User's Manual

5.3 RF Output Settings
Consult Table 3 for the maximum applicable power settings. The NX915 is a multi-modem system offering both
Frequency Hopping Spread Spectrum and DTS transceiver modes in the license-free 902-928 MHz band. It
therefore has specific output power limits for each modem dependent on your installation. Since RF cable lengths
and cable types may vary from one installation to another it is critical to comply with the following:
The EIRP shall be calculated based on the transmitter antenna gain (G
dBi
), cable loss (CL
dB
) and Peak output
power at the antenna terminal (P
dBm
). Calculated EIRP = P
dBm
+ G
dBi
- CL
dB
 Never exceed the modem specific EIRP values listed in Table 3 for any given system loss.
Table 3. NX915 Max Power Settings
Max Power Settings for FHSS modes
Antenna Gain
(Antenna Gain in dBi
1
)
Modem
Selection
Peak Output Power
at Antenna Terminal
(dBm)
Cable Loss
(System Attenuation)
EIRP
2
(dBm)
6 (or less) Omni or Yagi 125 29.99 0.86dB 35.13
9.15 Omni Directional Antenna 125 29.99 3.86dB 35.28
12.15 Yagi Antenna 125 29.99 6.86dB 35.28
6 (or less) Omni or Yagi 250 29.99 0.86dB 35.13
9.15 Omni Directional Antenna 250 29.99 3.86dB 35.28
12.15 Yagi Antenna 250 29.99 6.86dB 35.28
Max Power Settings for DTS modes
Antenna Gain
(Antenna Gain in dBi
1
)
Modem
Selection
Peak Output Power
at Antenna Terminal
(dBm)
Cable Loss
(System Attenuation)
EIRP
2
(dBm)
6 (or less) Omni or Yagi 500 27.93 0.86dB 33.07
9.15 Omni Directional Antenna 500 27.93 1.86dB 35.22
12.15 Yagi Antenna 500 27.93 4.86dB 35.22
6 (or less) Omni or Yagi 1000 28.80 0.86dB 33.94
9.15 Omni Directional Antenna 1000 28.80 2.86dB 35.09
12.15 Yagi Antenna 1000 28.80 5.86dB 35.09
6 (or less) Omni or Yagi 1000W 29.62 0.86dB 34.76
9.15 Omni Directional Antenna 1000W 29.62 2.86dB 35.91
12.15 Yagi Antenna 1000W 29.62 5.86dB 35.91
1. Most antenna manufacturers rate antenna gain in dBd. To convert to dBi, add 2.15 dB.
2. Feedline loss varies by cable type and length. Installation specific compensation is required.