recording of signal strength???

[Andre' Kesteloot]

Rik Strobbe wrote:

> At 10:01 26/03/99 -0000, G3XDV wrote:
> >On a similar subject, it would be really useful to be able to plot
> >signal strength against time (say, 24 hours) using a computer - for
> >simplicity it would help to use the sound card so that the same
> >connection can be used as Spectrogram. It is =just= possible to
> >do this with Spectrogram, though the amplitude resolution is poor
> >and only ten minutes or so can be moniored. Does such software
> >exist? Yes, I know I can build an A-D converter and write software
> >etc, etc but if someone has already done the work so much the
> >better.
>
> PC sound cards are only suitable for AC, so direct reading of the s-meter
> signal is not possible. The audio tone from the speaker output could be
> used but  than you have to be sure that the AGC is off and even then I
> doubt that the dynamic range (and linearity) is good enough for 'serious'
> recording.
> An alternative would be to send the s-meter signal to a V/F convertor and
> then to the sound card, this would require only minimum hardware (1 IC)and
> could provide thigh dynamic range and good linearity.
> But we still need the suitable software, althuogh this shouldn't be too
> difficult to write if you know how to read the sound card.
>
> 73, Rik