Dual Channel Spectroscopy
=========================

.. figure:: /images/dual_chan_spec_stack/stack_front_angle.jpg
   :width: 100%
   :align: center

   Dual Channel Spectroscopy Stackup

This stackup consists of the following hardware modules:

- Kāhu Spectrometer
- Gradient Amplifier
- Shim Amplifier
- Two 50 W RF Amplifiers

Hardware Setup
--------------

This section will guide you through the setup process for the Dual Channel Spectroscopy configuration.

Step 1 - Amplifier tuning
^^^^^^^^^^^^^^^^^^^^^^^^^
First confirm that both the RF amplifiers are tuned to their target frequency by fitting the correct quarter-wave line module in each.
To learn how to change the quarter-wave line module, see the :ref:`hardware/rf_amplifier:How to retune the 50W RF Amplifier` section.

Step 2 - Stacking
^^^^^^^^^^^^^^^^^^
Begin by stacking the modules as shown below, with the two RF amplifier modules at the base of the stack, followed by the Shim and Gradient Amplifiers and with Kāhu on the top.
When viewed from the back, the gradient amplifier is on the left and the shim amplifier on the right.

.. figure:: /images/dual_chan_spec_stack/stack_back.jpg
   :width: 100%
   :align: center

   Rear view of Dual Channel Spectroscopy Stackup

Step 3 - Cable connections
^^^^^^^^^^^^^^^^^^^^^^^^^^
.. warning::
    **Ensure amplifier modules are powered OFF during Kāhu power up and shutdown, or while changing RF connections.**

Complete the rear, then front cable connections for each module following the setup guides listed below.

- Step 2 - 3 in the 50 W RF Amplifier :ref:`hardware/rf_amplifier:Setup Guide`
- Step 1 - 2 in the Shim Amplifier :ref:`hardware/shim_amplifier:Setup Guide`
- Step 1 - 2 in the Shim Amplifier :ref:`hardware/gradient_amplifier:Setup Guide`

.. caution::
    **Ensure each module is powered with the correct supply by taking note of the power rating**

Your stackup should now look the same as the images below.

.. figure:: /images/dual_chan_spec_stack/front_connections.jpg
   :width: 100%
   :align: center

   Stackup Front connections

.. figure:: /images/dual_chan_spec_stack/rear_connections.jpg
   :width: 100%
   :align: center

   Spectroscopy Stackup rear connections


Step 4 - Power up
^^^^^^^^^^^^^^^^^^
Finally you may power on Kāhu and establish a network connection from your PC. Once Kāhu power up has finished, you can power on the Amplifiers with the power switch on the front of each module.
The power light of each hardware module will illuminate when powered, and the blue light will flash on when the modules are active/amplifying as seen in the image below.


.. figure:: /images/dual_chan_spec_stack/modules_on_active.jpg
   :width: 100%
   :align: center

   All modules powered on and active