Option 10 provides a bias tee that is installed inside the instrument. The bias arm is connected to a 12 VDC to 32 VDC power source that can be turned on as needed to place the voltage on the center conductor of the VNA Port 2 (in VNA mode; see Figure: Bias Tee Setup in VNA Mode) or the center conductor of RF In (in SPA mode; see Figure: Bias Tee Setup in SPA Mode). This supply of bias is useful when conducting two‑port transmission measurements and can also be used to provide power to block down‑converters in satellite receivers or to power some tower‑mounted amplifiers (TMAs).
Bias Tee in VNA Mode
The bias can be turned on only when the Start Frequency is 2 MHz or greater. When bias is turned on, the bias voltage and current are displayed in the Instrument Settings Summary area of the screen. The 12 VDC to 32 VDC power supply is designed to continuously deliver a maximum of 6 watts.
When in VNA mode, the bias tee menu can be accessed as follows:
• From the Sweep menu when in standard VNA mode:
Key Sequence: Sweep > Configure Ports > Bias Tee Setup
• From the System Options menu when VNA Field menus are selected:
Key Sequence: Shift, System (8) > Application Options > Bias Tee Setup
Bias Tee Menu
Bias Tee: Toggles On and Off the variable power supply.
Int Voltage P2: Use this submenu to set the power supply voltage.
Int Current Limit P2: Use this submenu to set the power supply current.
Back: Press this submenu key to return to the Configure Ports menu.
Figure: Bias Tee Setup in VNA Mode shows how the LMR Master provides an internal voltage between 12 volts and 32 volts that is applied to the center conductor of Port 2. That voltage would be available at the port along with the RF signals.
Bias Tee Setup in VNA Mode
Additional information for Option 10 is provided in the Vector Network Analyzer Measurement Guide (refer to Measurement Guides).
Bias Tee in SPA Mode
When bias is turned on, the bias voltage and current are displayed in the Instrument Settings Summary area of the window. The 12 VDC to 32 VDC power supply is designed to continuously deliver a maximum of 6 watts.
The bias tee menu can be accessed from the Application Options menu in SPA mode:
System > Application Options > Bias Tee
Bias Tee Menu
Bias Tee: Toggles On and Off the variable power supply.
Bias Tee Voltage: Use this submenu to set the power supply voltage.
Current: Toggle the bias tee current between Low and High.
Back: Press this submenu key to return to the Application Options menu.
