[App_rpt-users] Simulcasting with RTCM/voter

[Joe Leikhim]

Garry C. Hess invented the delay spread calculation described in TSB-88. 
Modern propagation prediction software used by Harris and Motorola 
employ this method along with monte carlo simulation to depict TDI 
regions in multiple site simulcast. Regarding a specific acceptable TDI 
value,  the results are affected by number of overlapping signals three 
or more require tightening up the delay spread. Also narrow band signals 
are more susceptible, have worse (higher) capture ratios.


On 3/14/2017 5:55 PM, Hayden Honeywood wrote:
> Really interesting thread so far.
> Tim I was getting those figures from an article I read here -
> http://urgentcomm.com/networks_and_systems/mag/designing_simulcast_networks_1101
>
> "Analog FM systems on 25 kHz channels typically can withstand two 
> relatively strong, equal amplitude signals with up to 150 microseconds 
> relative delay before speech is unintelligible, according to Garry C. 
> Hess in /Land-Mobile Radio System Engineering"/
>
> I have used radio mobile quite a lot. It might be time to ascertain my 
> coverage. The only gripe I have with Radio Mobile is that it 
> overestimates at low band VHF by default. UHF coverages are pretty 
> accurate in my opinion. I've also used Splat, and still use Splat to 
> overlay onto Google Earth.
>
> Do you change the strong signal margin on one site in Radio Mobile to 
> 0dB/20dB for the 10dB difference, then plot the two together?
>
> Hayden
>
>
> /
> /
>
>
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-- 
Joe Leikhim


Leikhim and Associates

Communications Consultants

Oviedo, Florida

JLeikhim at Leikhim.com

407-982-0446

WWW.LEIKHIM.COM

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