# Orbital Elements and Transponder

Some radios support the prediction of satellite passes and also ease satellite operations by correcting doppler shifts of up- and downlink frequencies. To this end, this feature turns a cheap handheld radio in a fully fledged satellite station.

The satellite editor dialog allows to select which satellites will be tracked by the device. The dialog also allows to specify the up- and downlink frequencies for the chosen satellites.

Screen shot of the satellite editor dialog.

## The satellite editor dialog.

To add a new satellite, click the Add button at the bottom of the dialog. You will be presented with a selection dialog of all known satellites.

Screen shot of the satellite selection dialog.

## The satellite selection dialog.

The list of all known (amateur radio) satellites is huge. You may search for a name using the Ctrl-F shortcut.

Once all satellites are added you are interested in, you can edit the transponder frequencies. In qdmr, a satellite may have an FM transponder, an APRS transponder and a beacon. At least one of these features should be configured.

The uplink (from earth to satellite) or transmit frequency as well as the downlink (from satellite to search) or receive frequency can be entered directly or selected from a known set of frequencies. To change a frequency, simply double-clock the field in the table.

Detail screen shot of the satellite editor dialog, selecting a downlink frequency.

## The satellite editor dialog: Selecting a downlink frequency.

Some satellites also require a sub-tone (CTCSS). These tones can be selected from the dropdown menu for up- and downlink separately.

Once all satellites and their transponders are set up, you can write the configuration to the radio using Write satellites from the Device menu.