The recently launched head end amplifier from the Philips Switchline GII range has proved to be a popular option for installers requiring a low cost, cascadable solution for small and medium sized line powered systems.

The Amplifier 9244U can be used instead of the Amplifier 9444 where a maximum of 2 Amps line power feeding current is required. Whereas the existing Amplifier 9444 requires the use of one or more amplifiers to provide current for line power feeding, the new Amplifier 9244U has a 2 Amp line power feeding supply built into it as standard. This makes it the ideal choice where line power feeding requirements are low and unlikely to increase in the foreseeable future.

It covers bandwidth 950-2150MHz and has a gain of 24-30dB (24 at 950MHz and 30 at 2150MHz). The unit's maximum output level is 114dBuV (2 Channels) and 102dBuV (30 channels). It has a noise figure of 10dB with an attenuation adjustment of 15dB (on each output). The LNB supply is 400mA and the physical layout of the unit is the same as the Amplifier 9444.

For bigger systems the 5 input range has the ability to supply large collective housing. 120 points off a single headend amplifier (AMP94444) is easily achievable with 2 line amplifiers (AMP9853 ), 2 power supplies (AMP8331) and 10x12 output switches (SWI6512) with a 50-60 metre subscriber drop cable

The range of GII equipment was designed with the specific requirements of the UK market in mind. MATV systems in the UK are typically fed from a single amplifier with one power supply. When the system is upgraded to IRS, adding additional power can be expensive, but by using a line powered system, the overall cost of the installation can be considerably reduced.

Digital terrestrial transmission (DTT) also played a major part in the development of Switchline GII. Up until now, most of the systems available had been designed to give an analogue terrestrial signal at the wall outlet of 60dBµV. However, because DTT signals are typically 20dB lower than analogue, the level required at the wall outlet for analogue is now closer to 70dBµV to give a digital level of around 50dBµV.

Through the development of the GII range, Philips have been able to deliver good quality signals with a high output level. This is achieved by using active switches which have between 0 and +4 db gain as well as high output level capabilities. The terrestrial signal is kept separate from the satellite IF signal and is diplexed with the satellite signal in the switch, allowing better control of the UHF signal through the system.

All the input levels to the switches can be individually adjusted with built in variable attenuaters, giving maximum control over the output signal. Each switch then only requires to be fed from one tap value and the adjustment is done on the switch and not by graded taps.

The Switchline GII range offers high quality 5 and 9 input systems with a range of switch output option. It enables installers to choose the right product for each application and position the switches anywhere in the building not just where power is available. Long drop lengths can also be achieved due to the high output levels.