Qatar-OSCAR 100 (QO-100)

Qatar-OSCAR 100 (QO-100)

Qatar-OSCAR 100 (QO-100)

02.02.2019 On 15 November 2018 Es’hail-2/P4A was launched with a SpaceX Falcon 9 launcher from Cape Canaveral Air Force Station Space Launch Complex 40 in Florida. Es’hail-2/P4A was jointly developed by QARS (Qatar Amateur Radio Society) and Es’hailSat (The Qatar Satellite Company), under the technical leadership of AMSAT-DL, and is the first geostationary amateur radio payload. The satellite reached its final position at 25.9°E and the narrowband and broadband transponders were successfully tested on 23 December 2018 and 16-17 January 2019. The transponders are expected to open for general use in February 2019.

At the request of AMSAT Deutschland e.V., QARS and Es’hailSat, AMSAT hereby designates Es’hail-2/P4A as Qatar-OSCAR 100 (QO-100). May the 100th OSCAR satellite be the lead star for future amateur radio satellites and payloads in geostationary orbit and beyond.

P4-A NB Transponder Band Plan and Operating Guidelines

P4-A NB Transponder Band Plan and Operating Guidelines

This guide is being issued as an initial document in advance of the launch and commissioning of the Es’hail-2 spacecraft. This will enable potential users to be informed about the plans and operating procedures that should be adopted. It is expected that the document will be updated regularly to take into account the operational experience.

This chart shows the two transponders, their passbands and uplink and downlink polarisations. Note that, unlike the linear transponders on most other amateur satellites, these transponders are not inverting.

The two amateur band transponders on Es’hail-2 are a hosted payload being provided by the Qatar Satellite Company – Es’hailSat and the Qatar Amateur Radio Society (QARS) in co-operation with AMSAT-DL. It is vital that operators respect this facility and refrain from any activity that might cause offense, or which is outside the terms of their amateur radio licence.

Es’hail-2/P4-A Narrowband Transponder Operating Guidelines and Band Plan

The narrowband transponder is intended for conventional analogue and narrowband digital signals.

No transmissions should be made beyond the nominal edges of the transponder passbands. In particular, no operation should take place below the lower beacon nor above the upper beacon.

No uplinks should result in downlink signals that are stronger than these beacons. In the event that such signals are detected, they will be marked by a „LEILA“ siren. When they have been marked by „LEILA“, operators should immediately reduce their uplink power (ERP).

No FM transmissions should be made to Es’hail-2 as these would use excessive power and bandwidth.

Although there is no formal bandplan, the following details are provided for initial guidance.

Uplink [MHz]Downlink [MHz]available Bandwidth [kHz]notes
10489,550 – 10489,555do not transmitLower beacon, 400 bit/s BPSK or CW
2400,055 – 2400,10010489,555 – 10489,60045CW Only
2400,100 – 2400,12010489,600 – 10489,62020narrowband digimodes (500 Hz max. BW)
2400,120 – 2400,14010489,620 – 10489,64020digimodes (2700 Hz max. BW)
2400,140 – 2400,19010489,640 – 10489,69050mixed modes (2700 Hz max. BW)
2400,190 – 2400,29510489,690 – 10489,795105SSB only
10489,795 – 10489,800do not transmitUpper Beacon, 400 bit/s BPSK or CW
  • above Frequencies are preliminary and will be confirmed/updated after launch.
  • NO FM mode is allowed on the transponder.
  • No transmission below the lower beacon and no transmission above the upper beacon.
  • The NB transponder is a bent-pipe transponder and non-inverting.
  • Uplink polarization is RHCP (right-hand circular polarization).
  • Downlink polarisation for the NB transponder is V (vertical linear polarisation).
  • Monitor the beacons and keep your own signal level below, otherwise you might trigger LEILA warnings.
  • Please use minimum uplink power (ERP) .
  • Full-Duplex operation is mandatory (you must be able to monitor your own downlink while transmitting!)
  • The beacons are modulated in 400 bit/s BPSK (similar to the P3-satellites) or in CW.
  • The beacons are generated by the groundstation and will provide selected telemetry from the main satellite related to our amateur radio transponders. Details are still to be defined and will be published later.

coverage map

This map shows the coverage expected using the global beams on the spacecraft. For broadcast satellites it is usual to show the coverage down to 5 degrees elevation, but it is expected that well sited locations may provide access beyond that shown. The actual limits and power/dish sizes required will not be known until after commissioning.


Here is another map shopwing the maximum possible visibility area at 0° elevation angle: