General description
The SkyBoost mode has been developed according the specifications of our most demanding professional customers. It’s perhaps the most modern operating mode for the very long distance communications in HF (error free communication even 16 db below noise level). The SkyBoost is based on the multitone FSK modulation and the used bandwidth is 344 Hz. It also utilises the most modern FEC (Forward Error Correction) techniques as well as interleaving. The SkyBoost provides 21.9 WPM text throughput with FEC and 43.8 WPM with no FEC. SkyBoost uses soft bit Viterbi decoding in FEC mode.
The decoder searches the SkyBoost transmission in the range of the given frequency boundaries. Also you can set the first SkyBoost frequency by doubleclicking mouse on the wanted frequency position. The numeral value of the first SkyBoost frequency is shown on the screen. When SkyBoost transmission has been detected in the given range, the decoder will then lock itself to that frequency. When locked, the decoder draws the bolded blue line on the spectrum display on the currently locked frequency (blue line is drawn on the 1st tone frequency. If the decoder is not locked, then the blue line is not shown as bolded. When the frequency is locked, the decoder starts to estimate the keying parameters of the transmission. When all the parameters have been estimated then the decoder starts to print characters on the screen. In the locked state, the carrier frequencies are automatically monitored in the given frequency boundaries and if the carrier frequency changes, then the decoder moves to a new frequency. If 'Lock' is pressed in the user interface, then decoder will not automatically change it's frequency. ‘Reset’ resets the decoder and received text can be saved using ‘Save’. The parameters can be modified by pressing the ‘Config’ button. Note, that you can install several decoders in one configuration if needed.
Configuration
Pressing the ‘Config’ button opens the following configuration dialog.
Parameters:
Tone scan area
The scanned frequency range is given with two values low and high. The SkyBoost transmission searched only inside this frequency window.
FEC
If FEC is selected the Forward Error Correction is in use. This means that interleaving and convolution coding is used to protect the data. When FEC is selected the text throughput will be dropped by 50%.
FFT
The FFT button opens and closes the power spectrum window. You can for example close the power spectrum window when the decoder has locked into correct frequency in order to get more space for text window
Save
The save button opens the log file control dialog, which is used to open or close a log file. The detector text window can be also saved into file or sent into socket.
Lock
The lock button locks or unlocks the decoder frequency. Decoders have the automatic frequency scanning feature. Push the lock button when you want to lock decoder into selected frequency. Push Un-Lock button when you want to release the frequency locking.
Reset
The reset button resets the decoder and clears the text window.
