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# HackRF TXCO Install
- URL: https://www.fieldnotes.wtf/hackrf-txco-install/
- Published: 2022-11-27T21:00:00.000Z
- Updated: 2026-07-01T20:58:48.000Z
- Author: Zach Rogers
- Tags: notes

Quick reference for installing the TCXO on a HackRF One.

# Pinout

![TCXO installs on the P22 connector, on pin 1](https://storage.ghost.io/c/f0/ee/f0eeb44c-5427-43ea-a9d4-b41ee344c735/content/images/2026/07/hackrf1_tcxo_pinout.jpg)

The TCXO module gets installed on the 12-pin P22 connector on the HackRF One. You will want to install the module on pin 1, which is closest to CLK IN / OUT on most boards.

# Testing

To test, you will want to run the following command, which can be built from the [HackRF source](https://github.com/greatscottgadgets/hackrf?ref=fieldnotes.wtf):

```
hackrf_debug -–si5351c -n 0 -r

```

If all is working, you should get the following output:

```
[  0] -> 0x01

```

If your output does not match this, that means that the TCXO is not being used. The HackRF One firmware may need to be updated.

Happy hacking!

`<3 Zach`