HellasSAT Hellas-Sat 2 User manual

User’s Manual
H
He el ll la as s- -S Sa at t 2 2 S Sa at te el ll li it te e
U
US SE ER R’ ’s s M MA AN NU UA AL L
September 2005
1

User’s Manual
INTRODUCTION
The HELLAS SAT User’sl Manual gives a short description of the Hellas- Sat 2 satellite system
and sets the procedures and calculations required for the user in order to access the satellite. It
is offered to the service providers and potential users of the system with the aim to provide all
necessary information for their systems planning and implementation of satellite services.
However, depending on the case, the information and guidance provided cannot be considered
as a specification but only as a reference tool.
DOCUMENT STRUCTURE
This document is divided into 3 sections. On section 1 all technical characteristics of the Hellas-
Sat 2 satellite are described. In section 2 the reader is introduced to the procedures and access
conditions of the satellite. Finally section 3 provides all necessary contact details for customer‘s
technically related issues.
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User’s Manual
1. SATELLITE TECHNICAL CHARACTERISTICS
1.1 INTRODUCTION
This Section contains general information on the multi-region geostationary Hellas-Sat 2
satellite.
1.2 GENERAL CHARACTERISTICS
The Hellas- Sat 2 satellite is designed for a minimum operational lifetime of 15 years and its
orbital position can be controlled with ±0.09º East/West and ± 0.05º North/South accuracy
over at least 12 years. In order to enable the pointing of manually adjusted or program-tracked
antennas, HELLAS SAT provides, on request, the data for orbit determination to the Earth
Station operators. Up to thirty (30) transponders of 36 MHz bandwidth each are available for
simultaneous operation, in eclipse as well as in sunlight.
Reception and transmission take place via four dual polarized beam antennas. Two of them
(F1 & F2) are fixed, with a 2.5m main reflector each and dual offset Gregorian configuration of
single feed with numerically shaped main reflector to provide complex beam shape for efficient
illumination of Europe, and part of Middle East and N. Africa. The other two antennas (S1&S2)
also Gregorian, are steerable with a shaped parabolic reflector of 1.3m to provide spot
coverage and can be pointed anywhere over the surface of the visible Earth, currently pointing
M. East (S2) and S. Africa (S1).
1.3 FREQUENCY PLAN
The frequencies and polarization arrangement of the Hellas-Sat 2 satellite transponders are
shown in Figure 1.
The fixed coverage antenna F1 receives signals in the band 13.75-14.00 GHz whilst the fixed
coverage antenna F2 receives signals in the band 14.00-14.25 GHz. The steerable antenna S1
receives signals in the band of 13.75-14.00 GHz.
The steerable antenna S2 receives signals in the band 14.00-14.25 GHz on the horizontal
uplink polarization and in band 14.00-14.50 GHz on the vertical uplink polarization. There are
two types of receivers/downconverters.
Type 1 receiver provides frequency translation of either uplink band 13.75-14.00 GHz or 14.00-
14.25 GHz to downlink band 12.50-12.75 GHz using two switchable local oscillators
(1.244GHz and 1.5GHz respectively). These receivers are connected in a 8/6 redundancy
scheme.
Type 2 receiver provides frequency translation of uplink band 14.00 to 14.25GHz, to downlink
band 10.95 to 11.20 GHz using a 3.050 GHz local oscillator.These receivers are connected in
a 2/1 redundancy scheme.
There are also two downconverter assemblies that provide frequency translation of the S2
uplink band 14.25-14.50 GHz to downlink band 11.45 to 11.70 GHz using a 2.8 GHz local
oscillator and connected in a 2/1 redundancy scheme.
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User’s Manual
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It is noted that, due to switching capabilities, channels 13-24(F1 antenna) or channels 37-48
(S2 antenna) may be downlinked in the band 12.50 to 12.75 GHz via the F1 antenna,
selectable on a channel by channel basis. It is also possible to downlink S2 channels of the
14.25-14.50 GHz band via the F2 antenna in the 11.45-11.70 GHz band but in this case the F2
channels have to be downlinked via the S2 antenna in the 10.95-11.20 GHz band.
Moreover, there is the possibility to uplink in channels 14 of F1 and downlink in channels 32 of
S1 on a channel basis thus connecting Europe with areas outside F1 coverage.

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Figure 1. Hellas SAT frequency Plan

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1.4 COVERAGE MAPS
Hellas–Sat 2 satellite provides four antennas for reception. The fixed coverage F1 and F2
antennas differ only in the shaping of the main reflectors. In practice they provide almost the
same coverage over Europe, N.Africa and Middle East.
Annex C provides the receive coverage areas in terms of G/T contours for F1, F2, S1 and S2.
The steerable antennas S1 and S2 are currently pointed to cover S.Africa and M.East/Eastern
Europe region respectively. S1 and S2 are of identical design.
Hellas- Sat 2 provides four antennas for transmission. The fixed transmit coverage of F1 and
F2 as well as those of the S1 and S2 are presented in Annex C in terms of EIRP contours.
1.5 TRANSPONDER GAIN ADJUSTMENT
Each transponder can be adjusted in terms of its gain. The adjustment is performed by a
channel amplifier (Camp) which is located before the TWTA. The Hellas- Sat 2 payload has 38
channel amplifiers. The Camp is a variable gain preamplifier for each individual TWTA and its
prime function is to limit the effects of rain fade. The Camp can be operated in two modes
selectable by ground command; Fixed Gain Mode (FGM) and Automatic Level Control (ALC)
mode.
In FGM, the gain of the Camp is selectable by telecommand. In this mode of operation, the
Camp has 27 gain steps (step 0 to 26 ), with a step size of 1.5 ± 0.3 dB.
In ALC mode, the Camp output signal power is set by telecommand to the required level while
the input power may vary over a specified dynamic range. In this mode of operation the Camp
has 17 gain steps (0-16), with a step size of 1±0.25 dB
From the operational point of view, the above arrangement provides flexibility to the earth
station operators in cases where the uplink station is power-limited and/or where power
compensation is required to cater for unpredictable link fade (rain etc.).
1.5.1 Saturation Flux Density (SFD)
The input power flux density for saturation of each channel is calculated at peak satellite
antenna gain. The peak saturated flux density is used in relation with the antenna G/T contours
relative to peak antenna gain and the sensitivity (gain step) of the transponder. The sensitivity
of each transponder may be adjusted independently from the others.
The SFD for transponder saturation at peak satellite antenna gain (at the maximum satellite
G/T point) ranges from about – 75 to – 115dBW/m² depending on the transponder gain step,
the antenna each transponder is connected to, and the particular TWTA.
Operationally, three gain modes are used; Low (L), Medium (M) and High (H). However, there
is the possibility to use other gain steps depending on the earth station EIRP capability, the
receive earth station G/T, earth stations location, the desired quality etc.

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In Table 1 below, the SFD values are presented for the above mentioned gain settings and for
each particular satellite antenna.
The quoted figures, based on the less sensitive transponder at nominal configuration,
represent average values for all transponders. This means that a difference of 1 or 2 dB from
the specified values is expected. Moreover, the peak gain values correspond to the minimum
available values. However, the quoted figures can be used in link budget calculations for
planning purposes.
A simplified link budget example is presented in Annex A to show how IPFD for saturation is
employed in link budget calculations.
Gain
Step F1 antenna F2 antenna S1 antenna S2 antenna
Peak Gain
+8.37 dB/K Satellite Contour
0 dB/K
Peak Gain
+11.10
dB/K
Satellite
Contour
0 dB/K
Peak Gain
+5.94 dB/K Satellite Contour
0 dB/K
Peak Gain
+5.65
dB/K
Satellite
Contour
0 dB/K
5(L) -82.20 -73.83 -84.9 -73.80 -80.90 -74.96 -76.80 -71.15
9(M) -88.32 -79.95 -91.12 -80.02 -87.16 -81.22 -82.95 -77.3
13(H) -94.66 -86.29 -97.37 -86.27 -93.44 -87.50 -89.16 -83.51
Table 1: Average SFD values for transponder saturation versus sensitivity
Using values from Table 1 and the G/T maps it is easy to calculate the SFD on a specific
location. The required SFD calculation formula is shown below.
SFD calculation formula:
)//(
_
LPeakPeakL
PeakL
TGTGSFDSFD
CorrectionAspectSFDSFD
−+=
⇒+= (Equation 1)
An appropriate example for the calculation of the SFD and all necessary parameters for a link
budget can be seen in Annex C.
1.6 ΒEACONS
A Ku- band beacon generator on board of the satellite provides a signal to a dedicated global
horn antenna. The Ku-band beacon transmits a single right hand circular polarized
unmodulated frequency of 11.4515 GHz with a maximum EIRP of 12 dBW within the whole
visible area from the satellite. A 3 dB loss of power level is expected if linear polarization
reception system is used by the station. This beacon is a two for one redundant unit and is
used by the earth stations operators to track the Hellas-Sat 2 satellite.

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1.7 TWTA TRANSFER CHARACTERISTICS
All TWTA which are employed on Hellas- Sat 2 transponders provide a maximum output power
of 105W.
The OBO denotes the power level available at the output of the TWTA relative to that when the
transponder is saturated. The OBO is therefore very important for link budget calculations as it
provides the available power per carrier for one or more carriers in the down link.
Operation of the TWTA at saturation means that the maximum output power is obtained in the
down link which in turn directly affects the design of the terrestrial receive equipment.
When a number of carriers are simultaneously amplified at different frequencies by the power
amplifier of a satellite transponder or of a transmit E/S, non-linearities of the amplifiers cause
intermodulation, i.e produce unwanted signals, called intermodulation products.
The number of intermodulation products increases very quickly with the number of input
carriers (for example, for 3 carriers, there are 9 products and for 5 carriers there are 50).
However, in most cases only the third-order intermodulation products falling within the
frequency band of the wanted carriers are considered.
To reduce intermodulation products in multicarrier operation (FDMA mode) the TWTA needs to
be driven with a sufficient back-off: i.e an input back-off of about 9 dB corresponding to an
output back-off of about 4.1 dB. In the case of earth station HPAs, an output back-off is usually
required (3 to 8 dB). However the situation can be improved by the utilization of linearizers.
Above limitations do not apply in the case of a single carrier occupying the whole transponder
bandwidth and therefore the TWTA can be driven almost to saturation.
For a Hellas-Sat 2 TWTA, in different operational modes, the following total IBO/OBO values
may be employed:
No of Carriers
1 2 3 4 MultiCarrier
IBO 0 -5 -7.5 -7 -9
OBO 0 -2 -3.1 -3.9 -4.1
Trp 1-12,
Beams F2, S2
C/IM - 27.7 18.5 18 18
No of Carriers
1 2 3 4 MultiCarrier
IBO 0 -5 -8.5 -8 -10.5
OBO 0 -2 -3.5 -3.4 -4.9
Trp 13-24 & 25-48
Beams F1, S1, S2/F1
C/IM - 26.5 18 18 18
Table 2: IBO vs. OBO for multi-carrier operation

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2. LEASED TRANSPONDER UTILIZATION CONDITIONS
The lessee is free to set his own transmission parameters (type of carrier, bandwidth,
modulation, quality etc), provided that this does not lead to unacceptable levels of interference
of any kind into the same or on adjacent satellites.
HELLAS SAT does not allow Power Limited links unless agreed otherwise between the two
parties.
Before any carrier activation, HELLAS SAT will prepare a link budget analysis and the lessee
will be asked to agree upon the operational parameters for the particular applications.
Alternatively the lessee can submit to the planning department for approval its own
calculations. In either way the operational parameters shall be included in an approved
Transmission Plan. Any deviation from the approved transmission parameters requires special
coordination and agreement by HELLAS SAT.
Prior to accessing the Hellas-Sat 2 space segment capacity all transmit Earth Station operators
have to submit to HELLAS SAT Operations Department Earth Stations approvals (Eutelsat,
Intelsat, PanAmSat etc). In case there is no such document, The Earth Station operator should
co-ordinate XPOL, frequency & power stability tests with HELLAS SAT NOC in advance.
All transmit Earth Station operators should strictly follow the HELLAS SAT Line-Up procedures.
The appropriate document is provided in Annex A.
3. CONTACT HELLAS SAT
HELLAS SAT can be reached at:
Tel: [phone].
Fax:[phone]
http://www.hellas-sat.net
The HELLAS SAT Booking Office is manned on a 24 hour basis. For capacity reservations and
technical matters are contact the following number:
Tel: [phone]
Fax: [phone]
The HELLAS SAT NOC is manned on a 24 hour basis. For line-up procedures or emergency issues,
contact the following numbers:
Tel: [phone] (primary),
Tel: [phone] (secondary)

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ANNEX A
HELLAS SAT NETWORK OPERATIONS CONTROL
Satellite Access Procedures
Purpose :
This document defines the procedures all Earth Stations must follow in order to access Hellas
Sat 2 Space Segment.
Customer Access :
In order to transmit to Hellas Sat 2 satellite, an authorization procedure should firstly take
place. Customers should originally contact Hellas Sat planning department (planning@hellas-
sat.net). After getting authorized, the Network Operations Control can be reached by contacting
the Shift Engineer ([phone]).
Line-Up Procedure :
There is a 10 minute Line-Up time that precedes the start of the booked time. During the
access procedure the customer must be ready to go behind specific steps. Particularly, the
Shift Engineer will require the following step-by-step sequence to be precisely tagged along:
A) CHECK-IN :
1) Check the antenna registration.
2) Check the carrier ID.
3) Confirm the uplink frequency.
4) Confirm the uplink polarization.
5) Confirm the start and finish transmission time (in case of permanent carriers this is not
required).
B) C/W CARRIER TRANSMISSION :
6) Check that a clean and power reduced carrier is transmitted.
7) Check the correct downlink frequency.
8) Confirm good cross-polarization isolation.
C) MODULATED CARRIER TRANSMISSION :
9) Check that a modulated carrier has been rapidly transmitted.
10) Adjust and confirm the level (C/N, EIRP) of the modulated carrier.
D) CHECK-OUT:
11) Request customer’s engineer mobile number.
12) Ask for a “good night” call that indicates the end of the transmission.

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ANNEX B
LINK BUDGET EXAMPLE
Example: Link between Athens and London on beam F2 transponder 03, multicarrier operation.
Transponder is set on FGM 09.
Picture 2 shows a snapshot from Satmaster indicating the required fields needed from the satellite
operator.
G/T and EIRP can be extracted from the coverages provided in Annex C
G/T
Athens =6.6dB/K
EIRP
London =53dBW
SFD can be extracted using equation 1 as follows:
2
/54.86
54.8658.412.91
)6.618.11(12.91
)//(
_
mdBWSFD
SFD
SFD
TGTGSFDSFD
CorrectionAspectSFDSFD
Athens
Athens
Athens
athensPeakPeakAthens
PeakAthens
−=
⇒−=+−=
⇒−+−=
⇒−+=
⇒+=

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ANNEX C
COVERAGE MAPS
53.94
52
52
52
50
50
50
50
48
48
48
48
46
46
46
46
44
44
44
44
44
SATSOFT
F1 Vertical Transmit 12,647 MHz EIRP Pattern
-8.00 -7.00 -6.00 -5.00 -4.00 -3.00 -2.00 -1.00 0.00 1.00 2.00 3.00 4.00
Theta*cos(phi)in Degrees
2.00
4.00
6.00
8.00
10.00
Theta*sin(phi) in Degrees
8.37
8
6
6
6
4
4
4
2
2
2
0
0
0
SATSOFT
F1 Horizontal Receive 13,768 MHzG/TPattern
-8.00 -6.00 -4.00 -2.00 0.00 2.00 4.0
0
Theta*cos(phi)in Degrees
2.00
4.00
6.00
8.00
10.00
Theta*sin(phi) in Degrees

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54.30
52
52
52
52
50
50
50
50
48
48
48
48
SATSOFT
F2 Vertical Transmit 11,135 MHz EIRP Pattern
-8.00 -6.00 -4.00 -2.00 0.00 2.00 4.00
Theta*cos(phi)in Degrees
2.00
4.00
6.00
8.00
10.00
Theta*sin(phi)in Degrees
11.10
10
8
8
8
8
8
6
6
6
6
4
4
4
2
2
2
2
SATSOFT
F
2
H
or
i
zon
t
a
l
R
ece
i
ve
14
,
021
MH
z
G
/
T
P
a
tt
ern
-8.00 -6.00 -4.00 -2.00 0.00 2.00 4.00
Theta*cos(phi)in Degrees
2.00
4.00
6.00
8.00
10.00
Theta*sin(phi) in Degrees

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52.16
52
50
50
50
50
48
48
48
48
46
46
46
46
44
44
44
44
SATSOFT
S1 HorizontalTransmit 12,729 MHzEIRP Pattern
-8.00 -6.00 -4.00 -2.00 0.00 2.00 4.00
Theta*cos(phi)in Degrees
-9.00
-8.00
-7.00
-6.00
-5.00
-4.00
-3.00
-2.00
-1.00
0.00
Theta*sin(phi) in Degrees
5°
5°
1
0°
10° 10°
5.94
4
4
4
4
4
2
2
2
2
0
0
0
0
-2
-2
-2
-2
SATSOFT
S1 Vertical Receive 13,768 MHz G/T Pattern
-8.00 -6.00 -4.00 -2.00 0.00 2.00 4.00
Theta*cos(phi)in Degrees
-8.00
-6.00
-4.00
-2.00
0.00
Theta*sin(phi) in Degrees

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5.65
4
4
4
4
2
2
2
2
0
0
0
0
-2
-2
-2
-2
-2
-4
-4
-4
-4
-6
-6
-6
-6
-6
-8
-8
-8
-8
-8
-10
-10
-10
-10
-12
-12
-12
-12
-14
-14
-14
-14
SATSOFT
S2 Vertical Receive 14,476 MHz G/TPattern
-6.00 -4.00 -2.00 0.00 2.00 4.00 6.00
Theta*cos(phi)in Degrees
-1.00
0.00
1.00
2.00
3.00
4.00
5.00
6.00
7.00
8.00
Theta*sin(phi) in Degrees