KD0TLS: metro infrastructure status 10/30/21

 Here's a shot of the current metro gateway/digipeater arrangement: 

METRO APRS 10/30/21

All of these coverage maps can be enlarged by clicking on them.

There are a few familiar faces missing from this picture that those who follow the local APRS may be aware of:

• K0YTH-13 digipeater in Robbinsdale
• N9MEC gateway in Apple Valley 
• KB0HQD-10 RX-only gateway in Lake Elmo  

A new entrant to the field is N0KGK (Jim), a relatively new Tech running a digipeater out of his home QTH in Burnsville. It's a little unusual that this station doesn't broadcast the software it's using, but it seems to be a digi with decent coverage in a part of the metro where coverage seems to be declining. Even better, it's a using an alternating 10/30 minute interval between its ID packets. This makes it a very considerate user of the limited simplex space on 144.39 MHz 

N0KGK digi coverage 10/30/21

 I would rather have seen a TX gateway in this spot than a digipeater. We could really use even a modest TX-gateway station south of the freeway loop to expand messaging coverage. An RX-only gateway would also have been an effective addition, increasing redundancy in the Burnsville, MN area. Still, the addition of an RX-only gateway in Lakeville, Rosemount, or Farmington could very well leverage that N0KGK digi coverage to use metro TX capability to reach messaging stations serviced by south metro RX infrastructure. Conversely, an RX-only gateway Uptown or in Linden Hills would consolidate a lot of south metro suburban coverage gaps that N0KGK fails to reach.

 The loss of N9MEC seems more ephemeral, hopefully. This gateway has seen declining coverage for years. At one point, it used to reliably gate packets into Downtown Minneapolis. Now, it struggles to receive any stations south of the River. For some reason, it's had a very nice signal path to N0HOY-10 in Arden Hills, allowing a lot of local traffic to be funneled to N9MEC. It's primary strength has been its reliability, but now it's disconnecting from APRS-IS -- which makes it impossible to be an RX-only gateway. 

 KB0HQD has maintained an RX-only gateway in the east metro for years, adding reliable coverage for marathons and western WI digipeaters. Sadly, it dropped off the map back in July 2022. The K0JDD gateway in Woodbury does a fairly good job of covering that area, but we could still use another RX-only gateway in the Hudson/Stillwater/Lake Elmo area. Our border gateways handle an inordinate amount of Wisconsin digipeater traffic, and having some additional gateway capacity in that east metro fringe adds crucial redundancy. 

 I have mixed feelings about the disappearance of the K0YTH-13 digipeater in Robbinsdale. While it's presence benefits my station's coverage considerably, I have doubts as to whether adding a "dumb" digi (i.e. not connected to the internet) just adds RF noise or increases low-power stations' access to big gateways. K0YTH-13 has become less reliable over the past several years, and the metro could use an unreliable RX-only gateway more than it could use an unreliable "dumb" digi. 

K0JDD gateway coverage 10/2021

 While being located outside of the freeway loop, K0JDD-10 reaches into St. Paul quite nicely to provide direct gating coverage. It also holds down the SE portion of the metro's coverage, while providing messaging services into Wisconsin. 

K9MLS gateway coverage 10/2021

 It's nice that K9MLS has become more stable. I still question why we need another digipeater six miles away from N0HOY-10 and K0LAV-8, though. Yet, K9MLS operates on a respectful 20-minute beacon interval, and seems to be a "smart" digipeater (while also operating as a gateway, of course). This means that it's less likely to contribute "noise" to our local simplex channel. 

K0GV-10 gateway coverage

 K0GV-10 is back on the scene after being down for a few weeks. It's a two-way gateway, so it provides messaging service to the west metro area. Aside from covering I-494 quite nicely, it also provides fill-in coverage across the metro. If the western exurbs were ever to get improved digipeater coverage, K0GV-10 would be the gating element of that equation.

 Bear in mind that these coverage maps are really worst-case scenarios due to the way that aprs.fi handles the server data. Packets sent using WIDE2-1, for example, are considered suspicious by aprs.fi and are excluded. 

W0YC-5 gateway coverage

 The two big gateway/digi stations, W0YC-5 and W0PZT-1, provide an excellent baseline coverage across the metro. They also reach far outside the metro, connecting us to other parts of Minnesota and adjoining states. But, since APRS is a network, we need additional stations to provide a finer level of coverage and add redundancy to the network. 

 

 For several years, the metro APRS coverage operated on a fringe model: traffic from outside the freeway loop was funneled into the core gateway (W0YC-5) by digipeaters on the fringe of the metro. These digipeaters on the fringe would then re-broadcast metro traffic to the more far-flung exurban/rural areas. 

 

 To some extent, that's still the case. But the addition of W0PZT-1 (then known as N0AGI-1) created a second focal point that linked the metro much more tightly with digipeaters across the state to create a fairly robust RF-linked network. While there are still several parts of the state with poor coverage, there have been notable expansions that have made some rural areas "self-sufficient" in terms of APRS coverage and infrastructure. 

 

But, if you look at the digipeated (rather than directly-heard) coverage of even modest metro gateways, you will see that the metro still handles an out-sized share of traffic from rural areas of Minnesota and Wisconsin. This is less than ideal, and almost certainly can only be solved by adding additional rural gateways.