The big K0YTH-13 digipeater in Robbinsdale went off-air permanently in mid-November. Per reliable rumors, the operator N0ZRD (Gordy) lost the North Memorial Hospital site.
This changes the metro APRS landscape considerably. While my gateway (KD0TLS-4) benefited from its proximity to K0YTH-13, I've always felt that the digipeater had a questionable value to the network. K0YTH-13 allowed a lot of low-power stations to be heard far outside the metro. It fed the I-Gates in town with plenty of traffic, and had TX good enough to reach core gateways in rural areas. But there was a persistent downside to all of that.
Like the other two big digipeaters in the metro (N0HOY-10 and W0PZT-1), K0YTH-13 was a "dumb" digipeater. That is not a derogatory term; it simply means that these stations have no connection to the -IS (Internet Service) servers. This means that they re-transmit everything they hear, whether that traffic has already been gated or not. Every left turn made by every mobile in the metro is blasted across the landscape, even out to distant rural areas that find no value in that traffic. In an urban environment, powerful "dumb" digipeaters tend to generate more noise than the potential benefit they offer.
If the goal is to allow low-power stations access to the network, then the preferred solution would be small-scale gateways targeting local traffic. The next best option would be small-scale "smart" digipeaters. Three or four 5W home digipeaters, operated considerately and connected to the -IS, would offer the same benefit as one big "dumb" digi, and without any of the negative impacts on the network. This is especially true if these small-scale stations were configured for a "fill-in" purpose -- i.e. only re-transmit traffic that uses a WIDE1-1 path.
Another issue is that the metro has become a net exporter of traffic ever since the centrally-located W0YC-5 i-Gate went off-air. Once upon a time, the metro was the place that all of the digipeated traffic from the rural areas was gated. Now, nearly all of our local traffic is digipeated and off-loaded to big rural or distant gateways. We're just a noisy back-water in the big scheme of the state-wide network. Big and "dumb" digipeaters in the metro do what they were set up to do: move volumes of traffic with no regard to the destination. The metro has the gating capacity and direct coverage to handle its own local traffic, but that local traffic gets moved outside the area -- even after it's already been locally gated. Local gateways exist merely to service the big digipeaters as a minor supplement to outstate infrastructure. So, the "big reach" of the big "dumb" digipeaters in the metro becomes a liability.
On other words, while I'm not celebrating the demise of K0YTH-13, I'm not shedding any tears over it, either. Several metro (and metro-adjacent) gateways are seeing significantly expanded direct coverage now that one of the Big Three is off-air. Part of this is that we've seen a few new (and improved) gateways on the scene lately, but even old and smaller digipeaters like KF0ZH and K0LAV-8 have seen their range expand now that K0YTH-13 isn't gobbling up all of the traffic and sending it to St. Cloud. As it turns out, we have a much more robust network in the metro than even I had previously imagined.
I would concede that the absence of K0YTH-13 has created some coverage gaps in Minneapolis proper, and exacerbated existing gaps in the south metro suburbs. There is (and will always be, imo) a need for more small home gateways in the metro, if only to provide redundancy and a way to gate the traffic from the remaining two big digipeaters. But we are already seeing in a short time how the smaller gateways like WG0A-2, KF0JXO-10, WN0SAJ-10, and my own KD0TLS-4 have expanded their direct coverage to erase these chronic gaps.
So... let's take a look at what we are left with.
The current metro digipeater scene
There are several metro TX gateways that also have a digipeater function, and these are all "smart" (networked) digipeaters that don't re-transmit packets that have already been gated. Off the top of my head, I'd include WG0A-2, N0KFB-4, K0JDD-1, N9MEC, WSTP, W0ANA-15, K0FO-3, N0MQL-1 and KD0TLS-4. I'm sure there are more. Obviously, the RX-only I-Gates aren't providing any digipeater support, beyond gating digipeated traffic.
So, we already have a solid digipeater infrastructure within the metro by way of the existing hybrid gateway/digi stations. Some of these are capable of reaching distant gateways like K0VSC-1 outside of St. Cloud, KD9EJA-6 near Askov, the Faribault N0QVC-1 i-Gate, and a few gateways in Wisconsin. That's a firm foundation for low-power stations in the metro, and an adequate RF transport capability.
On top of that baseline infrastructure we have smaller, more niche "dumb" digipeaters: K0LAV-8 near White Bear Lake, KF0ZH in Shakopee, KE0RQP-1 in St. Paul, and KD0VJS near Lino Lakes. If you like digipeaters, we've got digipeaters.
Now add the Big Two to that landscape -- W0PZT-1 and N0HOY-10. Both are powerful, well-sited stations that cover the entire metro freeway loop and beyond. Both have multiple solid holds on state-wide infrastructure and reach well into Wisconsin.
Both are also subject to packet collisions, though N0HOY-10 seems less vulnerable. Packet collisions occur when two stations transmit on the simplex frequency at the same time. Both stations tend to lose out in this game. Even though most TNCs and clients are set up to avoid transmitting while the frequency is in use, that only works for traffic the individual station can hear. These wide-coverage digipeaters can hear traffic over a wide area. A mobile station in Woodbury has no idea that another station in Delano is also transmitting at that moment, but either of these mega-stations can hear both.
On a more practical level, this means that a 5w station in the metro that transmits incessantly can blank out these big digipeaters and render them more or less useless.
This also doesn't take into account the noise that these two stations generate, which impacts distant digipeaters and gateways with packet collisions. W0ZPT-1, for example, transmits an ID every 15 minutes. As if that weren't bad enough, it also transmits five objects every ten minutes. These are all DMR repeaters, and useful information such as the network and color code are not included in order to provide a religious message in that limited space. These objects are transmitted far outside the metro, into areas that these repeaters can't possibly reach. If these objects were maintained every hour, I might feel differently. But I really doubt there are masses of local operators consulting APRS every ten minutes in search of a DMR repeater. Also, this function could just as easily be served by sending these objects to the -IS network, rather than RF. By contrast, N0HOY-10 transmits an ID every 30 minutes. This seems to work out just fine, and no objects are maintained whatsoever. Bear in mind that a beacon ID's purpose is to let the network know that your station is still active. Every single packet transmitted by a digipeater is an "ID", since it includes the digipeater's callsign in the path. Both of these stations transmit traffic more than once an hour, so the network is already well aware of their existence.
Neither of these digipeaters can detect a mobile station's transmission in Alexandria, so they wipe out the local digipeater (WB0KUG-10 in this example) that can hear the big metro digipeater's ID. There's no discernable advantage to be found for anyone.
There is a valid purpose in having a metro digipeater that can reach distant infrastructure, and bring in DX traffic. I won't deny that. But... with great power comes great responsibility, and these two stations could minimize their negative impact fairly easily if they wished. Years ago,W0PZT-1 functioned as a gateway/digi. I have a hard time imagining that that HCEM doesn't have an internet connection at the EOC. If, (for whatever reason) AUXCOMM has some animus against gateways, they could always turn W0PZT-1 into a "smart" digipeater and alleviate a great deal of noise. And if the internet failed, they would have exactly what they have now. Perhaps there's also a Ubiquity-based HSMN solution to provide N0HOY-10 with an internet connection and transform it into a "smart" digipeater.
Summary
The loss of K0YTH-13 has shown how resilient and robust our metro network is. Its infrastructure is decentralized and fairly redundant, though it can always use a little supplement in a few chronic areas. It's a successful model of how a mesh of small and medium-sized infrastructure can deliver reliable, direct coverage to an urban environment -- all while being RF-linked to exurban and suburban elements of the MN APRS network.
The future is with a "small and many" model, rather than with the traditional "big and few" approach. It's a much more effective way to build a vibrant and inclusive amateur community, and also to expand the local knowledge base around packet comms in general.
