Can you use a pair MMDVM hotspots to link repeaters without using the Brandmeister/MARCS network?

[jonwienke]

Hopefully the title is self-explanatory. I'm wondering if it's possible to set up 2 or more hotspots to form a private standalone network that isn't linked to any other network.

Hypothetical scenario: A company has 3 sites, and wants at least some radio traffic to be broadcast at all 3 sites. Can you set up a hotspot in DMR mode at each site, along with a bigger radio in Single Frequency Repeat mode, so that if a user keys up at site A, hotspot A picks up the traffic from SFR A, sends the audio to hotspots B and C via the internet, which is then relayed to the users at those sites via SFRs B and C? The key thing being complete independence and separation from MARCS and Brandmeister, because the traffic being business/commercial and some of it possibly being encrypted, and therefore not allowed on an amateur radio network.

Obviously each site would require a separate license for the frequencies used at each site. I want to find out if it's possible to do first, then figure out the correct paperwork and such if it is.

 

[RFI-EMI-GUY]

If you are talking about a commercial entity, then no, MMDVM hotspots cannot be used because they are not type accepted for Part 90.

What you are describing is a 2 slot tier 2 DMR system with IP Site Connect. MotoTrbo or Hytera type back bone. Those utilize a private network and the repeaters simply affiliate with each other over LAN or VPN/WAN. No central server is required.

You can have several levels of encryption from Basic (why bother) to AES, though Motorola is stingy about AES256 in their NA DMR because then folks woulds realize that DMR is a better deal than P25.

 

[jonwienke]

The idea here was to set up something basic without spending Motorola-type $$$. Is there anything approved in between MMVDM and MotoTRBO?

 

[popnokick]

GitHub - sharkrf/srf-ip-conn-srv: SharkRF IP Connector Protocol server

SharkRF IP Connector Protocol server. Contribute to sharkrf/srf-ip-conn-srv development by creating an account on GitHub.

github.com

 

[tweiss3]

I'm not sure if it's Part 90 acceptable, but you can use a Raspberry Pi and Pi-Star (the software that runs the hotspots) as an actual repeater controller. You don't use the MMDVM hat/RF portion, and would need two Part 90 radios that can handle digital transmissions, but then you have an actual digital repeater.

 

[RFI-EMI-GUY]

The idea here was to set up something basic without spending Motorola-type $$$. Is there anything approved in between MMVDM and MotoTRBO?

Mototrbo is not the usual Motorola cash cow. On bigger networks P25 was 6 times the cost.

And there is Hytera which makes very good product however Motorola sued the pants off of them for being too good. Then there is Maxon who make DMR but the repeater did not appear to be properly an IP network repeater. If I wanted to gamble, I would look at Hytera but get contractual support commitments.

Harris/Tait had something going, but I don't think it was tier 2 which is the sweet spot for DMR it was Tier 3 which was proprietary and costly. .

 

[RFI-EMI-GUY]

I'm not sure if it's Part 90 acceptable, but you can use a Raspberry Pi and Pi-Star (the software that runs the hotspots) as an actual repeater controller. You don't use the MMDVM hat/RF portion, and would need two Part 90 radios that can handle digital transmissions, but then you have an actual digital repeater.

Definitely not part 90. Also DMR is pretty fiddly to home brew a duplex repeater station with timing and waveform generation and demod. My hat is off to those who make it work.

 

[tweiss3]

Definitely not part 90. Also DMR is pretty fiddly to home brew a duplex repeater station with timing and waveform generation and demod. My hat is off to those who make it work.

There are a good handful around here by the same group, but they all use Moto radios and commercial amplifiers, hardline and quality duplexers.

 

[RFI-EMI-GUY]

MAXON is now claiming multisite IP connect with new repeater model

ER-9000 Series Digital/Analog Repeater – Maxon America, Inc.

maxonamerica.com

This may be worthy as they also make handhelds that are inexpensive and look to be rugged.

 

[jonwienke]

I'm not sure if it's Part 90 acceptable, but you can use a Raspberry Pi and Pi-Star (the software that runs the hotspots) as an actual repeater controller. You don't use the MMDVM hat/RF portion, and would need two Part 90 radios that can handle digital transmissions, but then you have an actual digital repeater.

The idea was to use a 578 in single-frequency repeat mode to do the heavy RF lifting, and the MMDVMs to link them together.

 

[RFI-EMI-GUY]

Check out MAXON, by the way they are eager to dole out dealerships.

 

[krokus]

What about remote the mobile radios back to a central point, and use a local interface?

https://www.remoterig.com/wp/?page_id=634

 

[kb9mwr]

Hotspots use the underlying MMDVM code written by Jonathan Naylor, G4KLX and comes with this license:

"This software is licenced under the GPL v2 and is intended for amateur and educational use only. Use of this software for commercial purposes is strictly forbidden."

That aside, as for operating it on frequencies outside the ham ranges, that might be permitted as its basically a Part 15 device, but that really depends on its output power/fiend strength.

 

[jonwienke]

OK, here's another scenario. I have a buddy who lives outside of simplex range. I want to set up a hotspot at my place and one at his, and be able to rag-chew with him on low power without spamming the MARC/Brandmeister networks or any public repeaters. Is that possible?

 

[tweiss3]

OK, here's another scenario. I have a buddy who lives outside of simplex range. I want to set up a hotspot at my place and one at his, and be able to rag-chew with him on low power without spamming the MARC/Brandmeister networks or any public repeaters. Is that possible?

Yes, you still set it up on brandmeister, but you can set a private call to only him:

 

[jonwienke]

I get how to configure the radios. I'm looking to configure the hotspots to talk directly to each other without using Brandmeister or MARC, knowing the IP address fo each hotspot.

I can do the network setup to make sure they both are publicly accessible as needed. But I want to know if there's any hotspot firmware version or configuration that supports a direct connection to another hotspot.

 

[tweiss3]

I get how to configure the radios. I'm looking to configure the hotspots to talk directly to each other without using Brandmeister or MARC.

You have to have something route the traffic. You could build your own DMR system for just your two hotspots, but if you are looking to only ragchew with a buddy, you are probably better off building a pair of simplex Allstar nodes (on hamvoip image). I have a SHARI PihatU that I built from Allstar – Ham Radio Projects . That will let you link each node together and use any analog HT to talk. I built mine on a Pi4, and it is nice for around the house or traveling out of state to get back to the local repeaters.

EDIT: I found this on how to build your own DMR server and connect a MMDVM hotspot to it Make your own DMR server

 

[popnokick]

So the SharkRF IP Connector Protocol server will not work?

 

[jonwienke]

A link between destination IP address and talkgroup would suffice for routing; all I want to do is pair two hotspots through the internet. If I could link 3-4 hotspots by assigning a separate talkgroup to each hotspot, that would be a bonus, but the goal is to do so with just an internet connection for each hotspot, without using anyone else's servers or infrastructure (other than the internet itself) to do so. Example:

• Hotspot 1 is assigned public IP address A and talkgroup 1000.
• Hotspot 2 is assigned public IP address B and talkgroup 2000.
• Hotspot 3 is assigned public IP address C and talkgroup 3000.

If hotspot 1 hears a keyup on talkgroup 2000, it forwards the traffic to IP address B, where it is rebroadcast by hotspot 2. Traffic on talkgroup 1000 is not forwarded anywhere. Traffic on TG 3000 is forwarded to IP address C and rebroadcast by hotspot 3, etc.

If the SharkRF server thing does that, that's exactly what I'm looking for. Can that be installed on a Pi4?

 

[popnokick]

The SharkRF IP Protocol Connector requires an OpenSPOT hotspot on each end of the Internet link between the sites. Reading the docs for it and it appears to do what you’re looking for.