Connector Care

Proper use and care of the connectors on your vector network analyzer is important. Improper connections can result in damage to your device and invalid measurements. Follow the guidelines in this section to prevent damage and to make the best possible measurements.

Caution  NI is not liable for damage to NI VNA devices that results from improper connector care and signal connections.

Tighten Connectors Without Rotating the Center Pin

Never tighten the connectors, adapters, or cables such that the center pin rotates.

Avoid Touching Connectors with Bare Hands

Avoid touching Type-K connector mating planes with bare hands. Natural skin oils and microscopic dirt particles are difficult to remove.

Observe Pin Depth of Mating Connectors

Make sure to use the proper connectors to mate with the NI vector network analyzer. NI recommends that you use precision or instrument or metrology grade Type-K, 2.92 mm, 3.5 mm, or SMA connectors. Before mating the connector with another device or cable, measure the pin depth of the device that you want to mate with the RF component, using a pin depth gauge. Improper pin depth of mating connectors is a major cause of failure in the field. When an RF component is mated with a connector that has a center pin that is too long in respect to the reference plane of the connector, damage can occur to the RF component connector.

The center pin of RF component connectors has a precision tolerance measured in mils (1/1000 inch). Connectors on test devices that mate with RF components may not be precision types and may not have the proper depth. Therefore, measure these connectors before mating to ensure suitability. When gauging pin depth, if the test device connector measures outside the tolerances listed in the following table, the center pin is too long. These connections can damage the termination connector.

On the other hand, if the test device connector measures out of tolerance in the "–" region, the center pin is too short. While this connection does not cause any damage, it results in a poor connection and a consequent degradation in performance.

Avoid Lateral Pressure

Never put lateral pressure on the center pin of the connector.

Always Torque Connectors to 0.9 N · m (8 in · lb) Using a Torque Wrench

Do not overtorque connectors; doing so may damage the connector center pin. Always use a 0.9 N · m (8 in· lb) torque wrench when tightening 2.92 mm, 3.5 mm, and SMA connectors. Finger-tighten N-type connectors. Never use pliers.

Teflon Tuning Washers

The center conductor on most RF components contains a small teflon tuning washer. This washer compensates for minor impedance discontinuities at the interface. The washer location is critical to the RF component performance.

Caution  Do not disturb the teflon tuning washer in connectors.

Avoid Mechanical Shock

Precision connectors are designed to withstand years of normal bench handling. Handle the connectors carefully and avoid dropping them. Mechanical shock significantly reduces their service life.

Avoid Applying Excessive Power

Connector Cleaning Instructions

Connector interfaces, especially the outer conductors on the SMA connectors, should be kept clean and free of dirt and other debris.

Note  NI does not recommend using cotton swabs to clean the NI vector network analyzer connectors. Cotton fibers can become lodged in the connector, causing damage or measurement errors.

The following information includes important tips for cleaning connectors:

• Use only pure isopropyl alcohol as a solvent.
• Always use an appropriate size foam swab.
• Gently move the foam swab around the center conductor.
• Never put lateral pressure on the connector's center pin.
• Verify that no foam or other foreign material remains in the connector after cleaning.
• Only dampen the foam swab. Do not saturate it.
• Pure, filtered, compressed air can be used to remove foreign particles and to dry the connector.
• Verify that the center pin has not been bent or damaged.

Store Connectors Properly

When not in use, keep the connectors covered with the dust cap included in the NI vector network analyzer shipping kit.