[App_rpt-users] Voted Simulcast Configuration Questions

[Caleb Pal]

All,

Thank you for all of the information and diagrams, it will give me a 
great place to start!

Tim, do you happen to know what older versions of Quantar FW may have 
issues? Both of our machines have 16.xx or so, and I don't believe our 
SCM's are upgradable.

Thanks,

Caleb

On 2/27/2014 0707, Tim Sawyer wrote:
> 1) See attached drawing and http://www.repeater-builder.com/motorola/quantar/q-interfacing/quantar-interfacing.html
>
> 2) Yes, tune the Quantar per service manual before interfacing the RTCM. Then you'll need to adjust the RTCM per it's instructions to set audio levels, sq diode, sq level, etc.
>
> 3) See attached drawing. The 1PPS is a BNC on the Trimble.
>
> 4) Jitter is buffered at the RTCM (TX) and at the computer (RX). The length is adjustable for both. A few hundred milliseconds if jitter is ok bit less than 20ms is ideal. More important than length, you want your path to have as consistent jitter as possible. Chan_voter has a "voter ping" command to give you an idea of your network performance.
>
> 5) We use an Intel Atom board. It's supporting 8 RTCMs with less than 20% CPU.
>   
> RTCM squelch setting should be set well above threshold... about 5 turns above threshold. Use the RTCM BEW mode. Be sure you have the latest Quantar firmware as some older versions don't have enough discriminator noise.
>
>
>
>
>
>
> --
> Tim
> :wq
>
> On Feb 26, 2014, at 11:17 PM, Caleb Pal <cleb at defcon-3.net> wrote:
>
>> Hello All,
>>
>> We are working on setting up a Voted Simulcast system on 70cm, and wanted to get ya'lls input on a few things. Excuse me for being a little new to this!
>>
>> We have two existing repeaters, both Motorola Quantars, with 4 wire Wireline cards. They are currently both on the same frequency, with different PL's to access. The Quantars have pretty diverse coverage areas, but there is definitely some overlap. I have ordered, and hope to have shortly Trimble Thunderbolts as well as RTCM's for both machines. I have a few questions about setting this all up.
>>
>> 1.) Quantar to RTCM interface and Quantar Programming: Can someone provide pinouts or diagrams for interfacing the RTCM to the Quantar? Is audio off of the 4W connector, and COR/TX via the MRTI? How is the Quantar Programmed for operation with the RTCM?
>>
>> 2.) Tuning: Is it OK to have the Quantars tuned before bringing the RTCM into the mix, or is it best to do it all on the service monitor with the RTCM controlling the Quantar? What are the important points to hit when tuning the Quantar/RTCM?
>>
>> 3.) Thunderbolt to RTCM: Is there documentation on this interface? Is it serial between the two or is there a 1 PPS signal as well?
>>
>> 4.) Latency/Jitter: What is the top end of the latency the Voting/Simulcast system can handle? We are working on getting a private VLAN over Fiber between our two sites, but until the funding for that becomes available, we will be working over the internet and a VPN. How does the system handle Jitter, and how much jitter can the system handle before things start behaving poorly?
>>
>> 5.) Processor Requirements: We currently have 2 TX/RX sites, and plan to have a 3rd in the future. Will something like a BeagleBone Black handle the load? Our alternative would be an Fit PC 2, running an 1.6GHz  Atom. Open to suggestions.
>>
>>
>> Thanks Much!
>>
>> Caleb
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