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Campbell Manufacturing R410, RF400, RF415 Transmitter Power, Cable Loss, dBm, H-3, LOSS, (dB), (ft.), LENGTH, 50 (RF415), Cable Type, (milliWatts), Outside Diameter, 100 (RF400 or RF410)

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Appendix H. Distance vs. Antenna Gain, Terrain, and Other Factors

Pr => signal power at the radio receiver in dBm

The signal power at the receiver (Pr) must exceed the receiver sensitivity

(−110 or –104 dBm) by a minimum of 6 dB for an effective link. The amount that Pr exceeds –110 dBm or –104 dBm (2.4 GHz) is the link margin.

All of these elements are known, or are easily determined, with the exception of Lp. Unfortunately, signal path loss can make the difference between a marginal link ½ mile apart, and a reliable link 10 miles apart!

Transmitter Power

Transmitter output power is often expressed in dBm, which is a decibel power rating relative to 1 milliWatt. The formula is: dBm = 10 log (Pt) with Pt expressed in milliWatts.

Transmitter Power (Pt)	dBm
(milliWatts)
1	0
10	10

50 (RF415)	17
100 (RF400 or RF410)	20
1000	30
5000	37

Cable Loss

Cable loss is a function of cable type, length, and frequency and is usually specified as attenuation (dB) per 100’ of cable. Using a low loss cable becomes very important as the cable run distances increase. Here are some typical cable types and their properties:

Cable Type	Outside Diameter	Loss (dB/100’) @ 900 MHz	Loss (dB/100’) @ 2.4 GHz
RG-58A/U	.195”	21.1
COAX RPSMA-L	.195”	11.1	18.8
RG-8	.405”	6.9
COAX NTN-L	.405”	4.5	8.1
LMR-400	.405”	3.9	6.7

*CSI stocked antenna cables are shaded.

CSI’s “COAX RPSMA-L” uses LMR-195 antenna cable. Cable loss is proportional to length as the following table illustrates.

LMR-195 Cable Loss vs. Length @ 900 MHz

LENGTH	LOSS
(ft.)	(dB)
100	11.1
50	5.6
25	2.8
10	1.1
6	0.7

H-3

Contents

RF400/RF410/RF415 Spread Spectrum Data Radio/Modem Warranty and Assistance – CAUTION – Page RF400 Series Table of Contents Introduction Quick Start Software Setup Troubleshooting D. Advanced Setup Standby Modes E. RF400 Series Port Pin Descriptions Short-Haul Modems H. Distance vs. Antenna Gain, Terrain, and Page Page RF400 Series Spread Spectrum Data Radio/Modems 1. Introduction 2. RF400 Series Specifications 3. Quick Start Step 1 – Set Up Base RF400 Step 2 – Set Up Remote RF400 Step 3 – LoggerNet/PC208W Set-up Step 4 – Connect 4. System Components 4.1 RF400 Series Data Radios 4.1.1 Indicator LEDs 4.1.2 Setup Menu 4.1.3 Networking 4.1.4Error Handling and Retries 4.1.4.2 Number of Retries 4.1.4.3 Number of Time Slots for Random Retry 4.1.4.4 Number of Bytes Transmitted before Delay 4.1.4.5 Sync Timer Setting 4.1.5 Received Signal Strength 4.2Power Supplies The RF400 series radio will sustain damage if the DC Pwr jack voltage ever exceeds Volts 4.3 Serial Cables 4.4 Antennas for the RF400 Series FCC OET Bulletin No. 63 (October 1993) approved antennas Page Page 4.5 Antenna Cables and Surge Protection 4.5.1 Antenna Cables 4.5.2 Electro-staticIssues 4.5.3Antenna Surge Protector Kit 5.Software Setup 5.1Point-to-point 5.2 Point-to-multipoint 5.3 Example Setups 5.3.1Direct PC to RF400 Series Base Station Setup Page 5.3.2Remote Station Setup Page 5.3.3 LoggerNet Configuration 5.3.4PC208W Configuration Page 6. Troubleshooting Page Page Appendix A. Part 15 FCC Compliance Warning Page Appendix B. Setup Menu B-2 B-3 B-4 Appendix C. RF400 Series Address and Address Mask Combined Network/ Radio Addresses C-2 C-3 C-4 Appendix D. Advanced Setup Standby Modes D-2 Appendix E. RF400 Series Port Pin Descriptions CS I/O FUNCTION E-2 Appendix F. Datalogger RS-232Port to RF400 Series Radio Page Appendix G. Short-HaulModems G-2 Appendix H. Distance vs. Antenna Gain, Terrain, and Other Factors Overview Link Analysis Transmitter Power Cable Loss Antenna Gain Receiver Sensitivity Path Loss Real World Distance Estimates Examples Range from ~9 to ~22 miles Range from ~14 to 30+ H-8 Appendix I. Phone to RF400 Series Page 2)AT Command Character: “-” Page Appendix J. Monitor CSAT3 via RF400 Series J-2 J-3 Page Appendix K. RF400/RF410 Pass/Fail Tests TESTING SC12 CABLE and PC COM PORT K-2 TESTING RF400/RF410s TESTING ANTENNAS K-5 TABLE K-1.900 MHz Gain Antenna Test Distances Antenna Power Ratio Distance Apart Over ¼ Wave Appendix L. RF400/RF410 Average Current Drain Calculations L-2 EXAMPLE #1 It ≈ 6.1 mA L-3 EXAMPLE #2 It ≈ 6.9 mA L-4 EXAMPLE #3 It ≈ 12.4 mA L-5 EXAMPLE #4 It ≈ 2.4 mA L-6 EXAMPLE #5 It ≈ 4.1 mA L-7 EXAMPLE #6 It ≈ 0.6 mA L-8 EXAMPLE #7 It ≈ 0.43 mA L-9 L-10 Page Campbell Scientific Companies Campbell Scientific, Inc. (CSI) Campbell Scientific Africa Pty. Ltd. (CSAf) Campbell Scientific Australia Pty. Ltd. (CSA) Campbell Scientific do Brazil Ltda. (CSB)