ARNAV RCOM-100, Installation Manual

ARNAV Systems, Inc. 

5

Document No. 570-8050B 

27 November 2002 

The tables below identify different coax cable types that can be used and shows minimum and 
maximum cable lengths for that coax type.  Any other quality coax type can be used as long as 
the signal loss falls between the minimum and maximum db requirements. 
 
 
 

Table 3-1 Transmit Cable Lengths 

 
Part Number 

Cable 
Outside 
Diameter in 
Inches 

Bend Radius 
in Inches 

Minimum 
Length in 
Feet 

Maximum 
Length in 
Feet 

Cable Loss 
per foot 

ECS Cable 

    311901 

0.195 

1 

4.4 

11 

0.1513 

    311601 

0.229 

1.15 

3.7 

9.4 

0.1768 

    311501 

0.229 

1.15 

7.5 

18.9 

0.0877 

Table 3-2 Receive Cable Lengths 

  
Part Number 

Cable 
Outside 
Diameter in 
Inches 

Bend Radius 
in Inches 

Minimum 
Length in 
Feet 

Maximum 
Length in 
Feet 

Cable Loss 
per foot 

ECS Cable 

     311901 

0.195 

1 

5.7 

35.7 

.2 

     311601 

0.229 

1.15 

8.2 

51.5 

.13850 

     311501 

0.229 

1.15 

10.3 

64.3 

.11100 

GPS antenna proximity to transmit/receive antenna: 

 
Due to potential transmit power saturation of a GPS antenna input, there must be a minimum 
separation between any GPS antenna and the transmit antenna.  For a typical active GPS 
antenna for aviation the minimum separation should be 2 feet.  For least interference between the 
antennas a preferred distance between antennas is 4 feet.  The preferred distance may not be 
practical on aircraft installations so every effort should be made to provide the most separation 
that circumstances permit.  
 
NOTE:  Some GPS antennas provide a filter prior to the pre-amp that helps provide more 
rejection of non-GPS frequencies.  If the GPS antenna can provide additional filtering the 
separation requirement can be reduced.  In any case the GPS performance must be verified 
during the post-installation ground check. 
 
 
When routing the coaxial cables make sure to identify the cables so they can be connected to the 
proper location.  There are 2 cables with TNC connectors on both ends and all appear to be the 
same.  
 
Once the antennas and RCOM-100 locations have been verified to meet the above restrictions 
the installation can proceed. 
 
 
 For mounting location in the Cessna 180 series aircraft refer to drawing ENG-5021.  The shown 
locations for Antenna, and RCOM-100 comply with the requirements listed above.  If the exact 
locations on drawing ENG-5021 are used, the drawing also shows information for weight and 
balance calculation.