TECHNICAL DESCRIPTION AND OPERATING MANUAL ST131 <PIRANHA II> and ST131N
45
In case of automatic signal database creation method (“AUTOMATIC ANALYSIS”
submode) for calling signal list from memory press
then
and
.
For signal analysis select it from the database (on figure
database was created by manual method) and turn on demodulator
by pressing
. Select different types of demodulators by
pressing
and its selection form the list. Listen to the
sound. Use of headphones is preferred.
Use the fine-tuning option to get the well-tuned signal. To do this,
press
(the button will be highlighted in red). When
enabled, the tuning will be performed by rotating the rotary knob
with a step of 100 Hz.
When deciding to exclude signal from further analysis go out from “DEMODULATION” mode by
pressing
and then press
..
If signal is not being heard (for example, it is ceased to exist in broadcast) or more detailed
analysis is needed, go to the spectrogram indication. For that, go out form “DEMODULATION” mode by
pressing
and
.
If signal exist in broadcast, it will be shown at the center of the screen with 10MHz band.
Standard set of actions is possible here:
Increase/decrease of sight band – by
and
buttons.
Transition to signal oscillogram is done by pressing
and
. Transition to oscillogram
of demodulated signal – being in “DEMODULATION” mode – by pressing
button. Returning
to the spectrogram – subsequent press of
.
Is there is no operational possibility for signal source detection and necessity of more detailed
radio emitting analysis, use software “ST131Analyzer.Pro” options. Particularly functions, which are
absent when working only with a main unit ST131 – “Waterfall”, “vector analysis”, WAV file recording
for analysis by other manufacturers software.
4.1.4.1.4 Finding the source location
Detection is based on increasing the value of received signal
level on the screen ST131 approaching the source of the signal (so-
called amplitude method).To implement this method it is
necessary to replace the peak-hold detector used for
detecting radio signal. Choose what type of detector is determined
on the basis of Annex 1. Mainly, there is used the "PEAKx8" item
as a compromise option. But to search for signals with a constant
carrier frequency, the “AVERx8” option is better.
For correct detection of the location of their sources is desirable
to provide an indication of only one signal. This is achieved by positioning the cursor on the desired
signal and pressing
(when the BAND mode). Signal will automatically be in the center of the screen.
Next,
button selects the band for optimal display of this signal – one on a figure (mostly it is
1 to 10 MHz bands)
Next, by pressing
go to antenna movement in space with initial task of direction determination
of emitting source and subsequent moving towards the source.
Approach sign will be increasing value of signal level (on figure it is -48.2dB)
Using of “SCALE” submode is more convenient (see 3.6)