[email protected] wrote:

>My half-penny's worth is that the transmitted energy per symbol is 3.3
>times larger, giving exactly 5.23 dB improvement ;-) That's assuming
>that the FFT bandwidth is somewhere near the optimum (0.3 Hz and 0.1
>Hz respectively).

Markus,

you are correct, but in an ideal situation. Given that for performance
reasons the FFT works at its best when done
on a sample length which is a power of two, in Argo, when going from
QRSS3 to QRSS10 I multiply the sample length
by four, which causes a reduction of four times of the bin size. This
has the consequence that the noise energy that falls
into a single bin is 6 dB lower, hence the 6 dB gain in SNR.
There are algorithms to perform FFTs on arbitrary sizes, but they are
slower than when working with powers of two.

73  Alberto  I2PHD