HackRF transmits okay first time, stops on second time, and okay third time, and repeats (add even). Why?

[electrical-pro]

https://user-images.githubusercontent.com/31592485/172065502-c15ec659-4b09-4887-8843-92f0582e70f2.mp4

Weird issue with HackRF One (please watch the video and listen). When I press the start/stop button HackRF transmits on add times but not on even. On odd times everything is fine. On even times, there is a carrier, but no modulation and the carrier seems to be weaker. I rarely use Hack RF for transmitting so I don't know when this issue started, maybe it's related to the firmware update (release 2021.03.1), but I'm not sure.

here are the settings I used sdrangel-7.3.1

I also tested with old sdrangel-4.14.3 and it has the same issue.

I used sdrangel-4.14.3 a few years ago without any issues, so I assume it may be related to HackRF firmware update (release 2021.03.1) that I did a few months ago.

What is causing this issue?

[f4exb]

This is normal. HackRF has a residual carrier remaining at the last frequency it was set.

[electrical-pro]

@f4exb, Hello, thanks for your response. I still do not fully understand. Why there is no modulation? Maybe I explained the issue poorly or I don't understand something. I expect HackRF to transmit a modulated signal every time it goes into TX mode. But it only transmits a modulated signal on odd times but not on even times when it goes into TX mode.

Expected behaviour: start/stop button clicked - transmission with modulation is ON start/stop button clicked - transmission with modulation is OFF start/stop button clicked - transmission with modulation is ON start/stop button clicked - transmission with modulation is OFF start/stop button clicked - transmission with modulation is ON start/stop button clicked - transmission with modulation is OFF start/stop button clicked - transmission with modulation is ON start/stop button clicked - transmission with modulation is OFF

Observed behaviour: start/stop button clicked - transmission with modulation is ON start/stop button clicked - transmission with modulation is OFF start/stop button clicked - transmission WITHOUT modulation is ON (why?) start/stop button clicked - transmission WITHOUT modulation is OFF start/stop button clicked - transmission with modulation is ON start/stop button clicked - transmission with modulation is OFF start/stop button clicked - transmission WITHOUT modulation is ON start/stop button clicked - transmission WITHOUT modulation is OFF

[f4exb]

For me it works normally starting with modulation at each ON.

[electrical-pro]

@f4exb, may I ask if you using the latest HackRF firmware release 2021.03.1?

I tested on another computer and observe the same issue. So I assume it's somehow related to my HackRF, it doesn't look like a hardware issue, so I think the latest firmware causes this.

Can anyone confirm the issue on HackRF firmware release 2021.03.1?

[f4exb]

It is much older than that:

hackrf_info version: git-cc7f599                                                                                                                                                                                                            
libhackrf version: git-cc7f599 (0.5)                                                                                                                                                                                                        
Found HackRF                                                                                                                                                                                                                                
Index: 0                                                                                                                                                                                                                                    
Serial number: 0000000000000000088869dc3878a51b                                                                                                                                                                                             
Board ID Number: 2 (HackRF One)                                                                                                                                                                                                             
Firmware Version: 2017.02.1 (API:1.02)                                                                                                                                                                                                      
Part ID Number: 0xa000cb3c 0x006a4761   

[Radiomix2000]

may I ask if you using the latest HackRF firmware release 2021.03.1?

Did you update CPLD too?

[electrical-pro]

@Radiomix2000, I did it before, but last time I didn't do it. But I think I don't have to do this anymore.

[github-actions[bot]]

This issue is going to be closed due to inactivity

[electrical-pro]

Fixed the issue by updating to release 2022.09.1