The Pico TA338 Premium 8.5 GHz Flex-Form Test Lead, N(m)-PC3.5(m) is designed for engineers, RF laboratories, metrology applications and vector network analyzer users who require a stable, repeatable RF connection during precision measurements.
The TA338 is part of Pico Technology's premium PC3.5 test lead range and is recommended for the PicoVNA 100 Series. Its flex-form construction is designed to provide improved phase and amplitude stability when the cable is repositioned during calibration and measurement.
Pico Technology specifies the TA338 with:
- Order Code: TA338
- Performance Grade: Premium
- Frequency Capability: Up to 8.5 GHz
- Impedance: 50 Ω
- Connector 1: N-type Male
- Connector 2: PC3.5 Male
- Length: 600 mm
- Construction: Flex-form
- Dielectric: Low-density PTFE
- Gauge: 270 μm
- Diameter over Jacket: 7.5 mm
- Loss: 0.6 dB at 6 GHz and 0.7 dB at 8.5 GHz
- Phase Stability: 0.8° at 6 GHz and 1.1° at 8.5 GHz
- Amplitude Stability: 0.05 dB
Premium Phase-Stable RF Test Lead
In vector network analysis, movement of a test cable between calibration and DUT measurement can introduce changes in electrical length and loss.
The TA338 is designed to reduce these effects by providing greater phase and amplitude stability when flexed.
Pico specifies cable stability by comparing the cable in a straight condition with the same cable formed into one complete 360° turn around a 10 cm mandrel.
Under this defined test condition, the TA338 provides:
- Phase variation: 0.8° at 6 GHz
- Phase variation: 1.1° at 8.5 GHz
- Amplitude stability: 0.05 dB
These characteristics make it suitable for VNA applications where the test lead may need to be repositioned between calibration and measurement.
Low Loss at High Frequencies
Cable attenuation directly affects the available signal level in RF measurement systems.
The TA338 provides specified insertion loss of:
- 0.6 dB at 6 GHz
- 0.7 dB at 8.5 GHz
The relatively low loss helps preserve signal level across the cable when performing high-frequency transmission and reflection measurements.
Loss introduced by the test lead can normally be corrected as part of a properly performed VNA calibration, but good cable performance remains important for maintaining dynamic range and measurement repeatability.
Flex-Form Cable Construction
Unlike a highly flexible cable that moves freely after positioning, Pico's premium flex-form cable is flexible but tends to hold its shape until deliberately moved.
This characteristic is useful for:
- Fixed laboratory test benches
- Repetitive DUT measurements
- Production test fixtures
- Calibration setups
- Measurements where cable position should remain stable
Holding the cable in a consistent position can help reduce measurement changes caused by unintended cable movement.
PC3.5 Male Measurement Port
The DUT-side interface of the TA338 uses a PC3.5 male connector.
Pico uses PC3.5 connectors on its premium VNA test leads because they are suited to precision RF measurement applications.
The PC3.5 male interface is useful when measuring compatible devices with:
- PC3.5 female ports
- Compatible SMA female interfaces
- Compatible K-type / 2.92 mm female interfaces
Connector compatibility should always be checked before mating precision RF interfaces, and correct connector torque should be used.
N-Type Male Instrument Connection
The opposite end of the TA338 uses an N-type male connector, providing connection to compatible VNA test ports and RF measurement equipment.
For PicoVNA systems, this arrangement creates a precision PC3.5 male measurement interface while maintaining the required N-type connection at the analyzer side.
50 Ω RF System
The TA338 is designed for 50 Ω RF measurement systems.
This makes it suitable for standard RF and microwave environments including:
- Vector network analyzers
- RF measurement systems
- Microwave test benches
- Calibration setups
- RF component characterization systems
- Laboratory and production test equipment
Maintaining a consistent 50 Ω signal path helps reduce reflections caused by impedance discontinuities.
PicoVNA 100 Series Compatibility
The TA338 is a recommended premium test lead for the PicoVNA 100 Series, including compatible 6 GHz and 8.5 GHz vector network analyzer configurations.
Pico's recommended premium measurement configurations use:
- TA338: PC3.5 male measurement port
- TA339: PC3.5 female measurement port
This allows users to select the required test-lead gender according to the connector configuration of the DUT.
S-Parameter Measurements
The TA338 can be used for common vector network analyzer measurements including:
- S11 input reflection
- S21 forward transmission
- S12 reverse transmission
- S22 output reflection
- Return loss
- Insertion loss
- VSWR
- Impedance measurements
- Phase measurements
Its stable phase and amplitude behaviour is particularly useful where measurements are repeated after cables have been repositioned.
Calibration and Measurement Repeatability
For accurate VNA measurements, calibration should be carried out at the intended measurement reference plane.
After calibration:
- Avoid unnecessary movement of the test lead
- Keep cable routing consistent
- Use the correct connector torque
- Keep RF connector interfaces clean
- Inspect connectors for wear or damage
- Avoid sharp bends or excessive mechanical stress
The TA338's flex-form construction helps maintain the selected cable position during subsequent measurements.
Typical Applications
The Pico TA338 is suitable for:
- Vector network analyzer measurements
- S-parameter testing
- RF component characterization
- Microwave measurements
- Filter testing
- Amplifier characterization
- Attenuator measurement
- Cable and interconnect testing
- Antenna matching and tuning
- RF module validation
- Network metrology
- Laboratory calibration setups
- Research and development
- Production RF testing
- High-frequency electronics validation
