Page 4 of 7
Note:
When installing any electrical device always follow the rules prescribed by your
local electrical and building ordinances. Contact Symmetricom as described below for
additional technical recommendations for installation.
4.0 Considerations for Long Cable Runs
Due to process variations in the fabrication of the 58536A, the gain through the device can
vary
±
3 dB. Assume the worst case loss of the 58536A (
−
3 dB) when determining if line
amplifiers are necessary in your GPS antenna system. If an amplifier is required, consider
the
58529A line amplifier with L1 bandpass filter.
Note:
In general, an amplifier is required if there is more than 20 dB of cable loss
between the GPS antenna and the GPS receiver. Two amplifiers are recommended
when there is more than 40 dB of cable loss.
Calculate cable loss:
The assumed worst case loss through the 58536A (
−
3 dB) is equal to:
•
18 meters (60 ft) of cable length when using LMR 400 cable
•
8 meters (25 ft) of cable length when using RG-213 cable
Use this procedure to determine if line amplifiers are required:
1. First, calculate the distance from the antenna to the most distant receiver.
2. Determine the signal loss due to the type and length of cable used.
3. Add the assumed worst case loss through the 58536A in terms of cable length.
4. Compare the result to the requirements for line amplifiers below. If line amplifiers are
required, they should be added as close to the GPS antenna as possible (within 10
meters/33 feet).
5.0 Requirements for Line Amplifiers
This section provides information that will help you determine if line amplifiers are required
for your GPS antenna system installation.
For LMR 400 cable:
If the estimated cable length (include the cable length equivalent to the assumed worst case
loss through the 58536A) between the antenna and the most distant GPS receiver is:
•
Less than 115 meters (377 feet), no line amplifier is necessary.
•
More than 115 meters (377 feet) and less than 240 meters (787 feet), you need 1 line
amplifier.
•
More than 240 meters (787 feet) and less than 360 meters (1181 feet), you need 2 line
amplifiers.
•
More than 360 meters (1181 feet), contact Symmetricom for assistance.
To Next Page
Loading...
Need help?
General
