1. 1 National Urban Search & Rescue Response System Communications Specialist Course Communications Specialist Course Skill 3 Unit 2: RF Cables and Meters

2. 2 National Urban Search & Rescue Response System Communications Specialist Course Unit Objective Upon completion of this unit, you will be able to Describe RF coaxial cables and connectors and their installation and care Test an installed transmitter, coaxial cable, and antenna with a wattmeter for proper operation

3. 3 National Urban Search & Rescue Response System Communications Specialist Course Enabling Objectives Describe RF coaxial cables and connectors Describe the installation and care of coaxial cables and connectors Describe the use of a wattmeter Test an installed transmitter, coaxial cable, and antenna with a wattmeter for proper operation

4. 4 National Urban Search & Rescue Response System Communications Specialist Course RF Coaxial Cables

5. 5 National Urban Search & Rescue Response System Communications Specialist Course Coaxial Cable Construction Center Conductor Dielectric Shield (s) Outer cover

6. 6 National Urban Search & Rescue Response System Communications Specialist Course RF Coaxial Cables Preassembled in the cache with connectors installed Cable specifications include the loss/ft in decibels (dB) The longer the cable the more power loss (Attenuation) Protect cables from damage

7. 7 National Urban Search & Rescue Response System Communications Specialist Course RF Loss 25 watt base station 0 dBno loss25 watts 3 dBx.5012.5 watts 6 dBx.256.3 watts 10 dBx.10 2.5 watts 15 dBx.032.79 watt 20 dBx.01.25 watt

8. 8 National Urban Search & Rescue Response System Communications Specialist Course Coax Cable Loss 420 Mhz RG 5810.4 dB/ 100 Ft RG 213 4.7 dB/ 100 Ft LMR400 2.6 dB/ 100 Ft

9. 9 National Urban Search & Rescue Response System Communications Specialist Course RF Connectors Must match the cable Use N type connectors when possible Keep connectors clean and dry Seal connections from weather Protect connectors from damage Have spare connectors, adapters and installation tools

10. 10 National Urban Search & Rescue Response System Communications Specialist Course RF Wattmeter

11. 11 National Urban Search & Rescue Response System Communications Specialist Course Wattmeter Set Up

12. 12 National Urban Search & Rescue Response System Communications Specialist Course Checking the RF Power Turn off the Transmitter Install the wattmeter in the Coax at the transmitter Start at 500 watts and FWD Key the transmitter Lower the range until a useable reading is on the scale – record reading de-key the transmitter

13. 13 National Urban Search & Rescue Response System Communications Specialist Course Checking the RF power (continued) Switch to REV Key the transmitter If necessary lower the range to get a useable reading on the scale Reflected power should be 10% or less than the Forward power reading

14. 14 National Urban Search & Rescue Response System Communications Specialist Course Causes of High RF Power Reflection Mismatched or damaged antenna Damaged Coax or connector Shorted Coax or connector Debris or water in coax or connectors

15. 15 National Urban Search & Rescue Response System Communications Specialist Course Review Coax Cable Construction Center conductor Dielectric Shield Outer cover

16. 16 National Urban Search & Rescue Response System Communications Specialist Course Review (continued) The longer the RF cable the more power loss 3 dB loss = 50% loss 10 dB loss = 90% loss Protect RF cables from damage

17. 17 National Urban Search & Rescue Response System Communications Specialist Course Review (continued) RF Connectors Keep clean and dry Protect from damage Seal connections from moisture

18. 18 National Urban Search & Rescue Response System Communications Specialist Course Review (continued) RF Wattmeter FWD measures RF power from transmitter to coax and antenna REV measures RF power reflected back to transmitter REV power should be less than 10% of FWD reading

19. 19 National Urban Search & Rescue Response System Communications Specialist Course Review (continued) Common causes for high reflected wattage Mismatched or damaged antenna Damaged or shorted coax or connector Debris or water in connector or coax

20. 20 National Urban Search & Rescue Response System Communications Specialist Course Unit Summary Describe RF coaxial cables and connectors Describe the installation and care of coaxial cables and connectors Describe the use of a wattmeter Test an installed transmitter, coaxial cable, and antenna with a wattmeter for proper operation

21. 21 National Urban Search & Rescue Response System Communications Specialist Course Unit Evaluation Please fill out the evaluation form for this unit