The configuration process for VARA FM and VARA HF differ slightly due to the different modulation techniques used for each.

Configuring VarAC when using a standard mobile rig without CAT control:

Once your transceiver is plugged in to the USB ports, open the Windows Device Manager and determine the COM port numbers applicable for the CAT control, and if relevant, for the PTT. In some cases the PTT will be controlled via CAT commands or alternatively by toggling either the RTS or DTR serial port lines.

Jot down these COM port numbers as you will use this within the VarAC rig configuration.

Go to the Rig Tab on the VarAC Settings menu. For the Frequency Control settings, select NONE. You have the choice of either controlling the rig PTT with VarAC or with VARA FM. The choice is yours. If you control the PTT via VarAC set this up under the PTT Configuration options. Select DTR/RTS and then select the appropriate COM port in the bottom right of the config screen. Remember to select either DTR or RTS as the line to control the rig PTT.

Configuring VarAC when using a VHF rig with CAT control:

Determine how you will be managing the PTT on the rig. Using a digital rig interface between your PC and the rig will determine which COM port is allocated to control the PTT. In addition an additional or the same COM port may be used for CAT control. Use the Windows Device Manager to determine which COM port is allocated. Make a note of the COM ports as you will use that when configuring VarAC’s rig controls and VARA FM.

Irrespective of whether your rig uses CAT control (to change frequency and activate PTT) or not, configuration of VARA FM itself is the similar for both rig types.

Watch this short video of the process involved.

Here are some further pointers:

• Ensure that you never move your USB rig cable between different USB ports on your PC. When you move your USB cable to a different USB port Windows will reallocate COM port numbers to these devices and you will have to reconfigure your rig control in the various configurations again! To keep the COM port allocation consistent, plan on which USB port you will use and consistently plug the same cables/device into the same USB port.

• I have set up shortcuts on the Windows desktop to speed up the process of gaining immediate access to the Sound Control Manager and the Device Manager

  
  
  
  
  

  Paste the following text into each of the Target fields to set up each shortcut:

  • Windows Sound Manager: C:\Windows\System32\control.exe mmsys.cpl sounds

  • Windows Device Manager: C:\Windows\System32\devmgmt.msc

• It is vital to set appropriate volume levels between the rig and the PC. Any form of distortion will have a marked negative impact on the quality of the modulation and consequent data throughput.

• Since it is difficult to determine the correct volume level output from the PC to the rig, rather set this volume level too low.

By ZS2OK