zoom frequency range

[Jeremy Rutman]

Hi, 
I'm interested in using gqrx to study motor noise. For this purpose I got an HF airspy + and see a spike from the motor of interest at ~15kHz. 
1. I would like to zoom in on this area but the mouse wheel and various kbd shortcuts seem not to allow for such - is there a way to do it? 

2. Can I get a FFT or other spectrum from gqrx 

3. What is the meaning of the negative frequency region , below 0 Hz? 

4. Would a low-noise soundcard be more suitable for measurement of these low frequencies (DC-20Khz) ? 

Thanks 
Dr. Jeremy Rutman

[Jeremy Rutman]

apologies about the FFT question, of course I have a spectrum in the lower window - is there a way to change integration time for this? 

[Jeremy Rutman]

and further apologies about the zoom , scroll wheel while on the freq. axis takes care of it. That leaves:

3. What is the meaning of the negative frequency region , below 0 Hz? 

4. Would a low-noise soundcard be more suitable for measurement of these low frequencies (DC-20Khz) ? 

5. Is there a way to change integration time to pick up faint signals