finding the accurate station's frequency using kSDRs

This page comes after a guru DXer asked me on how someone can read he accurate transmitting frequency from a given broadcasting. The story is very simple and here i just copy and paste my message to him, First watch carefully the picture. I have circled the major points to use in this simple maths

 

This is the case of RVM via the S Bernardo kSDR   i was centering  on 5940 . Which also circled in yellow

-153.8 Hz, is shown in the yellow circle . This is the transmitter’s offset frequency

In order this number to be seen get that you must and click on  SAM mode and then click on the audio tab.  The carrier shift that is noted in the second circle next to SAM text. 

 

Then the frequency yields

5940.0 kHz  - 0.1538kHz =5939,8462

Fro positive shifts, we have to add the number

5940.0 kHz  +  0.1964 = 5940.1964.

 

Important notice: Since the VCO may not always be perfectly aligned with GPS, it is advisable to check a few more stations, preferably European N American and Chinese which are correctly tuned, within the band in reference for potential tuning errors and perform the required calculations! The fastest way is to press [SHIFT] while tuning with the left click, which is aligned in the exact 5 kHz steps.

The margin of error could be approximately ±50 Hz. If the results are within the  ±5 Hz it is better these differences!

 

Comenting on the problem happened in the Sa'naa radio

 What I can understand from the waterfall and spectrum analysis with two pictures

This is clearly a carrier shifting upwards to around 8-9 kHz.  The modulation dissipates in proportion with the signal to a max length of 18 kHz reaching to around 11952KHz. Just see on how far it goes towards the right of the picture, The spectrum analyzer shows that the LSB part has less modulation than he USB part.

Today 25/9 around 10z the signal is centered on 11936.159 kHz. The supposed center is highly variable to a range of ±100Hz More zoom could help but as far as I tested it downgrades the clarity of the produced signal.

===================================

 

 

Here is the waveform with the chirping as tested in an audio program using the SAM mode : 10 HZ for the marked 1 second! There are two sub-chiprs that don't count which are shown with less amplitude than the other,