Mototrbo XPR8400 as relay

[lwadsworth]

Hello Experts. I have a very unique situation, its a client based need I have. I cannot use IP Site Connect, Capacity/Linked Capacity Plus etc...

What I need to do is have a portable radio transmit to a repeater (which from what I understand they have to be using the same freq. obviously opposites), then I need to have a 2nd repeater that receives from repeater 1, and transmits on a different freq to a control radio which collects the GPS data.

The reason for this, is I need to use the scan function to talk on an analog channel. However I am trying to create a multi site scenario, without having the radio subscriber have to change channels / zones to ensure the data keeps moving to control radio.

What I am trying to avoid doing is rendering all my equipment obsolete and switching to Kenwood. I can do what I need to in the NXDN series, however it will be a costly switch over for the short term. I apologize, if this question seems silly. I literally have tried every backdoor angle possible and have come up at a dead end everytime.

The only hold up is the analog talk channel, however it is a very important piece of what we do.

The portable radios will stay on the same digital channel at all times, and each remote site will have 2 repeaters. For Example:

Portable Radio:
RX: 153.xxx
TX: 158.xxx

Mobile Command Center:
Repeater 1 (based in mobile command center) for ARS purposes
RX: 158.xxx
TX: 153.xxx
Control Radio 1 (inside mobile command center):
RX: 153.xxx
TX: 158.xxx

Mobile repeater site:
Repeater 1: (the transmit on this repeater will be turned to 1 watt)
RX: 158.xxx
TX: 153.xxx
Repeater 2:
RX: 153.xxx
TX: 170.xxx
Control Radio 2 (inside mobile command center):
RX Only: 170.xxx

Can this work?

I have set up this scenario, and I cannot seem to get the two repeaters to talk.

Thanks in advance for your help.

 

[Bill_G]

You can do it, but it's doomed for failure. Thankfully, failure is easy to achieve.

You're depending on geographic isolation to prevent a unit in any area from hitting more than one repeater at a time. I can guarantee they will, and the result will be a mess without synchronization.

Perhaps you should clarify your goals. From what I can tell they are:
Up to seven mobile repeaters to be deployed to cover a large area
Shared communication between all users on all repeaters
Users should be able to roam at will without changing channels on their radios
GPS data will be collected at a central location

Basic IPSC using cellular modems to backhaul the connections will get you your large mobile footprint with GPS, but the users will need to change channels as you move about.

I'd like to know what Nexedge offers out of the box that Trbo doesn't that let's you build a large area network that doesn't interfere with itself.

 

[lwadsworth]

Bill, thanks a ton for the response. I know it seems ridiculous what I am trying to do. My plan was to have repeater 1 only transmit at 1 watt, so repeater 2 of the same rover would be the only one to be able to hear it.

The reason I am working this, is because the worksites we are on all utilize analog talk. Not supported by us. IF the site has a repeater the client has already supplied it, it not it is simplex truck to truck.

My goal:
1 - Be able to have a multi repeater site (expand as worksite grows)
2 - Only collect GPS data (no voice) from mobile and portable subscribers
3 - Ensure that the subscriber units do not have to change channel or zone as they move from work area to work area
4 - Analog voice utilized on the scan list at all times.

 

[Bill_G]

Well, as far as I know, Trbo GPS is only available in digital mode. So, that part of your project is a no-go if they insist on staying analog using Trbo product. OTOH, if they are using GPS from something else bolted on to whatever radio they have, and it's being sent in good old fashioned FSK, then you need to pass it as FSK, and not attempt to run it through Trbo digital. It would get totally corrupted.

 

[nje431]

You've got another problem with your setup that's a deal breaker. That's the repeater to repeater connection. Subscribers sync their timeslots to the repeater, which acts as the timing master in a system. But there is no mechanism for one repeater to be subserveant to another repeater's sync.