What do the letters in a satellite’s mode designator specify? [E2A05]
A. Power limits for uplink and downlink transmissions
B. The location of the ground control station
C. The polarization of uplink and downlink signals
D. The uplink and downlink frequency ranges
Lets look at “mode designators” to understand what the question is about. A mode designator is simply a letter that indicates what band to use when sending to (uplink) or listening to (downlink) a satellite. For example, a U/U code means that both the uplink and downlink frequencies are in the 70cm band. A V/U code means that the uplink is in the 2m VHF band, while the downlink is in the 70cm UHF band.
The answer then is D. The uplink and downlink frequency ranges.
Here is a list of mode designators:
| Designator | Band | Frequency (General) |
| H | 15 m | 21 MHz |
| A | 10 m | 29 MHz |
| V | 2 m | 145 MHz |
| U | 70 cm | 435 MHz |
| L | 23 cm | 1.2 GHz |
| S | 13 cm | 2.4 GHz |
| S2 | 9 cm | 3.4 GHz |
| C | 5 cm | 5 GHz |
| X | 3 cm | 10 GHz |
| K | 1.2 cm | 24 GHz |
| R | 6 mm | 47 GHz |
Source: https://en.wikipedia.org/wiki/OSCAR#Mode_designators