[Lf] [Fwd: LF: qrss]

[Andre' Kesteloot]

Rik Strobbe wrote:

> Hello Malcolm,
>
> >Can anyone explain to me why qrss is necessary on 136 khz. All the
> >activity that I have heard on this frequency is workable on normal speed
> >cw at my qth.
> With Gram (if used properly) you can easily 'see' signals that are 15 to
> 20dB below the audible level. It is a physical law that SNR is inverse
> proportional to bandwidth. Practical bandwidth for 'copy by ear' is 30 to
> 50Hz, with QRSS you can achieve a bandwidth below 1Hz.
> Last sunday I had a QRSS/DFCW QSO with G0MRF, his signal was completey
> inaudible.