Verifying external clockinput and 1pps on HackRF SDR

[swapnachallagundla]

Have you read the HackRF troubleshooting documentation?

yes

What outcome were you hoping for?

How to test if the external 10MHz and 1pps inputs are activated or not on Hack Rf radio?

What outcome actually happened?

I want to synchronize multiple hackrfs installed at different places. I am using GPSDO for generating 10MHz clock input and 1 PPS for frequency and time synchronizations. I connected 10MHz at CLOCKIN input and 1pps at pin 16 of P28 on HackRF. Now I want to test whether these two signals are actually detected or not. I used the command "hackrf_clock -i" to check it. But I did not get anything.

I also tried to use this command "hackrf_debug -s -n 0 -r" in terminal during transmission/reception. But it displaying the message hack rf already in use.

What operating systems are you seeing the problem on?

Linux

What is the output of hackrf_info?

N/A

Are you using any third-party software?

N/A

Are you using any third-party hardware?

N/A

[mmm545]

I also tried to use this command "hackrf_debug -s -n 0 -r" in terminal during transmission/reception. But it displaying the message hack rf already in use.

Did you try running the command while NOT receiving/transmitting? Because that's what you're supposed to do.

[swapnachallagundla]

Yes, I tried. It returned 0x51 when I run the above command.

Do I need to run any commands after connecting these external inputs?

[swapnachallagundla]

When I run the command hackrf_debug --si5351c -n 0 -r on r6 model it displays 0x01

and when I run the same command on r8 and r9 models it displays 0x51.

Also, hackrf_clock -i is not working and it displays invalid option when I run this command.

[martinling]

You should use hackrf_clock -i to check for the presence of the external clock input. This needs to be run when the HackRF is not in use by other software. If a clock is detected on CLKIN, it will be used automatically when TX/RX is started.

The old way of checking this using hackrf_debug is deprecated, and does not work with all hardware revisions.

You can check that the 1PPS input is working by running hackrf_transfer with the -H option for hardware triggering:

hackrf_transfer -r /dev/null -H

This should display Waiting for trigger... and then start reception on the next 1PPS pulse.

[martinling]

Also, hackrf_clock -i is not working and it displays invalid option when I run this command.

Then you should update your host tools to a newer version, which will have this option.

[swapnachallagundla]

We are using the latest version r9 of hackrf which is updated firmware.

[martinling]

Yes, but if your hackrf_clock does not have the -i option then your host software is older than that. That option was added in #1135 and included in the 2022.09.1 release.

[swapnachallagundla]

Thanks. I have updated host software. Now, I am able to detect clock and 1pps is also working.

[martinling]

Great! Glad we could help.