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Bias Tee Maintenance


It includes specifications as well as a list of measures that should be taken when using bias tees.The precision K250 and V250 Bias Tees were developed for applications that involve the application of both dc and RF signals to a system under evaluation. They’re particularly well-suited to measuring active devices. Test devices can be exposed to DC voltages of up to 30 volts at 0.5 amperes with no impact on RF output. Low RF throughline loss (dB) and return loss ensure that measurements up to 60 GHz have no impact. The input port is isolated from the applied bias voltage by an RF input dc block.

ANRITSU K250 and V250 Bias Tees are high-quality, precision laboratory instruments that should be handled with the same care and consideration as other components of this kind. Following the precautionary notes below would allow a longer component life and less downtime due to connector failure. Furthermore, such compliance guarantees that RF component failures are not triggered by misuse or abuse, two failure modes that are not protected by the ANRITSU warranty.Before mating, check the pin depth of the connector with the RF part. Using an ANRITSU Pin Depth Gauge or an equivalent (Figure 2, Table 1). Destructive pin depth on mating connectors is the leading cause of failure in the sector, according to RF components returned for repair. If an RF component connector is mated with a connector with a destructive pin depth, the RF component connector is likely to be affected.

To control remote antenna amplifiers or other equipment, a bias tee is used to inject DC power into an AC signal. It’s normally located at the coaxial cable’s receiving end to transfer DC power from an external source to the coaxial cable that leads to the controlled unit. A bias “T” consists of a feed inductor on the system side to deliver DC to a connector and a blocking capacitor on the receiver side to prevent DC from passing through. Only the blocking capacitor is in series with the RF signal as it passes from one connector to the other. If the reverse supply voltage is applied, the internal blocking diode protects the bias “T.”

Bias tees are used for a number of purposes, but they are most widely used to provide an RF signal and (DC) power to a remote system where running two separate cables would be inconvenient. Biasing is commonly used for photodiodes (both vacuum and solid state), Microchannel plate detectors, transistors, and triodes to prevent high frequencies from leaking through a typical power supply rail. Noise from the power supply, on the other hand, does not appear on the signal line. Power over Ethernet, active antennas, low-noise amplifiers, and down converters are some other examples.

Connectors should not be overtorqued. Overtorquing connectors can cause damage to the connector’s centre pin. When tightening connectors, never use pliers.

Mechanical Shock should be stopped. RF components are designed to last for years under standard bench conditions. Do not, however, drop or otherwise misuse them. They are laboratory-grade devices that, like all other devices of this kind, must be treated with care.

Maintain the cleanliness of the Bias Tee Connectors. Dirt and other contaminants adhering to connector interfaces can easily disrupt the precise geometry that enables the RF part to work so well. Keep the connectors protected when not in use


The customer should not attempt any maintenance other than washing, according to ANRITSU. If the bias tee needs to be fixed or serviced, it should be returned to ANRITSU.

Cleaning K Connectors with a cotton swab and alcohol is a common approach that can split the male connector pin on precision connectors. The explanation for this is that the cotton swab is greater in diameter than the connector (the area between the inner wall and the centre pin).

We still suggest using a cotton swab, but you must trim it before putting it into the connector.Any safety precautions tee with a bias:When attaching to other gadgets, use either the finger saver that came with the bias tee or a 5 inch-pound torque wrench. There are no other resources that are recommended.To tighten ties, always spin the coupling nut. The connector interface is prematurely worn when the connector body is spun.

Do not mess with the connector’s centre pin. Improper cleaning of the inner connector with a cotton swab or other probe (see above) can cause the centre conductor to hinge on its bead, weakening or shearing the internal connection.A precision tolerance of mils (1/1000 inch) is measured on the centre pin of an RF component connector, while connectors on test devices that mate with RF components may not be precision types. It’s likely that their pins aren’t deep enough. To ensure suitability, they must be weighed before mating. If the test system connector measures out of tolerance in the “+” area when gauging pin width, the centre pin is too long. The RF part connector would most likely be damaged if it is mated in this state. The centre pin, on the other hand, is too short if the test system connector measures out of tolerance in the “–” area. While this will not cause any damage, it will result in a bad connection and, as a result, a performance degradation.

Elen David is a Managing Editor working in California. She writes about the past of the internet, consumer-facing technology, and social media. Jordan is the programming director for the world-famous Disrupt conference and flagship event. You may recall her from her appearances as the event’s host and moderator of panels and fireside chats.She is now working as a Managing Editor for Eravant Tech company.