Spectracom Corporation
8194B, 8195B, 8197B
GPS Ageless Master Oscillator Instruction Manual
2-3
2.3.1 Cable
Lengths
Using Spectracom CAL7xxx or LMR-400 coax, the maximum antenna cable length
permitted is 200 feet. These cables attenuate the GPS signal by 5.4 dB per 100 feet of
coax. Installations requiring longer antenna cables may use the Model 8227 Inline
Amplifier or lower loss cable. Refer to Section 2.5 for additional information on the
Model 8227 Inline amplifier.
When selecting alternate antenna cable sources, the attenuation characteristics at the
GPS frequency of 1575.42 MHz must be known. To ensure optimum receiver
performance, the total antenna cable attenuation must not exceed 12 dB. Cable
attenuations greater than 12 dB require the use of a Model 8227 Inline Amplifier.
2.4
Model 8226 Impulse Suppressor
Spectracom recommends the use of an inline coaxial protector for all products with an
outside antenna. Spectracom offers the Model 8226, Impulse Suppressor, to protect
the receiver from damaging voltages occurring on the antenna coax. Voltages
exceeding the impulse suppresser trip point are shunted to the system ground. The
Model 8226 is designed to withstand multiple surges.
Install the suppressor indoors, preferably where the coax enters the building.
Connect the largest gauge grounding wire available to the Model 8226 ground stud.
Optionally the suppressor can be mounted to a grounding panel or bulkhead using the
BF adapter bracket as shown in Figure 2-2. Spectracom offers the bracket under part #
MP10-0000-0002.
Figure 2-2 Model 8226 Impulse Suppressor
