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Understanding GMRS Net Setup

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I am interested in the linked repeaters.  Could someone explain in detail how the system works?  How are these connected over the internet(do I need to be connected to a computer other than raspberry pi, is the raspberry pi wifi)?  Will the Retevis work like a normal repeater locally and also connect over the internet to another repeater in a different location hundreds of miles away?  Are there youtube videos of how this works?  Are there any limitations or disadvantages using a linked GMRS repeater? Thank you

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Your repeater works on its own just like it normally would. You transmit to it, it hears your transmission and repeats it. So local users can talk to local users.
When you attach and enable the linking bundle you can connect into a regional hub (177 for me in Alaska). Other linking users like yourself also connect to the regional hub. Anything that your repeater now hears is pushed out via the internet to the hub which distributes it to the other systems linked to it. Those other linked systems take the internet audio and transmit it out on their end for others to hear. Someone on that end can respond on their radio. Their signal goes into their repeater, to the link, to the hub, to your link, to your repeater which broadcasts it to your radio.


The Pi can be enabled to use Wifi to connect back to the internet. I have mine setup that way. Ethernet is probably more reliable. The RT97S that is available on this site is plug and play with the myGMRS net from what I understand.



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First you must have an understanding of how one repeater works. GMRS repeaters are always setup in frequency pairs. For example, they transmit on 462.675 and they receive exactly 5mhz UP. So in this case they receive YOUR transmission on 467.675. (Think of 2 radios with one receiving transmissions and the other transmitting them,) You have to set your radio up (either through software programming or through front panel offset option) so that you are on 462.675listening to the repeater BUT, when you push the transmit button you transmit on 467.675. You should physically see your radio change to 467.675 when you push transmit. There is one more thing called a PL tone. Consider it the super secret entry code. When YOU transmit (on 467.675) the repeater checks your signal for the correct PL tone. So lets say the PL tone is 141.3 Mhz you would need to have that programmed in your radio. If the repeater hears that sub audible tone then it WILL re-transmit your message on 462.675 for others to hear. If it does NOT hear the proper PL tone it will ignore your transmission and no one will hear you. That's what needs to be happening but the "how" will depend on each radio. The radios's owners manual will ALWAYS have the answers on how to accomplish this.

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  • 7 months later...
8 hours ago, Wolf1 said:

I heard the Midwest net on the way home tonight how do I get the pl tones to get on there or do I need my own repeater. I am new to this i just started connecting to local repeaters.

What repeater were you using?

You can find all the Midwest group repeaters on this site. If you go to the map click on the repeater you want the tones for and click on the get permission and file out what is needed and send it. Please give a week or two for a reply back. 

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