VARA configuration for "Hardware" Push-To-Talk.

Custom Products for the Digital Radio Amateur Enthusiast

Hardware Push To Talk settings for VARA FM and HF

By Kevin Custer W3KKC

C-Media Hardware PTT is a logic level change in the radio interface that results in a push-to-talk signal that is used to key the radio. All DRA's have Hardware PTT capability, as we use C-Media chipsets in all of our radio interfaces.

Many other radio interfaces derive the PTT by detecting the presence of audio from the application. That audio is detected by a VOX circuit that generates the logic that actuates a relay to make the radio transmit.

DRA's don't work that way when using VARA. Here's how to implement the setting in the software.

Make sure you're using the latest versions of the VARA software. Update if necessary.

Use the menu system (in VARA) to enable the C-Media "Hardware PTT". In VARA, this is called RA Board and in this case RA also means DRA.

For VARA FM:
Under Settings > SoundCard:
1 - choose the DRA (by selecting the USB PnP Sound Device) in both the input and output sections. Choose RA-Board -1 in the PTT box. If you have more than one DRA connected to your computer - identify them and set the RA Board (number) accordingly.
2 - Choose the L+R radio button under "Channel".

Under Settings > PTT, choose the RA Board radio button selection.

Close the program - reopen it, and try a test transmission. When Hardware PTT is operating correctly the RED LED illuminates when you'd expect the PTT to be asserted - like when the "TUNE" button is depressed.

For VARA HF:
Under Settings > VARA Setup, choose RA Board PTT at the bottom check-box.

Under Settings > SoundCard:
1 - choose the DRA (by selecting the USB PnP Sound Device) in both the input and output sections. Choose RA-Board -1 in the PTT box. If you have more than one DRA connected to your computer - identify them and set the RA Board (number) accordingly.
2 - Choose the L+R radio button under "Channel".

Email Kevin Custer for additional support.