[Fwd: LF: Slow CW]
Sun, 29 Nov 1998 08:45:20 -0500
M. Bruno wrote:
> At 09.22 29/11/98 +0100, you wrote:
> >from HB9ASB, JN36pt
> >Finally I'm also ready for the "CW Television mode". The QRS pgm from
> >ON7YD works perfect with Win98 (thank you Rik!), also the newest
> >spectrogram version (thanks Johan for the download link!).
> >Can somebody tell me about a good starting set up for the spectrogram?
> >Do we use now the RST or the TMO scheme for the reports?
> >73 de Toni
> Hello Toni and all,
> this is a message I posted about a month ago:
> I did some tests to found the best setting of Audiogram for weak signal
> I used a signal generator modulated by SLOWCW. The signal was radiated by a
> short wire
> and then received by the main aerial, to include the 'true' band noise.
> After several tests, I found the following:
> - The best setting of Audiogram is 5.5 kHz, 16 bit sampling; 16384 points FFT;
> 200 msec dwell time; 4 times spectrum average. This gives a nominal BW of
> 0.36 Hz.
> - The best dot interval is (as expected) 3 seconds. Even 2 seconds is
> useable if the S/N is
> a bit better. I found no significant improvements going to 10 sec dots and
> 16 times average.
> During the tests the S/(S+N) was roughly 6 dB, but since the noise is
> highly impulsive
> it is difficult to assert a true ratio.
> That setup for Audiogram seems to work well. I use the RX with 300 Hz of BW
> and the BFO set at about 700 Hz; then center the Audiogram analysis band
> that (660/746 Hz for instance). You may decide to vary the dwell time to
> your preference.
> I continue to suggest the "T-M-O" signal reporting for reasons of shortness
> and detectability
> in the noise.
> For all OMs willing to listen I will make another test transmission by next
> Tuesday from
> 1930z thru 2130z on 137.770 kHz. Any report will be welcome !
> Happy CWTelevisioning to all (Videography?)
> 73 - Marco
> Marco Bruno - IK1ODO
> SPIN Electronics - www.spin-it.com