A transponder is a subsystem that provides the connecting link between the transmission and reception antennas of a satellite or aircraft. It is among the most important subsystems within the aerospace and aviation segments. A transponder effectively performs the functions of both a transmitter and receiver/responder in a satellite. Therefore, the name ‘transponder’ comes from the combination of transmitter and responder.
 
Transponders perform two main functions. The first is to amplify a received input signal, and the second is to translate the frequency of the signal. Generally speaking, differing frequency values are chosen for both uplink and downlink in order to prevent interference between the transmitted and received signals. The process of a signal moving through a transponder looks like this:
 
Satellite/Antenna > Duplexer > Low Noise Amplifier > Carrier Processor > Power Amplifier > Duplexer > Satellite/Antenna
 
This is a basic explanation of a transponder’s operation, but let’s take a look at each part. The satellite or antenna receives a signal and sends it to the duplexer. The duplexer is a two-way microwave gate that receives the uplink signal from the satellite antenna. The signal then moves to the low noise amplifier (LNA) which receives the weak signal and amplifies it. The carrier processor then performs the frequency down conversion of the received signal. The function of this block determines the type of transponder. The power amplifier then amplifies the power of the frequency down-converted signal to the required level and sends it back to the duplexer. From here, the duplexer transmits the downlink satellite to the antenna, which finally responds by outputting a signal.
 
As stated, the function of the carrier processor determines the type of transponder. There are two types of transponders. These are bent pipe transponders and regenerative transponders. Bent pipe transponders receive microwave frequency signals. They convert the frequency of the input signal to RF frequency and subsequently amplify it. Bent pipe transponders are also referred to as repeaters and conventional transponders. They are suitable for both analog and digital signals.
 
Regenerative transponders perform the functions of frequency translation and amplification just as bent pipe transponders do. The difference is that, in addition to these two functions, regenerative transponders also perform the demodulation of the RF carrier to baseband, regeneration of signals, and modulation. Regenerative transponders are also known as processing transponders. They are only suitable for digital signals, but offer the advantages of improved signal to noise ratio (SNR) and improved flexibility of implementation.
 
Transponders first came into use to help military authorities identify friendly aircraft, which would transmit a coded signal when interrogated by military radar. This practice was known as IFF, or Identification Friend or Foe. Transponders have since become popular in civil aviation as well, where it is standard practice to allocate a specific transponder code to each aircraft in controlled airspace. This allows authorities to identify specific aircraft on crowded radar screens using secondary surveillance radar. Transponders are critical to air traffic management, where they are used for many purposes including aircraft identification, enhancement of the controllers’ situational awareness, and development of air traffic control tools and safety nets.
 
For all types of transponders and their associated parts, look no further than Jet Parts 360. Owned and operated by ASAP Semiconductor, we can help you find all types of parts for the aerospace, civil aviation, defense, electronics, industrial, and IT hardware markets. Our account managers are always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@jetparts360.com or call us at 1-708-387-7800. Let us show you why we consider ourselves the future of purchasing.

Valves are common components for a great number of systems, allowing for various devices to control the flow of fluids. Depending on the particular application, the types of valves used for assemblies will often depend on particular needs and requirements. With a valve type known as the disk valve, the flow of fluids can be regulated with its ability to restrict or completely obstruct flow. While simplistic by themselves, disk valves are often a closure device for larger assemblies, assisting operations as parts of check valves, gate valves, butterfly valves, and other such types. With a variety of sizes, actuation methods, and other characteristics available, disk valves can serve a number of systems and uses.
 
The operation of the disk valve assembly will often depend upon the device that it is a part of. Nevertheless, the valve disk regularly serves as the primary pressure boundary of a system, and its positioning will dictate the flow of fluids. As valve disks will often be tasked with impeding the flow and force of fluids while in a sealed position, such components are manufactured with hardened metals for increased strength. To ensure that the disk is able to close itself with force, various disk valve actuator assembly parts may be used. As disk valves can differ in their basic operations depending on their type, it can be useful to know about the most common variations that are used across industries. Generally, the three primary types of disk valve assemblies are butterfly valves, disk check valves, and sanitary disk valves.
 
With the butterfly valve type, a disk is used in order to completely shut off a pipeline as needed. Similar to disk valves in general, the butterfly valve type has many designs and arrangements, though the most common are the zero offset, double offset, and triple offset variants. The zero offset type best serves devices exhibiting up to 200 psi and 400 degrees Fahrenheit, and they utilize a disk that can rotate within the middle of the pipe. With the double offset type, higher performance and pressure handling is achieved with the use of two offset stems that create a cam action upon movement of the disk. Triple offset valves have three offset stems for their assembly, and this allows them to create a uniform seal that is frictionless.
 
With the disk check valve type, such components allow for non-return or non-reverse flow. As a disk valve assembly that provides checks for a system, such valves ensure that fluids can not move backwards once they have surpassed a certain point. In order to close off the valve, components such as spring-loaded, tilting, or folding disk rotary mechanisms may be used. With any of the aforementioned methods of shut off, the valve disk itself functions to prevent any possible backflow.
 
The sanitary valve has functions that are very similar to the other types, though its difference lies in the fact that they are used for ensuring sanitation and abiotic conditions. With a rounded disk for the assembly, fluids can flow through the valve smoothly. With various types available such as the ball disk valve or clamp disk valve, sanitary disk valves are regularly found in applications dealing with beverages, food, chemicals, pharmaceuticals, dairy, and more. To ensure their optimal functionality and robust characteristics, such valves are regularly manufactured from stainless steel.
 
With the various types of disk valves available, a number of systems can benefit from the ability to slow or impede the flow of fluids. Jet Parts 360 is a trusted distributor of aircraft parts and other aerospace components, and customers can compare quotes for every aviation product that we offer. If there are particular items from our inventory that you are interested in, we ask that you fill out and submit an Instant RFQ form as provided on our website, and a dedicated account manager will reach out to you in 15 minutes or less to provide a unique solution to your needs.

            For the correct functionality of a piston powered combustion engine, the camshaft must be able to control valves with precise timing to ensure proper fuel and air mixtures for ignition. To control valves, the camshaft relies on a component known as a lifter or tappet. In recent years, a component known as the roller lifter/tappet has begun to replace more conventional types due to their characteristics. As compared to alternative components such as the flat tappet assembly, the camshaft assembly roller lifter provides increased power advantages, smoother engine operations, and causes less friction between moving parts. As such, the roller lifter is an advantageous component for aircraft engines.
 
            For the more traditional flat aircraft engine, the camshaft relies on lobes and other assembly parts in order to actuate intake and exhaust valves for engine operation. In order for the cam lobes to govern valves, they spin a component known as a lifter, which then acts through rocker arms to open and close valves. The point at which the lifter and the lobe meet is a flat surface, and the cam lobe swipes across this surface so that the lifter can spin. By replacing the flat tappet with a roller lifter, the rounded shape allows for easier lifting over lobes so that less friction results from the movement. While being a small change to the entire assembly, the reduction to friction provided by such a configuration makes roller lifters very beneficial for use in automobiles. For aircraft, on the other hand, such concerns are not as common as the low friction characteristics of roller tappets may not be convincing enough for an operator to make the change.
 
            For aircraft that have either Lycoming or Continental engines, however, spalling is a common concern that can affect the health and performance of the engine. Spalling is often the result of corrosion due to moisture, and cam and lifter components are highly at risk. If cam and lifter surfaces begin to corrode, high amounts of friction can result until lobes are completely removed. In such occurrences, the camshaft and engine assembly can rapidly lose performance.
 
            While the roller lifter or tappet is just as susceptible to the forces of corrosion, its difference lies in the fact that the roller ball slides over the camshaft lobe rather than dragging along a face. As such, the degree to which the tapper is damaged due to friction and corrosion is less as compared to their flat tappet counterparts. For performance, on the other hand, there is little change that warrants a complete switch if such characteristics are a primary concern. Nevertheless, many pilots have claimed to find benefits in the roller tappet assembly.
 
            As a newer technology, roller lifters have a potential to become a standard with the improvements they offer to engine operations. Nevertheless, further industry testing will be required before more conclusive results can be found. As such, budgets, performance needs, and other factors may decide whether making the switch to the roller lifter is worth it for your particular aircraft and requirements.
 
            At Jet Parts 360, we are a trusted distributor of aircraft parts and other aerospace components where customers can compare quotes for every aviation product we offer. Whether you are searching for a spring tappet, shell tappet, tappet band lever, or another aircraft engine component, we can help you secure everything you need with competitive pricing. To begin the purchasing process at any time, customers may fill out and submit an Instant RFQ form as provided on our website. With the details we receive from your request, our team can quickly craft a personalized quote based on your individual needs and requirements. Experience why customers trust Jet Parts 360 for their operational needs today!