Whitman County WA Simulcast Systems. Steve Krigbaum Communication Systems Manager Whitman County

Size: px

Start display at page:

Download "Whitman County WA Simulcast Systems. Steve Krigbaum Communication Systems Manager Whitman County"

Sharleen Marsh
5 years ago
Views:

1 Whitman County WA Simulcast Systems Steve Krigbaum Communication Systems Manager Whitman County

4 Whitman County is budget limited Whitman County has 2,200 square miles and a population of only 47 thousand, most of whom are in the city of Pullman, home of the WSU Cougars. A similar sized county in Florida, with a much larger population but far easier terrain, has a radio shop of 50 people. I have a staff of three: Me, Myself and I. Two of them are worthless. The bottom line is that new sites are not going to happen in a hurry.

5 Whitman County needs simulcast The county is rich in topography, and poor in good radio sites. The eastern half of the county has three mountaintop sites that rise far above the average terrain. The western half of the county has rolling hills that alternately shadow and highlight the coverage from the quite low sites in the western half of the county. The high sites that are necessary for coverage are also excellent at generating unacceptable interference in the west half of the county.

6 Whitman County needs simulcast In the map below the fire departments traditionally had been divided into groups of repeaters on the same frequency as shown by the colors. The need to simulcast was greatest in the dark blue area. So we should simulcast eight repeaters so all responders in the dark blue can hear. 3 cells overerlay is the real solution

7 Let s simulcast. That fixes everything right? Tait TB9100 base stations GatesAir NetXpress T1 muxes with SynchroCast simulcast control VF40 wideband mux cards Microwave (TDM) between sites Spectracom GPS Master Oscillators JPS SNV 12 voters Convex Audio/PTT dist amps with centralized CTCSS generation Voice Optimizer Booster Limiter

8 Here is the gotcha Whitman County had been told that the Tait TB9100 Base Station was suitable for analog simulcast. I was fully confident in the concept, after all the TB9100 is the newer upgraded TB8100 and we all know they work. We bought pieces and parts as the budget allowed, and before the big cutover day I checked the propagation models and did very careful level setting and time delays. Cutover Day came.

9 Here is the gotcha Whitman County had been told that the Tait TB9100 Base Station was suitable for analog simulcast. I was fully confident in the concept, after all the TB9100 is the newer upgraded TB8100 and we all know they work. We bought pieces and parts as the budget allowed, and before the big cutover day I checked the propagation models and did very careful level setting and time delays. Cutover Day came. Disaster This is just awful.

10 What I learned, that you can learn from After much user suffering, and turning the system on and off, we came to understand that the model and reality did not agree except in single site capture. Finally I wanted to measure the delays to see if the microwave backhaul was having some undesired effect.

11 Test the delays one site at a time Let s measure the microwave delays on just one hop. The test receiver is at the far end of the first hop so let s just put in a copper loop and test the delay variance on the microwave from the head end. Stable, what now? Let s try modulating just one base station that is at the same site as the test receiver. The antennas have about 60 feet of vertical separation so very little added delay, RIGHT?

12 Testing with a Convex Simulcast TIMS

13 Lessons Learned TB9100 is not ideal for analog simulcast (TB8100s are). Never let a manufacturer give specifications orally. Always ask tech support before you try something different. Have a fall back plan. If at first you don t succeed, change the approach and try again.

14 The City of Pullman needs simulcast The City of Pullman provides Police, Fire and EMS response to the airport, but coverage was limited to poor from mobiles and none from portables. The remainder of the city had barely adequate coverage. Fire was covered from Webster Hall only. Police transmitted from Skyline only with a voted aux receiver at Webster Hall. A federal grant for runway realignment required radio coverage in the terminal, no excuses!

16 Hardware Implemented Motorola GTR8000 base stations GatesAir NetXpress IP muxes with SynchroCast simulcast control VF40 wideband mux cards Microwave and city owned fiber between sites Spectracom GPS Master Oscillators JPS SNV 12 voters Convex Audio/PTT dist amps with centralized CTCSS generation Voice Optimizer Booster Limiter

17 The updated Skyline Site

18 The Airport Site that caused simulcast

19 The airport is visible in the background

20 Airport Site equipment

21 The Whitcom Site is the head end for all 6 present and future simulcast systems.

22 Lessons learned Not all subscriber units are created equal. Always test the system with every flavor of subscriber unit. Simulcast has distinct advantages.

Previously that would have been a channel totally down for a week to get a tower crew and

23 This used to be the only Police transmit site The Police users never noticed this antenna issue until show and tell a month later. Previously that would have been a channel totally down for a week to get a tower crew and replacement antenna. The virtue that had formerly been resident inside that transmit antenna had been violently electro deposited onto the inside of the fiberglass.

24 Whitman County still needs simulcast In the magenta area in the center of the of the county there was an aging simulcast system using TenSr multiplexers and Quantars with TDM microwave connectivity.

25 The rest of the story The aging system was replaced in the center of the county (the magenta area) using GTR8000 base stations and T1 muxes. With some minor antenna changes, and managing user expectations regarding countywide coverage, it also is functioning happily. After some handwringing, and agreeing to bring in an outside consulting firm to check the design concepts after the previous disaster, we now have a plan for the rest of the county. We will be overlaying three new simulcast cells for both Fire and Sheriff. The Sheriff cells will be permanently patched and all voted audio will go out on each channel.

26 The rest of the story, continued The deputies will need to select the appropriate receive cell from three choices, but due to the overlap they will have plenty of margin for error. The margin for error for deputies will be reduced from 13 choices to 3. The opportunity to select the wrong repeater for dispatchers will go from 16 choices to 1. Fire and EMS agencies will change cells when they cross familiar fire district boundaries. The opportunity to select the wrong repeater for dispatchers will go from 15 choices to 3.

27 Hardware planned To be determined base stations GatesAir NetXpress IP muxes with SynchroCast simulcast control VF40 wideband mux cards Microwave between sites (Currently being upgraded to IP/MPLS packet Microwave) Spectracom GPS Master Oscillators JPS SNV 12 voters Convex Audio/PTT dist amps with centralized CTCSS generation Voice Optimizer Booster Limiter

28 The County in the near future

29 Steve Krigbaum

Project Recaps Fond du Lac County and Adams County Wisconsin Lessons Learned Steve Dubberstein President, Communications Service Inc.

www.rfstore.com Project Recaps Fond du Lac County and Adams County Wisconsin Lessons Learned Steve Dubberstein President, Inc. Simulcast Forum XV Las Vegas, Nevada March 10, 2011 305 East Albert Street