Cellular (Tx/Rx) Led Indicator; Signal Strength - Campbell CR300 Series Product Manual

8.3 Cellular (TX/RX) LED Indicator

When the data logger is powered, the cellular LED will turn on according to cellular modem
communications states:
Off: Cellular modem off, insufficient power, or failure to establish a connection with the
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provider (periodic retries will occur).
Solid: Cellular modem is powering up and attempting to establish a connection with a
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provider.
Quick Flashing (approximately 1 second duration): Indicates successful network
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registration.
Flashing: Flashes with network activity.
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8.4 Signal strength

Signal strength may indicate the quality of connection to a cellular tower. For 3G networks, this is
reported as RSSl (Received Signal Strength Indicator). For 4G, it is RSRP (Reference Signal
Received Power).
Signal strength units are –dBm; –70 is a stronger signal than –100.
Table 8-1: Signal strength
RSSI (3G)
Quality estimate
Excellent -70 or greater -90 or greater
Good -71 to -85
Fair -86 to -100
Poor less than -100 less than -115
Because signal strength can vary due to multipath, interference, or other environmental effects, it
may not give a true indication of communications performance or range. However, it can be
useful for activities such as:
determining the optimal direction to aim a Yagi antenna
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determining the effects of antenna height and location
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trying alternate Yagi antenna (reflective) paths
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seeing the effect of vegetation and weather over time
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RSRP (4G)
dBm dBm
-91 to -105
-106 to -115
8. Cellular communications option 41