discharges, it must be indispensable the installation of isolation transformers and gaseous
dischargers before connecting any equipment within station.
2.- All equipments must be connected to station ground system in order to avoid damage both to equipments and maintenance personnel too. It is necessary to connect a
differential automatic switch (lifesaver) at station.
3.- Some equipments does not include interlock protection for open doors, covers or connectors. In that case, these equipments must be kept in key-locked places, with access
only to conveniently qualified personnel that is previously noticed about not to open doors, covers or connectors without disconnecting station mains switch before performing
this job.
4.- Transmitter equipments NEVER will be operated with output powers over its nominal values, or with signals or input informations others than those specified in its individual
characteristics.
5.- Ambient temperature inside equipments' room, will accomplish technical specifications of equipments installed at station lodge. In absence of such specifications,maximum
allowable temperatures will be from -5 to + 45 º C for Television equipments, and from 0 to + 40 º C for Sound Broadcast equipments.
6.- In case of operation at abnormally high or extremely high temperatures (over 30 to 40 º C), it is obligatory to install a forced cooling system that will keep temperature below
its upper limit. In case of operation at abnormally or extremely low temperatures, it will be obligatory to install a thermostatic controlled heating system for equipment's room.
7.- Both equipment's surroundings and room must be free of dust and dirt. Ambient relative humidity will be kept below equipment's extreme specifications. In case of absence
of this specification, allowable maximum will be 90 % of relative humidity, non-condensing. Average relative humidity will be kept under 70 %, non-condensing.
8.- Every transmission equipment that can radiate some quantity of RF power, must be connected to a load or antenna system, suited to its individual specifications, before
being energized.
9.- Maximum allowable VSWR in antenna systems both for Television or FM Radio Broadcast operation of a given transmitter, will be 1.25:1, unless otherwise specified.
10.- For those transmitter equipments having power valve amplifiers, and that doesn't has an automatic shutoff cycle, and must be manually turned off, as a first step high
voltage, or anode voltage, will be disconnected, keeping forced cooling system working during at least 5 minutes after high voltage disconnection, and only after this time,
cooling system & filament voltage can be shutted off. O.M.B. Sistemas Electrónicos, S.A., is not responsible of damages to those power valves caused by sudden AC mains
failures at station where our equipments are installed.
11.- Periodically, monthly as a maximum, technical personnel must visit station in order to perform a general equipment maintenance, unless otherwise specified. This
maintenance will include output power check, VSWR of antenna systems, forced cooling or heating systems checks, both for equipments and station itself, including air filters
cleaning, measuring of transmission frequency with eventual correction if necessary, and will perform a general check of fundamental parameters of equipments. In the event
of any important change in some operation parameter, that will require replacement or readjustment of any unit, Customer MUST CONTACT FIRST WITH O.M.B.
SISTEMAS ELECTRONICOS, S.A. BEFORE ANY ATTEMPT TO READJUST OR REPLACE ANY COMPONENT OR UNIT INSIDE EQUIPMENTS, IN ORDER TO KEEP
VALID THIS WARRANTY.
12.- For equipments who are located in fixed racks or cabinets, those equipments must be effectively connected, according to International Installations Standards, to
station ground system, whose total impedance measured to ground can't be higher than 5 ohms. Equipments must be connected to ground system so that they can be kept out
of main discharge path between tower and ground.
II.- About Transportation.
1.- O.M.B. Sistemas Electrónicos, S.A. is not responsible of damages and/or detriments derived from mishandling, steal, robbery, theft or vandalism during the act of
transportation of equipments to final or intermediate destination.
III.- About Storage.
1.- O.M.B. Sistemas Electrónicos, S.A. is not responsible of damages and/or detriments derived from unappropiate storage of equipments, within inadequate warehouses or
outdoors, once equipments are delivered to transportist agency.
IV.- About Projects.
1.- O.M.B. Sistemas Electronicos, S.A. is not responsible of inadequate use of equipments made or registered by our Company, accomplishing propagation projects that are
not performed by our Specialists.
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MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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V.- About Systems.
1.- O.M.B. Sistemas Electrónicos, S.A. is not responsible for performance of those equipments or systems that are not made, certified or registered by our Company.
VI.- About Operation
1.- O.M.B. Sistemas Electrónicos, S.A. is not responsible of damages and/or detriments derived from inadequate or negligent operation of equipments made, certified or
registered by our Company, once those equipments are operated by personnel hired and/or employed by Customer.
VII.- General.
This Warranty covers and protects, during a period of 18 months after start of operations, all equipments made , certified or registered by O.M.B. Sistemas Electrónicos, S.A.,
including its components and units, against failures in workmanship that may occur during operation of those equipments, with the exception of power valves or
semiconductor devices that are covered by its particular Factory's Guarantee. In this case, O.M.B. Sistemas Electrónicos, S.A. only can act as intermediary for negotiation with
such Factory, about accomplishment of individual Guarantees.
For Validity of this Warranty, it is indispensable that all Paragraphs, from I to VI, be respected by the Customer. Otherwise, this Warranty will be automatically voided. This
Warranty is self-activated with the reception by OMB Sistemas Electrónicos, S.A. of the "Guarantee Activation Manual". returned to OMB by Customer. If such Document is not
received, this Warranty will be voided.
All repairings or adjustments covered by this Warranty are free of workmanship & materials costs and expenses, but postage and transportation expenses of equipments and
O.M.B. technical personnel & specialists, if required, will be carried out by the Customer.
O.M.B. Sistemas Electrónicos, S.A.
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MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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GENERAL SAFETY RECOMMENDATIONS
When connecting any OMB equipment to the Mains power , please follow these important recommendations:
!"
This product is intended to operate from a power source that will not apply more than 10% of the voltage
specified on the rear panel between the supply conductors or between either supply conductor and ground.
A protective-ground connection by way of the grounding conductor in the power cord is essential for safe
operation.
!"
This equipment is also grounded through the grounding conductor of the power cord. To avoid electrical
shock, plug the power cord into a properly wired socket before connecting to the product input or output
terminals.
!"
Upon loss of the protective-ground connection, all accessible conductive parts (including parts that may
appear to be insulating) can render an electric shock. Equipment must be throughly connected to Station's
ground system before any attempt to connect it to Mains electrical supply.
!"
To avoid fire hazard, use only the fuses of correct type, voltage rating, and current rating. Refer fuse
replacement to Technical Manual and qualified service personnel.
!"
To avoid explosion, do not operate this equipment in an explosive atmosphere.
!"
To avoid personal injury, do not remove the product covers or panels. Do not operate the product without
the covers and panels properly installed.
GOOD PRACTICES
In maintaining the equipment covered in this Manual, please keep in mind the following, standard good practices:
!"
When connecting any instrument (wattmeter, spectrum analyzer, etc.) to a high frequency output, use the
appropriate attenuator or dummy load to protect the final amplifiers and the instrument input.
!"
When inserting or removing printed circuit boards (PCBs), cable connectors, or fuses, always turn off power to
the affected portion of the equipment. After power is removed, allow sufficient time for the power supplies to
bleed down before reinserting PCBs. Always use discharge stick when available.
!"
When troubleshooting, remember that FETs and other metal-oxide semiconductor (MOS) devices may appear
defective because of leakage between traces or component leads on the printed circuit board. Clean the printed
circuit board and recheck the MOS device before assuming it is defective.
!"
When replacing MOS devices, follow standard practices to avoid damage caused by static charges and
soldering.
!"
When removing components from PCBs (particularly ICs), use care to avoid damaging PCB traces.
FA-1

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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FIRST AID IN CASE OF ELECTRICAL SHOCK
If someone seems unable to free himself while receiving an electric shock, turn power off before rendering aid. A
muscular spasm or unconsciousness can make a victim unable to free himself from the electrical power.
If power cannot be turned off immediately, very carefully loop a length of dry non-conducting material (such
as a rope, insulating material, or clothing) around the victim and pull him free of the power. Carefully avoid touching
him or his clothing until free of power.
EMERGENCY RESUSCITATION TECHNIQUE
Step 1
Check the victim for unresponsiveness. If there is no response, immediately call for
medical assistance, and then return to the person.
Step 2
Position the person flat on their back. Kneel by their side and place one hand on the
forehead and the other under the chin. Tilt the head back and lift the chin until teeth almost
touch. Look and listen for breathing.
Step 3
If not breathing normally, pinch the nose and cover the mouth with yours. Give two full
breaths. The person's chest will rise if you are giving enough air.
FA-2
DO NOT TOUCH VICTIM OR HIS CLOTHING
BEFORE POWER IS DISCONNECTED OR YOU
CAN ALSO BECOME A SHOCK VICTIM

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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Step 4
Put the fingertips of your hand on the Adam's apple, slide them into the groove next to the
windpipe. Feel for a pulse. If you can not feel a pulse or are unsure, move on to the next
step.
Step 5
Position your hands in the center of the chest between the nipples. Place one hand on top of
the other.
Step 6
Push down firmly two inches. Push on chest 15 times.
CONTINUE WITH TWO BREATHS AND 15 PUMPS UNTIL HELP ARRIVES.
TREATMENT FOR BURNS
!"
Continue treating victim for electrical shock.
!"
Check for points of entry and exit of current.
!"
Cover burned surface with a clean dressing.
!"
Remove all clothing from the injured area, but cut around any clothing that adheres to the skin and leave it in
place. Keep the patient covered, except the injured part, since there is a tendency to chill.
!"
Splint all fractures. (Violent muscle contractions caused by the electricity may result in fractures.)
!"
Never allow burned surfaces to be in contact with each other, such as: areas between the fingers or toes, the
ears and the side of the head, the undersurface of the arm and the chest wall, the folds of the groin, and similar
places..
!"
Transport as soon as possible to a medical facility.
FA-3

MT-MR PLATINUM. POINT TO POINT AURAL RADIO RELAY SYSTEM
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MT-MR PLATINUM
POINT TO POINT AURAL RADIO RELAY SYSTEM
T
TA AB BL LE E O OF F C CO ON NT TE EN NT TS S
Chapter Description Page
I.- ...................................................................................... Previous Path Calculations .................................................................................................... 7
1.1.- Introduction ...................................................................................................................... 7
1.2.- Free Space Attenuation ................................................................................................... 7
1.3.- Path Profile Analysis ....................................................................................................... 8
1.4.- Fresnel or Phase Zones ..................................................................................................10
1.5.- Transmission Lines ..........................................................................................................13
1.6.- Calculation of Antennas ...................................................................................................14
1.7.- Parameters of Interest in Link Analysis.......................................................................... 16
II.- ......................................................................................General System Description .................................................................................................... 19
2.1.- Introduction ..................................................................................................................... 19
2.2.- System Technical Specifications ................................................................................... 21
III.- ..................................................................................... The MT Platinum Link Transmitter ......................................................................................... 22
3.1.- Description ..................................................................................................................... 22
3.2.- Transmitter Technical Specifications ............................................................................ 23
3.3.- Audio Processor Unit ...... ............................................................................................. 25
3.4.- VCO & PLL Unit ............................................................................................................ 25
3.5.- Microcontroller or Control Unit & Attached Display ....................................................... 26
IV.- ..................................................................................... The MR Platinum Link Receiver ............................................................................................ 27
4.1.- Description .................................................................................................................... 27
4.2.- Technical Specifications .............................................................................................. 28
4.3.- Receiver Performance......................... ........................................................................ 30
V.- ........................................................................................ Installation and Operation of Aural Link ............................................................................... 32
5.1.- Installation and Checks................................................................................................. 32
5.2.- Operation and Maintenance ....................................................................................... 35
VI.- ....................................................................................... Lists of Parts & Components. Schematics ........................................................................... 36
Appendix I……………………………………………………..... Polarization voltages and currents in the amplifiying modules of MT Platinum
-------------o0o--------------

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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MT-MR PLATINUM
POINT TO POINT AURAL RADIO RELAY SYSTEM
chapter I
PREVIOUS PATH CALCULATIONS.
1.1.- Introduction
As a preliminary knowledge, it's necessary to calculate what is the type of link we need to buy in order to solve our
particular case, or if we have a certain set of equipments and antennas previously adquired, what are the
capabilities of that system to cover the planned distance with the minimum required signal strength in order to assure a
long-term, noise-free transmission of video and /or audio information through this way. Prior to install a certain
system, Engineers have to perform some preliminary calculations to guarantee that these results will be reached.
Main factors determining the reliability of a certain Microwave analogic link are the following, particularly in the
bands starting from 1 GHz and ending in 12 GHz :
1.1.1.- Free Space Attenuation of propagated RF signal.
1.1.2.- Presence of obstructions in the propagation path.
1.1.3.- Possible Reflection Points of propagated signal.
1.1.4.- Transmission lines and antennas used in the system.
1.1.5.- Any other RF elements and components installed through the transmission path, such as filters,
circulators, diplexers, etc. attenuating in a higher or lower degree the propagated signal strength.
1.1.6.- Transmitter power output and receiver sensitivity & noise figure.
1.1.7.- Propagation path free space clearance at radio waves frequency.
Through this Introductory Study, we should briefly talk about these factors determining the behavior of any Analogic
Radio Relay Link:.
1.2.- Free Space Attenuation.
Atmospheric or Free Space Attenuation within the direct path between Transmitter and Receiver sites, is a function
of the system transmission frequency and the distance between both sites. This expression is affected by a
coefficient depending on the Earth's region where the link will be installed, and is determined by estatistical
calculations in an empirical form :

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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( 1) α= K + 20 log10f + 20 log10d [dB]
Where:
α= Free Space Attenuation in dB.
f = System frequency in MHz.
d = Straight-line distance between Transmitter & Receiver, in Km.
K = Attenuation Coefficient:
K = 37.83 for Region I.
K = 32.58 for Region II.
K = 33.03 for Region III.
NOTE : Values of K are average values, and can suffer local appreciable variations
depending on the atmospheric conditions of a particular climate.
In order to illustrate the calculations performed, we can apply this and the following expressions to an
hypotetical link of any frequency band, say of the 2 GHz band. Assuming two points distant 32 Km., located at
Radio Propagation Region II. Suppose that assigned frequency is 2038 MHz (Channel V of 1.9 to 2.3 GHz Band). If we
substitute values in Expression (1) , we have:
If f = 2038 MHz
d = 40 Km
K = 32.58
Hence: α= 32.58 + 20 log (2038) + 20 log(40)
Solving: α= 130.9 dB
It's very interesting to arrive to a conclussive judgement with respect to Expression (1) :
"Free Space Attenuation between two points increases logarithmically with the frequency used and with the
distance between the two points considered".
1.3.- Path Profile Analysis.
In order to analyze Terrain's profile along propagation path, in first place we must obtain the Topographic Charts at
1:50,000 covering the whole intermediate region between the two considered points. If it's required, two or more
charts would be joined together at its ends, using transparent tape, to assemble the complete terrain's profile in the
region of interest.
Once Topographic Chart is assembled, it will be covered with a transparent sheet in order to preserve that maps
are not marked. Now we trace a straight line joining Transmitter and Receiver points, and using a rule marked in
Km in the same scale of the Charts used, we mark the distance between the two points in one kilometer (or mile)
intervals, obtaining the true straight-line distance between the two points, as shown in the Fig. # 1 below :

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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Once path is appropiately traced and marked as shown in Fig.#1, we obtain the straight-line distance between
Transmitter point (A) and Receiver point (B), this being in our example exactly 40 Km.
Now we take a 4/3 Profile Sheet. This is a special printed paper having approximately the same curvature radius of
the Earth at frequencies beyond 500 MHz over the horizontal axis. This axis is calibrated in Km (or miles). By the
other hand, vertical axis is calibrated in meters (or feet) to mark the height of terrain at the different points of a
certain path. Curvature of horizontal axis is made indeed in order to represent the propagated beam as a straight
line traced between Transmitter and Receiver points. This virtual radius can considerably change for abnormal
conditions of the lower layers of atmosphere, provoking an undesirable phenomenon known as "beam bending
fading" that deviates beam up or downwards, according with the variation of atmosphere's reffraction index.
In this Profile Sheet, we mark now all heights, from one kilometer to the next one, along our propagation path AB,
as shown in Fig. #2, following the horizontal-axis marks previously made along the propagation path AB in Fig. #1.
The next step is to trace a straight line joining the points A and B in the Profile Sheet, taking into account the height
of antennas over terrain at both terminal points.
As said in the note of Fig. #2, remember that, if it were required to widen horizontal scale for long hops, this scale
can be duplicated, but always multiplying by four the vertical scale in order to keep the same proportions in the
paper. Otherwise, the drawn profile is not valid. The same is valid for the profile made in miles and feet.
8
0
0
700
600
500
500
500
400
300
200
100
100
RIVER
200
300
400
500
600
700
800 900
10
20
30
40 Km
Fig.#1. TOPOGRAPHIC CHART WITH PATH BETWEEN STATIONS MARKED FOR CALCULATIONS

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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Fig. # 2. PATH MARKED IN 4/3 PROFILE PAPER SHEET.
1.4.- Fresnel or Phase Zones.
Wave front propagated by transmitting antenna is going out of phase as propagated wave goes apart from
the beam center more and more in a continuous fashion. The limits of phase shift suffered by this propagated wave
front, as it separates from the beam center, are known as "Fresnel or Phase Zones" being these zones enclosed
between well defined values like π/2, π, 3π/2, etc, and defined as follows:
First Fresnel Zone is those region where wavefront is shifted in phase from 0º (beam center) to 90º. It encloses
about 70% of the total beam RF energy density. It's very important in any hop to get a total clearance, non-
obstructed path for this region. As system frequency drops down, propagated energy density enclosed in this zone
increases, and in the 2 GHz band it's required to release only 70% of the total beam area at First Fresnel Zone in
any obstructed point along the propagation path. For upper frequency bands, starting in 4 GHz, First Fresnel Zone
clearance must be total (100%) in order to assure a nominal signal strength at the receiving end.
Second Fresnel Zone is those region where wavefront is phase-shifted from 90º to 180º. Is obvious that this zone
should be blocked out wherever it's possible along the propagation path, because it contributes to weaken the
signal at receiving end if it's reflected over the center beam line at any point of the path. In the third, fourth, etc
Zones, energy density is very weak and it can be considered as negligible.

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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Fig. 3. DISTRIBUTION OF FIRST & SECOND FRESNEL ZONES ALONG PATH
As can be seen above in Fig. #3, higher order Fresnel Zones are distributed in concentric rings over the First Zone
along the propagation path. When planning flat-terrain links, it will be relatively easy to block the Second Zone and
completely clearing the First Zone, but in some hops, particularly those located between high mountains, it will be
not possible. In these cases, a complete clearing of both Zones should be allowed.
Radius of any Fresnel Zone at any point of intermediate path can be easily determined by the following expression:
d1. d2
(2) R(n) = 31.6 n. λ
d3
Where:
R(n) = Radius (in meters) of a Fresnel Zone of nth. Order.
n = Order of the Fresnel Zone considered.
λ= Wavelength of propagated signal. λ[meters] = 300/f [MHz]
f = Carrier signal frequency (MHz).
d1= Distance from Transmitter point (A) to
considered point (X). [Km]
d2 = Distance from considered point (X) to Receiver point (B). [Km]
d3= Total distance from A to B. [Km]

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
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Distances can be seen in the following Fig. # 4:
Fig. 4. DISTANCES FOR CALCULATION OF FRESNEL ZONES RADII.
In our illustrative Example, we can find the radius of the First Fresnel Zone in the point where it assumes a
maximum value, in the path midpoint between A and B.
Data: Wavelength of propagated signal will be:
f = 2038 MHz
d1= 20 Km λ= 300/2038 = 0.147 m
d2= 20 Km
d3= 40 Km
n = 1 Inserting numerical values in Expression (2) :
R(1) = 31.6 (0.147 x (20 x 20)/40) ½
R(1) = 38.3 meters
Now we can calculate and trace, from one kilometer to the next, the radius of First Fresnel Zone for the whole
propagation in the Profile Sheet shown in Fig. # 2, giving the results shown below, in Fig. # 5:
Fig. 5. FIRST FRESNEL ZONE FOR ILLUSTRATIVE EXAMPLE IN 2 GHz BAND
This profile, as can be seen, has absolute clearance both for First and Second Fresnel Zones because it's a typical
inter-mountain hop. In case of partially obstructed profiles, it's allowable a clearance of 70% of total area at
X

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
13
obstructed point,but only in this frequency band. As we said before, at higher frequencies the clearance must be
100% for First Fresnel Zone.
Given these values here obtained, it's very easy for Engineer to visually calculate its optimal antenna height at both
points, A & B, also calculating the total length of transmission line needed for both ends, and its total line losses.
For calculating antenna heights over terrain, some elementary rules should be followed:
1.- In case of dealing with a link to be installed in a completely flat terrain, mainly in deserts, sugar cane
plantations, across big lakes or over sea water, location of both antennas (transmitting & receiving) at the
same height must be avoided, in order to move the possible reflection point from path's middle region. In this
case, an "up-to-down" hop is desirable and convenient in order to increase link's reliability.
2.- Always try to release the First Fresnel Zone to a maximum, blocking as much as possible the Second Fresnel
Zone.
3.- Use the minimum tower height allowable at both ends to satisfy the link's requirements, in order to minimize
transmission line length (and losses), unless you are planning to use periscopic reflectors in your link.
4.- In all cases, try to move the possible beam reflection point from the center of path, arranging antennas' heights to
avoid the reception of reflected signals under normal atmospheric conditions.
1.5.- Transmission Lines.
There are a wide variety of both coaxial transmission lines and waveguides in the International market for use in
any frequency band. Coaxial lines are used particularly at 1.9-2.3 GHz frequency band, and waveguides are
employed at higher frequencies, from 4 GHz ahead.
For links using the 1.9-2.3 GHz band, it's advisable the use of the 7/8" diameter coaxial foam-dielectric line, such as
Andrew LDF5-50A. This also avoids the use of bulky and expensive air compressors or nitrogen tanks to pressurize
the lines. If required transmission line is quite long, lower loss air-dielectric HJ5-50A line should be employed, and
pressurization will be required in this case. But this is advisable only in extreme and critical cases. Generally the
LDF5-50A (or equivalent) will satisfy the attenuation and power requirements in the most cases.
This typical transmission line has the following specifications:
Attenuation at 2 GHz ........................................................................................................................ 6.46 dB x 100 m.
Characteristic Impedance ............................................................................................................................. 50 ohms.
Maximum Allowable Frequency ....................................................................................................................... 5 GHz.
Velocity Factor ..................................................................................................................................................... 89%
Maximum Peak Power ..................................................................................................................................... 44 kW.
DC Resistance:
Inner Conductor ................................................................................................................. 1.15 ohms/1000 m.
Outer Conductor ..................................................................................................................1.18 ohms/1000 m.
DC Breakdown Voltage ........................................................................................................................................ 6 kV.
Capacitance ................................................................................................................................................... 75 pF/m.
Inductance ................................................................................................................................................ 0.187 µH/m.

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
14
Materials:
Inner Conductor ..................................................................................................................................... Copper.
Outer Conductor .................................................................................................................................... Copper.
Diameter (incl. PVC sheat) ............................................................................................................................... 28 mm.
Diameter (Outer cond.) .................................................................................................................................. 24.9 mm.
Minimum Bending Radius ............................................................................................................................... 250 mm.
Minimum Number of Bendings ................................................................................................................................. 15
Bending Momentum ...................................................................................................................................... 16.3 N/m.
Weight ......................................................................................................................................................... 0.49 Kg/m.
Resistance to Stress ........................................................................................................................................ 147 Kg.
Resistance to Crush .................................................................................................................................. 1.4 Kg/mm.
Any authorized Antennas Catalog contains these and other Technical Specifications in event of using other type of
transmission line. This is only an example of a possible use of a certain type of transmission line.
In our illustrative example, if we use two turrets having 20 m. height each, we have 20 meters of transmission line
length, plus additional 10 meters calculated to acceed the Station site and internal runways within Station building.
Total = 30 meters representing a loss of :
30 x 6.46
AL = = 1.94 dB [per Station]
100
By the other hand, it's allowable to assume 1 dB per station for connectors & coupling losses, so we have 2.94 dB
of total line & connector losses per station.
1.6.- Calculation of Antennas.
Final system calculation is the required Antenna gain at each Station in order to keep the link's reliability and
received signal level.
Assuming that we have a Transmitter Power output of 4 watts, that is +36 dBm, and following signal path from
Transmitter output to Receiver input, we can build the following expression:
(3) Pt - Alt+con. + Gat - ß + Gar - A lr+con. = Srec.
Where:
Pt = Transmitter Power Output in dBm (or dBw)
Alt+con. = Transmission line & connectors losses at Transmitter end.
(in dB).
Gat = Transmitter antenna gain (in dBi)
Page 8
ß = Free Space Attenuation (in dB)

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
15
Gar = Receiver antenna gain (in dBi)
Air+con.= Transmission line & connectors losses at Receiver end.
(in dB).
Srec. = Received Signal (in dBm or dBw)
In our illustrative Example, we can replace these parameters by its numerical values in Expression ( 3) :
+36 - 2.94 + Gat - 130.9 + Gar - 2.94 = Srec.
That is: Gat + Gar - 100.8 = Srec.
Lets choose our parabolic antennas having the same gain (and diameter) both in Transmitter & Receiver ends, so
Gat = Gar = Gant.
We have: 2 Gant. - 100.8 = Srec.
Analysis of this expression leads to a direct relationship between antennas' gain and Received Signal strength. This
is a commonly used trick to calculate in a safe and easy way the required antenna's diameter.
Now, we proceed to calculate the required minimum signal strength at receiver input. For performing this, we go to
the concept of Fade Margin, defined as the difference in dB existing between the nominal received signal and
receiver noise threshold. This Fade Margin, under normal conditions, should be kept at least at 40 dB (the higher
the better). So, the minimum required signal level at Receiver input will be:
(4) Srec. = Sthr. + FM
Assuming that our receiver has a Noise Threshold signal level of -80 dBm, we substitute the numerical values in
(4):
Srec. = -80 +40 = -40 dBm.
This value of -40 dBm will be the minimum required signal strength at Receiver's end in order to assure a reliable
value of signal-to-noise ratio in the received signal.
Replacing this value in the expression relating received signal strength with antennas' gain we have the following:
2 Gant. - 100.8 = -40
or : 2 Gant. = 60.8 dBi
Concluding: Gant. = 30.4 dBi
The next step is to consult any table of Parabolic Antennas in order to find the required diameter in our parabolic
reflectors to obtain this gain at the system working frequency. At 2 GHz band, mesh reflector antennas are widely
used, both for lighter weight and less wind load, taking into account the relatively large diameters required. An
example of these mesh antennas Table is as follows:

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
16
GAIN OF ANDREW® MESH PARABOLIC REFLECTORS
Reflector Gain at 1.9/2.3 GHz Frequency Band.
Diameter (dBi)
(m) 1.9 GHz 2.0 GHz 2.1 GHz 2.2 GHz 2.3 GHz
0.6 18.2 18.7 19.0 19.5 19.9
0.7 19.6 20.0 20.5 20.9 21.3
0.8 20.8 21.2 21.6 22.0 22.4
0.9 21.9 22.2 22.7 23.0 23.6
1.0 22.9 23.1 23.7 24.0 24.4
1.2 24.2 24.9 25.2 25.7 26.1
1.4 25.8 26.2 26.7 27.0 27.5
1.5 26.3 26.9 27.2 27.8 28.0
1.8 28.0 28.5 28.9 29.3 29.8
2.0 29.0 29.4 29.9 30.1 30.6
2.4 30.6 31.0 31.5 31.9 32.1
2.5 30.9 31.3 31.8 32.1 32.8
2.8 31.9 32.5 32.9 33.2 33.7
3.0 32.5 33.0 33.5 33.9 34.2
3.5 33.9 34.4 34.9 35.1 35.6
4.0 35.1 35.5 35.9 36.2 36.8
4.5 36.2 36.7 37.0 37.4 37.9
From former Table can be easily selected the required antenna. For the system frequency used and required gain,
the mesh parabolic reflector required is of 2.4 m diameter, installed at both ends, transmitter and receiver.
Once these calculations are finished, we can analyze the remaining factors of interest in System's calculations,
such as:
a) Path Attenuation for 0.1 % of Operating time:
The expression is as follows: A0.1 = 45 log d + 30 log f +78 [dB]
In our example, replacing numerical values:
A0.1 = 249.4 dB
This will be the value of Free Space Attenuation in Fading condition, predicted for 1x1000 of total operating time.
b) CCIR Margin for 0.1% of Total Operating Time:
The expression is as follows: M 0.1 = 35 log d - 10 log p + 10 log f - 78.5 [dB]
Where: p = Probability of Occurrence of Fading, generally taken about 0.01, in a general form p« 0.2 .
In our illustrative example: M0.1 = 30.6 dB
This is practically the limit of this parameter. It never will be lower than 30 dB.
Page 10
c) Percent of time in which this margin will be exceeded:
Expression for this Calculation is the following: % T = 0.1 (d)/2500 [%]

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
17
Where : d = Path length in Km.
In our Example: % T = 0.1 (40) / 2500
or : % T = 0.0016 %
This is a practically negligible time of fading ocurrence, since this type of link is designed for a 24-hour daily
operation, or 8760 hours per year. Assuming this time as 100%, the 0.0016% will be 8760 x 0.0016 / 100 = 0.14
hours in a year, or 8.4 minutes of expected fade time.
d) Noise Considerations. Reference Noise and System Signal-to Noise Ratio:
Reference noise is defined as "the total receiver noise level in absence of signal" and it's obtained adding all
random noise components involved in the appearing of noise at receiver's output terminals.
There are some components in the total noise at receiver's output. The theory of each component can be easily
found in any Text Book and is not of the scope of this Introduction. It's enough to know that, for a standard video &
audio microwave link as shown in our illustrative example, the noise components, and its numerical values, are the
following:
a) Noise Figure .............................................................................................. 5.0 dB
b) Boltzmann's Noise (kTo) ....................................................................... -204.0 dBW
c) 10 log BW = 60 + 10 log (4.2) .................................................................. 66.23 dB.
d) Modulation Gain ...................................................................................... - 7.09 dB
e) Weighting + Pre-emphasis/de-emphasis ............................................... -13.80 dB
_________________________________________________________________________
Reference Noise (No) -153.66 dBW.
That is : -123.66 dBm.
Received signal, as seen before, is at a -40 dBm level in order to keep the minimum Fade Margin of 40 dB. Taking
into account the above calculated Reference Noise, we can find now the Signal-to noise Ratio:
S / N [dB] = - (No- Srec.) = - ( -123.66 - ( -40) ) = 83.66 dBm.
If a deep 40 dB fading condition appears, and signal drops to threshold level, Signal-to-Noise Ratio will be kept in
the following value:
S / N thr [dB] = - ( -123.66 - (-80) ) = 43.66 dB
e) Link's Propagation Reliability:
For a certain analogic Radio Link, Propagation Reliability is given by the expression:
%R = 100 ( 1 - 10 -FM/10 )

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAYSYSTEM
18
Where: FM = Fade Margin in dB
Replacing with numerical values for our illustrative example:
%R = 100 ( 1 - 10 -4 ) = 99.99%
In other words, our formerly solved example represents a 2 GHz Radio Link whose Propagation Reliability
(independent from equipment's reliability) is 99.99%. These calculations can be performed within any frequency
band used, in any analogic Radio Link analyzed. Obviously, for Digital Radio Links these calculations are not
completely valid, since there are other additional factors involved in system's performance.
-----------------------o0o---------------------------

MT-MR PLATINUM. POINT TO POINT AURAL RADIORELAY SYSTEM
19
MT-MR PLATINUM
POINT TO POINT AURAL RADIO RELAY SYSTEM
chapter II
GENERAL SYSTEM DESCRIPTION
2.1.- Introduction.
MT-MR Platinum Radio Link System is a typical STL (Studio-Transmitter Link) used to carry aural information from
Production Studios to a distant Transmitter station. It is developed for practically all frequency bands below 1 GHz
that are generally used for this type of service. Both transmitter and receiver are fitted with high-stability PLL-
controlled oscillators, with TCXO reference frequency source, to accomplish the most severe frequency-stability
Rules and Regulations around the World.
MT-MR Platinum system is capable of carry a high-quality stereophonic program and three specialized SCA
channels used for commercial audio, low-frequency data transmission or telemetry/telecontrol purposes. This Radio
Link not only can work as STL point-to-point system, but it can also work as multiple-repeater Relay system in any
configuration, allowing to link very distant Transmission sites with its Production Studios. Facility of audio dropout at
each repeater station allows the creation of province or national chains having multiple Transmitter Stations.
Fig #..LT/LRDIG LINKUSEDFORSIMPLESTLAUDIO TRANSMISSION
As we said before, this Aural Radio Link can be built, at Customer request, in practically any frequency band
designed for these linking purposes. Originally designed for 400 MHz frequency band, further development of new
circuits will expand its range to 300-370 MHz, 470 MHz and even 900-960 MHz well-known frequency bands.