P4-A NB Transponder Bandplan and Operating Guidelines

P4-A NB Transponder Bandplan and Operating Guidelines

Oktober 19, 2018 Aus Von Peter Gülzow

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 Bandplan

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 Bandwith [kHz] Notes
10489,550 – 10489,555 do not transmit Lower Beacon, 400 Bit/s BPSK or CW
2400,055 – 2400,100 10489,555 – 10489,600 45 CW Only
2400,100 – 2400,120 10489,600 – 10489,620 20 narrowband digimodes (500 Hz max. BW)
2400,120 – 2400,140 10489,620 – 10489,640 20 digimodes (2700 Hz max. BW)
2400,140 – 2400,190 10489,640 – 10489,690 50 mixed modes  (2700 Hz max. BW)
2400,190 – 2400,295 10489,690 – 10489,795 105 SSB only
10489,795 – 10489,800 do not transmit Upper 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 polarisation is RHCP (right-hand circular polarisation).
  • 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 (simiar to the P3-satellites) or in CW.
  • The beacons are generated in 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:

 

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