Low Noise Amplifier (LNA)
The TimeMachines GPS Low Noise Amplifier (LNA) product was created to both extend the length of cable that can be used between a time server and the outdoor antenna, as well as allow for a greater number of signal splits to occur downstream of the outdoor antenna.
Using the LNA to allow for more signal splits:
One common use for the LNA is to allow a single antenna to be split to multiple time servers. The 760-610-000 splitter is the model of choice. TimeMachines makes 2 and 4 port splitters. An ideal 2 port splitter will reduce the signal sent to each of its outputs, roughly in half (3dB loss), while an ideal 4 port splitter will reduce the signal to each port to be about ¼ of the original input signal (6dB loss). Since there are no ideal splitters, the loss per port is a bit worse. Depending on the length of the cable between the antenna and the splitter, the resulting loss of signal can start to cause issues when multiple splits are required. In this configuration, power can come from time server directly and no powered splitter is required. Care must be taken to ensure that a DC path exists between a time server and the LNA/Antenna. Confirming the LED is lit on the inside of the LNA can help verify this. Without power, the LNA and the amplifier on the antenna will not function and no signal will be received. No connector adapters are typically needed in this configuration when used with TimeMachines splitters. The LNA output port can connect directly to the input of the splitter.
Using the LNA to support longer cable runs:
The second common configuration for the LNA, is to extend cable length beyond the 250ft limit of the RG58/LMR-195 that TimeMachines sells. SKU 760-611-000 is available for this installation configuration and includes the required Type-N connector adapters.
An LNA is put in-line with the cable. Type-N female adapters are used. A typical spacing is every 250ft of cable. A 760-950-250 cable from the antenna to the first LNA works nicely. Additional runs of the 760-950-250 cable, with an LNA being used to join the cables allow for significant extension of the cable run. The upper limit of this arrangement is not known. As mentioned previously, the moment that a second LNA is introduced to the configuration, a Time Server will not be able to provide sufficient power to the LNA’s and a powered splitter will be required such as the 760-602-PWR or 760-604-PWR.