Simulcast Optimization Techniques

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1 Simulcast Optimization Techniques Simulcast Forum XII Las Vegas, Nevada February 28, East Albert Street Portage WI Losey Boulevard South La Crosse WI Walsh Road Madison WI page 1

2 La Crosse Portage Madison page 2

3 Agenda Simulcast Optimization Technique Timing Offset Using C/I Plots Timing Offset Using Time Delay Software page 3

4 Simulcast Optimization Technique page 4

5 Simulcast Optimization Technique Suggested Test Equipment Digital Storage Oscilloscope Differential Scope Probes Monitor Receiver TIMS for Audio Generation Optimization Panel Remote Transmitter Keying Panel page 5

6 Digital Storage Scope Tektronix 3012B page 6

7 Differential Probe BK Precision page 7

8 Monitor Receiver Audio Output (speaker) Discriminator Output (for PL/CTCSS) page 8

9 Convex TIMS Test Set page 9

10 Optimization Panel Audio Output (speaker from Monitor Receiver) Discriminator Output from Monitor Receiver (for PL/CTCSS) PL/CTCSS Reference (Spectracom PL Board at Co-Located Site) Audio Injection Point for All Simulcast Transmitters page 10

11 Optimization Panel Remote Transmitter Keying page 11

12 Optimization Setting PL Monitor Receiver Discriminator Audio and Scope Use Service Monitor to Set Desired Deviation on Scope Set all Spectracom PL Levels During Same Session Requires Technician at Each Site for Spectracom PL Method Setting Audio Levels Monitor Receiver Speaker Audio and Scope (filters out PL) Use Service Monitor to Set Desired Deviation on Scope Set all levels During Same Session using Intraplex Requires Single Site Hear All Simulcast Transmitters Setting Delay Automatic for SynchroCast Sites Co-Located Site uses Stand-Alone Multiplexer Check at low (400 Hz) and high (2500 Hz) frequencies Setting PL Phase Reversal Timeout Transmitter Keying Goes Through Spectracom CTCSS Factory Default at 150 ms page 12

13 Setting PL (CTCSS) Channel 1 is reference (yellow) Channel 2 is Discriminator Audio of co-located site from the monitor receiver (blue) Set PL deviation of co-located site to desired value page 13

14 Setting PL (CTCSS) Key-up Remove Simulcast Site Check for Phase Reversal. Invert pair if necessary Key up back/forth between co-located and remote site to check PL level Set PL of remote site to match co-located site on scope page 14

15 Setting Audio: Co-located Site Channel 1 is reference (yellow) Channel 2 is filtered audio of co-located site from the monitor receiver (blue) Set transmit deviation of co-located site to desired value Reference is degrees = 0 degrees (co-located site) page 15

Setting Audio Remote Site Set transmit deviation of remote site to match co-located site on scope (Harris Mux) 1 degree of delay @ 1000 Hz = 2.

16 Setting Audio Remote Site Set transmit deviation of remote site to match co-located site on scope (Harris Mux) 1 degree of 1000 Hz = 2.78 usec/degree (= 1/1000/360) Check Delay: = 32.2 degrees degrees * 2.78 usec/degree = 89.5 usec 89.5 usec / 5.4 usec/mile = 16.7 miles (actual 16.8 miles) page 16

17 Timing Offset using C/I Plots page 17

18 Best Server page 18

19 Caledonia/Rio page 19

20 Caledonia/Rio Blue line is best estimate of equal signal strength area page 20

21 Caledonia/Rio d1 d2 Set site with less coverage to delay launch of simulcast: d1-(2*d2) 16.7 miles (2 * 5 miles) = 6.7 miles. 6.7 miles * 5.4 usec/mile = 36 usec page 21

22 Caledonia/Cambria page 22

23 Caledonia/Cambria d1 d2 Set site with less coverage to delay launch of simulcast: d1-(2*d2) 20.6 miles (2 * 7.3 miles) = 6.0 miles. 6.0 miles * 5.4 usec/mile = 32 usec page 23

24 Timing Offset using Time Delay Software page 24

25 Signal Strength Plot ComStudy 2 Software Stoplight Scale: Grey/Green Best, Yellow Marginal, Red Poor page 25

26 Geography page 26

ComStudy Software Only signals above this level will be checked for time delay - AND - - AND - Difference in timing between two signals must exceed this value to be shown.

27 ComStudy Software Only signals above this level will be checked for time delay - AND - - AND - Difference in timing between two signals must exceed this value to be shown. In this example: 40 usec = Hz 40 usec = Hz The signal strength difference between any two signals must be less than this value to be shown. Equal to a Carrier-to-Interferer ratio, FM capture effect page 27

individual site page 28 Set a bright color that is

28 ComStudy Software Set the relative time delay for an individual site in the Site Information of each individual site page 28 Set a bright color that is not used in the signal strength plots to display time delay

29 No Time Delay No Sites have any launch time offset page 29

30 With Time Delay Cambria and Rio Set to Launch with 10 usec Delay page 30

31 With Time Delay Cambria and Rio Set to Launch with 20 usec Delay page 31

32 With Time Delay Cambria and Rio Set to Launch with 30 usec Delay page 32

33 With Time Delay Cambria and Rio Set to Launch with 40 usec Delay page 33

34 With Time Delay Cambria and Rio Set to Launch with 50 usec Delay page 34

35 With Time Delay Cambria with 32 usec and Rio with 36 usec Launch Delay page 35

36 Simulcast Summary: Minimize the Variables Identical Non-Variable Backhaul Keeping Backhaul Inside Overall System Digital Licensed T1 Microwave Identical Audio Response Motorola Quantar Harris Multiplexers including co-located site Relay Keying to Eliminate Tone Keying Filters No Phase Reversal Checked During Optimization Audio Equalization Not Required Eliminating Time Delay Changes Harris SynchroCast page 36

Marquette County, Wisconsin Simulcast Paging System

Marquette County, Wisconsin Simulcast Paging System Simulcast Forum IX Las Vegas, Nevada April 7, 2005 W6587 State Road 33 Portage WI 53901 608-429-3300 800-424-1020 page 1 3470 Losey Boulevard South La