Satellite DXCC using Es'hail 2 satellite (my interpretation as at 2 October 2015)

 

Executive level summary of proposal

 

  • The satellite will be in geostationary position over 26 deg E and run commercially by the Qatar telecommunications authority for use in early 2017.
  • Amateur radio operators are granted two transponders on the satellite suitable for narrow or wideband use.
  • Small parabolic antennas around 0.6 to 0.8m suffice for the 2.4 GHz uplink and the 10.5 GHz downlink.
  • The satellite uses global beams covering that surface of the earth with a view of the satellite so satellite tracking will not be necessary.
  • The amateur X-band downlink will use one or more of the satellite's Ku-band TWTs at a power level of 32.4 dBW on bore sight, after a 6 dB power back off.
  • On the 2.4 GHz uplink a small PA of 5-10W is adequate for the narrow band transponder.
  • Considerably more uplink EIRP is required for digital TV working in the wide band transponder.
  • Linear transponder
2400.050-2400.300   MHz Uplink (centre 2400.175 MHz)
10489.550-10489.800 MHz Downlink ( centre 10489.675 MHz)

Wideband digital transponder
2401.500-2409.500   MHz Uplink (centre 2405.500 MHz)
10491.000-10499.000 MHz Downlink (centre 10495 MHz)
     

 

 

 

From: http://amsat-uk.org/2014/03/22/geo-transponders-on-eshail-2/

 

Es�HailSat-2 will provide a 250 kHz linear transponder intended for conventional analogue operations in addition to another transponder which will have an 8 MHz bandwidth. The latter transponder is intended for experimental digital modulation schemes and DVB amateur television.

Precise uplink and downlink frequencies remain to be finalized but the uplinks will be in the 2.400-2.450 GHz and the downlinks in the 10.450-10.500 GHz amateur satellite service allocations.

 

Both transponders will have broad beam antennas to provide full coverage over about 1/3rd of the earth�s surface. Precise operational plans will be finalised over the coming months and simple ground equipment will be required to use this satellite.

The spacecraft is expected to be ready for launch by the end of 2016.

 

More information  and reference document:

http://www.itu.int/en/ITU-R/space/workshops/2015-prague-small-sat/Presentations/Eshail-2.pdf

 

High Level Requirements

� Guidelines

� One-way communication channel requires 2.7 KHz (AM SSB Modulation) � 100 users = 50 communication channels. 250 KHz wide transponders can accommodate up to 100 communication channels.

� The mission is more interesting if the Earth areas at the edge of the satellite visible Earth are covered to allow users from Brazil to communicate with the Far East. Therefore, restricted antenna coverage to increase the spacecraft gain is not recommended.

� Frequency band selection

� Es�hailSat takes S/X-band solution for the AMSAT payload (a possible L-band/X-band operation was discarded for technical reasons)

� AMSAT is using RHCP in S-band. Es�hail-2 shall keep this convention.

� The S-band frequencies for the S/X payload will be at the lower spectrum edge and therefore far from the WIFI interference.

 

Space Segment: on-board design

� Using horn antennas for up- and downlink

� G/T at the Edge of Coverage (EoC): -12 dB/�K

� EIRP at the Edge of Coverage (EoC): 31 dBW (at 6 dB OPBO) � NPR is about 26dB for 6 dB OBO using COTS Ku-band TWTA.

� NB Transponder has an AGC function with an AGC Attack Time of 50 msec and an AGC Decay Time of 2 seconds.

 

 

 

 

 

 

View from Es'hail 2 at 26 E (InstantTrack)

White circle : 0 degree elevation contour

Red circle: approximate 10 degree elevation contour

 

Another view of the 5- and 10 degree elevation contours

http://www.amsat-dl.org/index.php/news-mainmenu-97/237-es-hail-2-satellite-amsat-payload

 

DXCC on Es'hail 2?

Inspection of the beams above reveals large areas with many DXCC entities within sight of the satellite.

Usually local obstructions prevent accessing a satellite at low elevation angles, typically below 10 degrees. Additionally, at elevations below about 5 degrees, and depending on antenna beam width, ambient geothermal noise becomes a limiting factor.

With this in mind, the list below was compiled. It indicates that at an elevation angle of 10 degrees or more, possibly 185 countries, minimum, are available. Around 111 or so could reasonably be expected to use the satellite in the fullness of time, but working more than the 30-40 obvious countries will take some time, maybe years. The design life of such a satellite is more than 10 years, probably up to 15 years.

 

So obtaining satellite DXCC using only Es'hail 2 is a strong possibility, particularly as commercial equipment becomes available to amateurs.

 

List of DXCC entities with a good view of the satellite elevation 10 degrees or so

 

Call

Entity

1A0

SMO Malta

3A2

Monaco *

3B6

Agalega/St Brandon

3B8

Mauritius *

3B9

Rodriquez

3C

Equatorial Guinea

3DA

Swaziland *

3V

Tunisia

3X

Guinea

3Y

Bouvet Is

4J

Azerbaijan *

4L

Georgia *

4O

Montenegro *

4S

Sri Lanka *

4X

Israel *

5A

Libya

5B4

Cyprus *

5H

Tanzania

5N

Nigeria *

5R

Madagascar *

5U

Niger

5T

Mauritania

5V

Togo

5X

Uganda

5Z

Kenya *

6W

Senegal

7O

Yemen

7P

Lesotho *

7Q

Malawi *

7X

Algeria

8Q

Maldives

9A

Croatia *

9H

Malta *

9G

Ghana

9J

Zambia

9K

Kuwait *

9L

Sierra Leone

9M2

Malaysia west

9N

Nepal

9Q

Zaire

9U

Burundi

9X

Rwanda

A2

Botswana *

A2

Oman *

A5

Bhutan

A6

United Arab Emirates *

A7

Qatar *

A9

Bahrain *

AP

Pakistan *

BY

China *

 

Antarctica ext N only

C3

Andorra

C5

The Gambia

C9

Mozambique

CN

Morocco *

CT1

Portugal *

CT3

Madeira Is *

CU

Azores *

D2

Angola

D4

Cape Verde

D6

Comoros

DL

Germany *

E3

Eritrea

EA

Spain *

EA6

Balearic Is *

EA8

Canary Is *

EA9

Ceuta and Melilla *

EI

Ireland *

EK

Armenia *

EL

Liberia

EP

Iran

ER

Moldova *

ES

Estonia *

ET

Ethiopia

EV

Belarus

EX

Kyrgyzstan *

EZ

Turkmenistan *

F

France *

FH

Mayotte

FR

Reunion Is *

FR/G

Glorioso

FR/J

Juan de Nova/Europa

FR/T

Tromelin

FT8W

Crozet Is

FT8Z

Amsterdam/St Paul

G

England *

GD

Isle of Man *

GI

Northern Ireland *

GJ

 Jersey *

GM

Scotland *

GU

Guernsey *

GW

Wales *

HA

Hungary *

HB

Switzerland *

HB0

Liechtenstein *

HL

Rep of Korea *

HS

Thailand *

HV

Vatican *

HZ

Saudi Arabia *

I

Italy *

IS

Sardinia *

J2

Djibouti *

J5

Guinea-Bissau

JT

Mongolia ext W only *

JW

Svalbard

JX

Jan Mayen

JY

Jordan *

LA

Norway *

LX

Luxembourg *

LY

Lithuania *

LZ

Bulgaria *

OD

Lebanon *

OE

Austria *

OH

Finland *

OH0

Aland

OJ0

Market Reef

OK

Czech Republic *

OM

Slovakia *

ON

Belgium *

OX

Greenland *

OY

Faroe Is *

OZ

Denmark *

PA

Netherlands *

S2

Bangladesh

PY

Brazil *

PY0F

Fernando/de Noronha

PY0P

St Peter/St Paul Rocks

R1/FJ

Franz Josef Land

S0

Western Sahara

S2

Bangladesh

S5

Slovenia *

S7

Seychelles *

S9

Sao Tomo and Principe

SM

Sweden *

SP

Poland *

ST

Sudan

ST0

Southern Sudan

SU

Egypt *

SV

Greece *

SV/A

Mt Athos *

SV5

Dodecanese *

SV9

Crete *

T5

Somalia

T7

San Marino *

T9

Bosnia Hercegovina *

TA

Turkey *

TF

Iceland *

TJ

Cameroon *

TK

Corsica *

TL

Central African Republic

TN

Congo

TR

Gabon *

TT

Chad

TU

Ivory Coast

TY

Benin

TZ

Mali

UA1

Russia *

UA2

Russia Kaliningrad

UK

Uzbekistan *

UN

Kazakhstan *

UR

Ukraine *

V5

Namibia *

VK0

Heard Is

VU

India *

VU4

Andaman & Nicobar

VU7

Laccadive

XT

Burkina Faso

XZ

Myanmar

YA

Afghanistan *

YB

Indonesia ext W only *

YI

Iraq *

YK

Syria

YL

Latvia *

YO

Romania *

YU

Serbia *

Z2

Zimbabwe *

Z3

Macedonia *

ZA

Albania *

ZB2

Gibraltar *

ZC4

Cyprus UK base *

ZD7

St Helena Is *

ZD8

Ascension Is *

ZD9

Tristan da Cunha/Gough

ZS

South Africa *

ZS8

St Edward/Marion Is

About 185 DXCC entities above 8-10 deg elevation

*  Likely to be initially active on this satellite (111 entities)

 

Link Performance Estimation from Design Requirements

The requirement specified simple antennas and low power PAs on the uplink. As can be seen, a couple of Watts into a 60cm dish in ZS-land is sufficient to access the narrow band transponder and obtain a reasonable S/N ratio for SSB use.

On the downlink, the satellite runs high power of 100W into a global coverage (probably simple horn) antenna with low gain of about 17 dBi, enough to effectively illuminate the earth below the satellite with an EIRP of 12.5 dBW per channel on bore sight, assuming 50 users are active simultaneously, and a 6 dB power back off on the TWT. A not very expensive X-band down converter with a noise temperature of 80K would be fine.

 

 

Overall link performance in SSB use, power sharing 50 active users

(http://www.satsig.net/linkbugt.htm)

 

 

Requirements in digital TV use from bore sight assuming a bandwidth of 3 MHz for a C/N of over 9 dB

 

Assorted Comments (mine)

�        A filter on the satellite uplink will be used to prevent amateurs running excessive power from overloading the RX. According to the description the S-band RX is "channelised" using digital signal processing, each "channel" having a SSB bandwidth. Apparently, the control station will transmit co-channel blocking power on the particular frequency in use if excessive signal level is detected. The remaining SSB channels operate normally.

�        To illuminate a parabolic antenna for the required RHCP on the 2.4 GHz uplink the feed must generate LHCP. However, linear polarisation will still work, but there will be a loss of 3 dB which will degrade the system S/N by less than 1 dB. The X-band downlink will use linear vertical polarisation on the narrow band transponder and linear horizontal polarisation on the wide band (digital TV) transponder.

�        As little as 2W on the 2.4 GHz uplink with a 65cm dish will provide a usable return signal

�        ZS-amateurs are particularly well placed being in the bore sight performance of both the up- and downlinks so can use smaller parabolics and less uplink power than in the design parameters listed above

�        Standard SSB bandwidth of 2.5 kHz will be used on the narrow band transponder, allowing a number of SSB compatible modes. Narrow band AM will work but FM will probably not fit in a channel.

�        Co-ordination will be required between amateurs when sharing the bandwidth of 8 MHz available on the wideband transponder to avoid mutual interference as 2-3 transmissions can be accommodated

�        To use digital TV in a bandwidth of 3 MHz (for example) 3m antennas and uplink power of 20 W will be required for a system C/N ratio of 9 dB which might be enough for quality demodulation if a detector with threshold extension demodulation is used in the X-band wideband RX

�        Fortunately high gain steer-able beams will not be used for amateur operation, otherwise they would simply be pointed at the busiest parts of the visible earth in the northern hemi, which would leave ZS-land out in the cold..

 

Equipment Required

�        It is necessary to have two rigs in order to monitor one's downlink signal, or else a dedicated satellite transceiver capable of simultaneous dual frequency TX/RX operation

�        Transmitting converter, probably 145 or 435 MHz to 2.4 GHz at 5-10 Watts for narrow band use. Uplink centre frequency 2400.175 MHz for narrow band transponder

�        Low noise receiving down converter, 10.489 GHz to 145 or 435 MHz. Downlink centre frequency 10489.675 MHz for narrow band transponder

�        Parabolic antenna of at least 60cm diameter in ZS-land

�        Dual frequency feed, or two separate feeds, for a parabolic with LHCP on 2.4 GHz and linear polarisation on 10.5 GHz

�        The elevation angle from ZS to the satellite is around 60 degrees, so the parabolic antenna can simply stand on a tripod or be mounted on a pole with a clear view of the satellite.