XM Satellite Radio XMD076A )

Installation Manual

XMD076A

XMD076A-3 Information is subject to the 10

Rev C, 06/22/06 restrictions on the title page

H E A D S U P T E C H N O L O G I E S

Table 1 - Cable Length Chart

RG Type

(Mil-C-17)

Loss Rating

(dB/100-Ft.)

@ 2.339GHz

Length Range (Ft.)

@ 8 - 12dB Loss

142 20.6 38.8 – 58.3

400 23.41 34.2 – 51.3

316 40.87 19.6 – 29.4

178 68.82 11.62 – 17.4

When antennas of other ga in values or other cable ty pes are installed, the ca ble length

can be determined using the equation below:

Antenna Gain – 22

Cable Length (Feet) = (Cable Loss Rating

(in dB/100-Ft.)

)

X 100

When the distance betwee n the antenna and receiver i s short, run the amount of ca b le

required to meet the loss requirement and stow excess length. An alternative to stowing

large amounts of excess cable is to install a low power RF attenuator in-line with the

cable. This system requires a DC bias passing type attenuator that has a frequency

rating that falls within the maximum satellite frequency of 2.345 GHz.

• Mount the antenna no closer than 36 inches to VHF-Comm transmitters of 15

Watts or less. For more powerful transmitting antennas, XM separation should be

a minimum of 48-inches. Installatio n pr e- testing (see note below) should be

performed if the separation is less than 60-inches.

If a XM/VHF-Comm combo style antenna is being installed and replacing the

operation of an existing approved antenna installation, the existing separations

are acceptable.

• SATCOM antennas transmit at 40 Watts and should be separated by the largest

distance possible, or a minimum of 36-inches.

• When routing the XM antenn a cable, the maximum possib le separation from

transmitter antenna feed cables must be considered, especially with SATCOM

and other high power transmitters. Antenna feed cables of VHF transmitters of 15

Watts or less should only require a minimal separation.