Campbell Scientific RF401-series and RF430-series Spread Spectrum Data Radios/Modems - Manual (Page 48)

RF401-series and RF430-series Spread Spectrum Radio/Modems
6. Troubleshooting
If you can’t connect, check out these possible causes:
1. Datalogger or Wiring Panel lacks 12 V power on pin 8 of CS I/O port.
The RF401 should go through its initialization with red and green LEDs
lighting (see Section 4.1.1, Indicator LEDs) when serial cable is
connected if 12 V is present on CS I/O connector (see Quick Start Table
2). If needed obtain the optional Field Power Cable (CSI Item # 14291) to
connect between datalogger 12 V output terminals and RF401 “Power”
jack to supply power to the RF401.
2. Active Interface is set wrong.
This setting should normally be “Auto Sense” unless you have a phone to
radio base station with COM220 phone modem which requires the “ME
Master” setting or you have a PakBus datalogger requiring “Datalogger
SDC” due to another M.E. peripheral present. You could set the Active
Interface to RS-232 or Datalogger Modem Enable if that is its permanent
assignment, otherwise “Auto Sense” may be better.
3. Radio has low or weak battery voltage or 12 VDC supply voltage.
The power supply battery may not be charging properly due to solar panel
orientation, poor connection, or due to a charging transformer problem.
The battery itself may have discharged too low too many times, ruining
the battery. Lead acid batteries like to be topped off.
Power supply must be able to sustain at least 9.6 V (datalogger minimum)
even during 75 mA transmitter bursts lasting only a few milliseconds.
4. Radio is lightning damaged.
Swap in a known good radio with the same settings and see if this cures
the problem. Lightning damage can occur leaving no visible indications.
A “near miss” can cause damage as well as a more direct hit with
evidence of smoke (see Appendix K, RF401/RF411 Pass/Fail Tests, for
pass/fail tests).
5. Antenna and/or cable is lightning damaged.
Swap in a known good antenna and/or cable. Hidden damage may exist.
6. Moisture is in coaxial antenna cable.
It is possible that moisture has penetrated inside the plastic sheath of the
coaxial cable. Water inside the cable can absorb RF energy and attenuate
the transmitted signal; the received signal would also be attenuated. It is
difficult to dry out the interior of a coaxial cable. Substitution of a dry
cable is recommended.
Placing a wet cable in a conventional oven at 160°F for a couple of hours
should dry it out. Shield the antenna cable against damage from radiated
heat from the oven element by placing the coiled cable on a large cookie
sheet or a sheet of aluminum foil. See Section 3.3.4, Antenna Cable
Weather Sealing, for information on weatherproofing the antenna cable.
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