Split site 6M repeater using ASL 2.0.0

Has anyone done a split site repeater using the beta 2.0.0? Looking for tips, issues, etc.

John N4SJW Parker, CO

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Assuming you have IP networking at both sites, you could put a node (maybe on a Raspberry Pi) at each site and wire the receiver radio to one node and the transmitter to the other node. Then with connect the nodes together. You could connect in monitor mode, the transmit node monitoring the receive node.

The transmit node would be a public node and the receive node would be a private node. That’s because the receive node only needs only to connect to the transmit node but the transmit node would want to additionally connect to the AllStar network.

But if it were me I’d buy two RTCMs and connect them to one public node. RTCMs can be receive only, transmit only or both transmit and receive. I’d put the node somewhere other than at the transmit site. Perhaps at my house or on a $5/mo Vultr server.

Nothing specific to ASL Beta 2.0. Any current AllStar version could do either of the above options.

Thanks Tim. I didn’t know the RTCM was back in business, just looked at the site, worth considering.

FYI, for the Motorola CDM1250 which we will be using, you can set a channel for receive only.

John, micro-node.com came back a couple of weeks ago. RTCMs and CDMs play very nice together.

In the past I was involved with a 10m split site repeater. Of course this was in the days of RF linking so the receive site was where the club’s other repeaters and Link Communications RLC-4 controller were located (about five miles between the sites). The repeater was a pair of GE Master II mobile radios, one UHF and the other VHF low band. The UHF receiver was swapped into the VHF radio and vice versa. As the controller was located at the receive site, the auxiliary link and the 10m transmitter were ID’ed as a matter of course during normal operation.

These days I like the VoIP idea between the sites, but if I had line of sight and tower access, I would go with the usual 802.11 hardware and perhaps the AREDN firmware for the IP link between the sites. This would keep that part of it all under Part 97 rules. Of course, as Tim advises, the TX site should have access to the Internet for AllStar network access.

Either approach between the sites (private or Internet) has pros and cons.

The transmit node would be a public node and the receive node would be a private node. That’s because the receive node only needs only to connect to the transmit node but the transmit node would want to additionally connect to the AllStar network.

Why would the TX site need to access the AS network?

For access to other nodes on the AllStar network which is optional of course.

Or are you asking why the Tx vs the Rx node needs access to the Allstar network? I guess the Rx node could be the public node with network access. That might make sense depending on where the Rx or Tx is located.

I tend to think in terms of RTCMs being at multiple Rx sites with one RTCM at the Tx with the node. But that’s not your architecture.

There are lots of ways to skin this cat. You could even do it with one RTCM which could be at either end depending certain factors.

To my way of thinking (as twisted as it may be), I wouldn’t necessarily want public access to a “private” link between my split-site repeater. I suppose it’s possible he’d want to be able to link to other AS nodes to/from his 6 meter repeater however.

I was looking through the RTCM documentation last night, and if I understand, if I’m doing a split site, I’ll need a RTCM at the receiver(s) and transmitter site, and also a Raspberry Pi at the transmit site for Allstar access? That’s the part I’m a bit confused about, how do you connect the TX RTCM to the RPi?

John (long time no chat!)

For what it’s worth, have you looked at Repeater-Builders’ offerings? (unless your planning on voting?)



Your split site could be done with one RTCM and one URI. Or it could be done with 2 RTCMs. Or it could be done with 2 URIs. The only case when a RTCM is needed at the Pi is in voting and/or simulcast applications.

The RTCM connects to the Pi via ethernet. In your application you can think of the RTCM as nothing more than a sound fob at the end of a very long cable.

Yes. I used the RIM-Maxtrac on a project. Worked out great with a CDM.

Hi Ken, good to hear from you.

I’ve used the RIM boards and was building a prototype last weekend on a VHF CDM1250 but it failed (died) and not sure about the mechanical stability of the board for mountain top repeater use. We have an RA-40 board running ASL 2.0.0 into an MTR2000 on 2M and are very happy with it. So if we do a split site, that will likely be the preferred interface for now. Not thinking of voting a 6M repeater (sure wish Yaesu was making it triband HT w 6M) so that effort won’t benefit from the RTCM. I am considering a local split 2M repeater that could be voted for local HT coverage in southeast Denver metro area. That would entail the RTCM + GPS input for the future project but for now, just need to get the split site 6M working before our Squaw Mountain site gets snowed in.