M e r i d i a n I I U s e r M a n u a l
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A P P E N D I X E
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M e r i d i a n I I U s e r M a n u a l
I N S T A L L I N G T H E G P S A N T E N N A
Long Cable Runs
Most devices are installed with only 50 feet (15 meters) of antenna cable. However, there are many
circumstances where 50 feet is inadequate. We can accommodate cable lengths up to 1000 feet using
a combination of low-loss cable and preamplifiers.
Recommended Cable
The factory-supplied GPS cable is an RG-59 type. RG-59 is a broad classification, with wide varia-
tion in performance between cables from different manufacturers and for different applications. We
supply two specific cables: Belden 9104 or Belden 1505A. Belden 9104 is constructed with a copper-
plated steel center conductor and an aluminum outer braid. Belden 1505A is constructed
of all solid copper conductors. Both cables are double shielded, low-loss cables designed for
the cable TV industry, and they both have a signal loss of 10 dB/100 feet at GPS frequencies. The
Belden 1505A also has very low DC resistance, which is important for long cable runs. For very long
cables, if the DC resistance is too high, not enough voltage will be available at the end farthest from
the Meridian II where the antenna and preamplifiers are installed. For cable lengths less than 700
feet, Belden 9104 is acceptable.
IMPORTANT
If you are supplying the cable for your GPS installation, then you must make sure the cable you install is
comparable to the Belden 9104 or Belden 1505A. Specifically, the cable must:
Be double-shielded
Have 10 dB or less of loss per 100 feet at 1.5 GHz.
Have very low DC resistance (for cable lengths > 700 feet)
Choosing an inferior cable type can cause a myriad of GPS reception problems.
Using GPS Low-Noise Amplifiers (LNAs)
For longer cable lengths, you will need one or more LNAs (see chart below). We produce the
G-LNA2 which is a very high-performance, low-noise, low-power drain, inline amplifier for difficult
GPS signal environments and long cable runs (greater than 250 feet of factory-supplied cable). The
following table shows the number of LNAs we recommend for each GPS antenna installation using
our factory-supplied cable. Installations using other cable types may have different preamplifer
requirements.
Summary of Contents for Meridian II
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