George, Andrej, LF,
I've run a splitted EU-60 grabber window now for some time, waiting
until a relatively weak signal appears to times of high QRN.
Attached is that splitted spectrogram of the grabber, showing "GB" in
QRSS-60 on 136.1698 kHz, by Andrej/EW6GB.
As visible, the spectrograms are taken in Spectrum Lab. The upper half
shows the LF signal without band limiting and noise blanking, as done in
many other programs. The lower half shows the same signal from the same
instance but taken from behind a 2.5 kHz wide band filter and a
noiseblanker.
Without the NB, GB is invisible or not readable. When using the NB, GB
is clearly visible! The effect is impressive when QRN crashes are
strong, nearby thunderstorms and that stuff. In the typical daylight LF
background noise the effect is less expressed.
Yes yes, all this is not new but we have some newcomers on LF and so it
may be useful to demonstrate the effect of the SpecLab noiseblanker.
73, GL, Stefan/DK7FC
SL NB @ QRN.jpg
Description: JPEG image
|
