PCT International’s RF amplifiers are available in a number of different configurations, and are designed to meet the needs of many different applications. PCT RF amplifiers are manufactured to have excellent performance and are of the highest quality. They meet all industry standards and specifications including those developed by the Society of Cable Telecommunications Engineers (SCTE), who creates international standards for many TV signal distribution products.
PCT’s professional grade RF amplifiers can be used for HDTV, CATV, off-air, analog, and digital RF distribution applications, or in any application that requires consistent reliability and high performance.
An RF amplifier is designed to amplify the strength of received signals so that they will overcome the signal losses in the RF distribution system. Since coaxial cable loss increases with length, centrally locating the RF amplifier in relation to the distribution coaxial cables will help ensure that all of your outlets receive the proper signal strength.
PCT’s superior quality RF amplifiers support both analog and digital broadcast signals up to 1002 MHz. They are available with one-way (1-Port),
and eight-way (8-Port)
outputs, which have the lowest distortion performance available. In addition, PCT RF amplifiers have a powder coated cast aluminum housing, are weather sealed for corrosion resistance, and have precision machined SCTE conforming sealed "F" ports, and come standard with the patented Digital Seizure Mechanism (DSM), which provides significant advantages in center conductor retention, surface contact area, electrical performance, and surge resistance. PCT RF amplifiers can be used either indoors or outdoors.
PCT RF amplifiers come in many different configurations. Following is a description of the different configuration options currently available.
Number of output ports
RF amplifiers that are normally used inside customer homes are made with one-way (1-Port),
and eight-way (8-Port) output ports. All of the ports of an amplifier will have the same signal strength output, but the actual amount of gain is determined by the number of output ports on the amplifier. In most cases, in-home RF amplifiers have a fixed amount of gain, but as the output signal is split into more outputs, there is less available signal at each port. As an example, in a 1-way amplifier, all of the gain (100%) of the amplifier will be at the output port. With a 2-way amplifier, because of the splitter on the output, only half (50%) of the amplifier gain will be at at each output port. For a 4-way amplifier, the signal is divided four ways, so there only one quarter (25%) of the signal is available at each output port. For an 8-way amplifier, only one eighth (12.5%) of the available signal is at each output port.
Graphically, it looks like this:
This situation will be the same whether the amplifier has multiple outputs, or only has one output and an external splitter is attached to that output.
Return Path Capability
Most cable telecommunications networks are considered two-way networks, which means that the cable modems, Multimedia Terminal Adapters for cable telephony (MTAs), and set top boxes all transmit signals back into the cable network in order to have two-way communications. The signals are sent back into the cable network in the 5 to 42 MHz range, which is called the return path. PCT RF amplifiers are all two-way capable, which means they will pass signals in the return path back to the cable network. There are three types of return path options available: passive return, active return, and unity gain return.
A passive return distribution amplifier does not have any amplification for signals in the return path frequency range (5-42 MHz). This is the most commonly used in-house RF amplifier by cable operators. In most cases, the cable modem or MTA is capable of putting out enough signal level to overcome any signal losses in the home, so amplification in the return path is not required. However, the signals in the return path will lose strength as they pass through the coaxial cable and RF splitters in the house. The return path signals will lose strength if there are too many splitters between the cable modem and the connection point to the cable network at the home. Each time the return path signals go through a splitter, about half of its power is lost due to the insertion loss of the splitter. Cable modems are capable of putting out high enough signal levels to compensate for most of this loss, but if there are too many splitters, there may not be enough return path signal strength to get back into the cable network at the necessary signal level. If this occurs, the cable modem or MTA will not be able to communicate back through the cable network and those services will not work properly. In these situations, the best solution is to use an RF amplifier with active return. This will amplify the signals and help to overcome this excessive loss in the network.
An active return RF amplifier will include amplification for the signals in the 5 to 42 MHz range, as well as gain for the normal TV signals in the 54 to 1002 MHz range. This will be used in situations where there are many outlets in a home, or long coaxial cable runs, causing an excessive amount of loss in the return path frequency range.
Another type of active return RF amplifier is called a Unity Gain amplifier. In this case, the amplifier in both the forward path and the return path has just enough gain to compensate for the loss of the internal splitter network in the RF amplifier. A “standard” active return RF amplifier will normally have a gain of either 10 dB or 15 dB, regardless of the internal splitter network in the amplifier. A unity gain amplifier will have gain equal to the loss of the internal splitter network. So, a 2 port unity gain amplifier will have 4 dB of gain. Since the loss of the internal 2-way splitter required to provide two output ports is 4 dB, and the gain of the amplifier is 4 dB, the net gain is 0 dB (4 dB gain minus 4 dB loss), or “unity gain”. A four port RF amplifier will have approximately 7.5 dB of gain to overcome the 4-way splitter loss, and an eight port amplifier will have 10.5 dB of gain to overcome the 8-way splitter loss. In all cases, the gain minus the loss equals 0 dB, so they are considered unity gain amplifiers.
In cable telephony installations, it is necessary to ensure that, even if power is lost, the Multimedia Terminal Adapter (MTA), which is the interface between the telephones in the home and the cable operator’s network, can still send and receive signals so emergency telephone calls can still be made. PCT Bypass RF amplifiers are specifically engineered for use in cable telecommunications networks providing cable telephone services. They will have a port that is specifically marked as the “bypass port”, frequently by saying “To eMTA” on the label. Although it can be used to provide signals to a TV set, this port is specifically designed for the cable modem or the MTA (Multimedia Terminal Adapter – the device cable operators use to provide cable telephony service) as it always has signal, even when the power is lost.
There are two basic types of bypass amplifiers: active bypass and passive bypass. The PCTVB series bypass amplifiers are considered active bypass amplifiers. There are two relays that will route the signal around the amplifier if power is lost. When the unit is powered, the TV signals go directly into the amplifier in the normal fashion, and the MTA or cable modem is connected to the designated bypass port. If power is lost, the relays transfer the signals over to the bypass path, which goes around the amplifier and directly to the designated bypass port. This ensures that emergency telephone calls can be made even when power is lost.
The PCTVC series bypass amplifiers are considered passive bypass amplifiers. There is an internal two-way splitter directly on the input port of the amplifier housing. One output of this splitter goes directly to the bypass port, and the second output of the two-way splitter provides the input to the actual amplifier. This ensures that emergency telephone calls can be made even when power is lost.
All PCT Bypass RF amplifiers are professional grade and meet stringent US and international standards, including those developed by the Society of Cable Telecommunications Engineers (SCTE), who creates international standards for many TV signal distribution products.
RF amplifiers will increase the TV signal levels by a designed amount. This is called amplifier gain and it is given in dB. Most RF amplifiers have a fixed 15 dB of gain. But, when an amplifier has multiple outputs, it will have internal splitters that cause signal loss, or negative dB. In a two output RF amplifier, there will be a 2-way splitter on the output of the amplifier, which divides the signal into two output ports. Each output port has approximately 50% of the signal level coming out of the amplifier. The signal level will drop by approximately 3.5 dB on each port. The effective gain of this amplifier is 15 dB of gain minus 3.5 dB of splitter loss, or 11.5 dB of gain from the input port to each output port.
A four port amplifier includes a 4-way splitter on its output. Each output port will have 25% of the power, and the signal level will drop by approximately 7.5 dB. If an RF amplifier has 15 dB of fixed gain, a four output RF amplifier will have an effective gain of about 7.5 dB per port (15 dB gain minus 7.5 dB splitter loss) from the input port to the output port(s).
An eight port amplifier has an 8-way splitter on its output. Each output will have 12.5% of the power, and the signal level will drop by approximately 11 dB. An eight port RF amplifier with 15 dB of fixed gain, will have an effective gain of about 4 dB per output port (15 dB gain minus 11 dB splitter loss).
PCT also provides specialty RF amplifiers that have 10 dB of gain, 20 dB of gain, and variable gain. These are used in special cases where different amounts of gain are required.
A power inserter is used to back feed power to the RF amplifier through one of the RF output ports. This allows the amplifier to be mounted at a location where power is not available. In most installations, it will not be necessary to use the power inserter since the amplifier is usually mounted near a power outlet. There are no performance advantages to using the power inserter – it is only used to allow the unit to be remotely powered when the amplifier can’t be located near a power outlet.
In addition to RF amplifiers designed for use in single family homes, PCT also manufactures a high quality amplifier for apartment buildings (also called MDUs, or Multiple Dwelling Units). MDU amplifiers have more signal gain (32 dB), include a high efficiency internal switching power supply, independent input and output test points, and have the ability to adjust the input and output levels on both the forward and return path through the use of plug in attenuators and equalizers. It is designed to be wall mounted, which makes it ideal for MDU applications.