Ericsson ORION, Installation Manual

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2.
Use the formula:
1
/
4
λ
in = 2805
F(MHz)
Example 1: Assume the customer has an 800 MHz ORION with most of
the transmit frequencies between 816-821 MHz. Therefore, center frequency
is 818.5 MHz. Applying the above formula results in:
1
/
4
λ
in = 2805 = 3.43 inches
818.5
1
/
2
λ
wavelength (in inches)= 6.85 inches
The cable length should be 3.43 + n x 6.85 inches. Since the installer will
need a length of the coax from the OM series antenna to the radio to be at least
22 inches long to physically connect the antenna to the radio, he must calculate
a length of coax that will meet the odd quarter-wavelength requirement and be
greater than 22 inches.
Choose n=3. Coaxial cable length is 3.43 + 3 x 6.85= 23.99 inches.
Example 2: Assume the center frequency is 155 MHz. Applying the
formula:
1
/
4
λ
= 18.10 inches;
1
/
2
wavelength = 36.19 inches; n=1.
Coaxial cable length is 18.10 + 1 x 36.19= 54.29 inches.
Antenna Installation
1. After the proper length of coax cable has been calculated, cut the coax
cable (provided by Larsen) so that when the TNC crimp style con-
nector is installed the overall length will equal the calculated length.
2. Route the assembled proper length coax from the antenna, under the
antenna bracket, and into the weather-resistant case.
3. Connect the antenna cable to the RF port on the ORION radio.
FINAL CHECKS AND CONNECTIONS
After the weather resistant case is installed, all cables run, and the radio,
control unit, speaker, and microphone installed, refer to the interconnection
diagrams and verify that all connections have been made and the equipment is
properly grounded. Make a final check of all cables to make sure they are
30
Figure 5 - Radio Installation, Harley-Davidson Motorcycles
(188D6803, Sh. 1, Rev. 2A)
15