[Discuss-gnuradio] QT_GUI_frequency_ sink is not setting a frequency variable on click

[Manfred Weiss]

Hi all,

I have the following problem with the QT GUI frequency sink and QT GUI 
waterfall sink (test was done with version 3.7.10):

I want to set a variable (freq) when I click into a QT waterfall sink or a QT 
frequency sink. The value of this variable (freq) should then be used to set 
the frequency of a signal source or a uhd_source AND at the same time it should 
update the value of a QT_GUI_RANGE counter display. With the old WX GUI 
elements this works perfect, see attached example wx_fft_click.grc. There you 
click into the waterfall or the fft spectrum display and the frequency is 
changed as well as the slider position or the displayed frequency.

But when I try the same with the example qt_fft_click.grc it is working only 
partly. First you have to make a double click that it changes the frequency but 
now the problem is that the GUI Range slider is not changed and also the 
frequency in the slider value box is not updated.
And this is a big problem if you want to control the receiving frequency of a 
SSB ham radio receiver / transmitter by clicking into the waterfall display. If 
you do this a few times you do not know at which frequency you actually have 
tuned the transceiver because it is not updating the frequency variable. And 
additionally if you need a fine tuning of the receiving frequency because the 
click was not accurate enough you need also the value of the frequency variable 
that is currently not updated in the QT GUI elements.



Best wishes
Manfred

qt_fft_click.grc
Description: application/gnuradio-grc

wx_fft_click.grc
Description: application/gnuradio-grc