The MN APRS infrastructure made a big step forward this past week with the addition of AD0MI-1 as a digipeater in Askov, MN.
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| First look at AD0MI-1 coverage |
As always, you can click on that map to enlarge it.
Background
APRS coverage on I-35 has long been "spotty". After the K0YTH-11 digipeater in Hinckley left the air, a big gap was left in coverage. The RX-only gateway in Isle (W0KGW-10) provided baseline coverage for about half of that gap, and TX gateways sprung up in Pine City and North Branch (KC0KUR-10). But those gateways only lasted a few months before shutting down, and the Isle gateway has been somewhat "erratic" over the past two years. Just today, W0KGW-10 lost connection with the APRS-IS server for about two hours. It's not unusual for it to drop off the map for two weeks (or more).
Other than the RX-only gateway, there is an RX-only I-Gate (WB0VGI-1) in Harris (south of Rush City) and a TX gateway (KE0OPK-13) near Cloquet. A digipeater in Mahtowa (MHTOWA) has also provided solid coverage down to Moose Lake. All of these have been reliable.
The station
AD0MI-10 was in testing on the eastern edge of Anoka County for a couple of weeks as a TX I-Gate. It uses a Motorola Radius transceiver and a Microsat WX3in1 TNC. When it first moved to the Askov site, it failed to receive though the TX was excellent. I put AD0MI (Pete) in contact with fellow blog contributor N0ALE (James) -- who also uses the Microsat TNC -- to help track down the issue. Apparently, they were successful. The I-Gate became the AD0MI-1 digipeater.
The Askov site is excellent. It sits on high ground in Pine County, and the antenna for the digipeater is about 220 feet up from that on the tower. Unfortunately, there is no internet connection on the tower site -- though that might change in the future.
Being located close to the Wisconsin border, AD0MI-1 picks up several WI digipeaters in the northern half of the state. It also has picked up gateways and digipeaters in Brainerd, Knife River, Ely, Cloquet, and St. Cloud. It has also been picked up by a few of the metro digipeaters and gateways.
This sets up the digipeater to be a very effective hub of activity, passing traffic from the metro to both Duluth and northern Wisconsin with a single "hop" -- and vice versa, of course. Perhaps even more important, it provides access to several gateways for the local area.
Limitations
Every element of APRS infrastructure has limitations. In the case of the new Askov digi, it lacks reliable access to a TX gateway. The Isle, Duluth, and Harris I-Gates are RX-only.
Locally-generated RF messaging, bulletins, announcements, etc. can reach the APRS-IS easily. They can also reach the local area, being magnified by the wide coverage of AD0MI-1. But RF-based messaging traffic from areas outside of the digipeater's coverage will struggle to reach Pine County. It's certainly possible that the TX gateways in Cloquet, Knife River, and the metro could be relayed through the Askov digipeater, but I wouldn't call that a reliable comm link.
A TX gateway in Pine City, Duxbury, or (heaven forbid) western Wisconsin would eliminate this limitation quite nicely. This might be the perfect time for the EOC in Duxbury to slap together an HT, 1/4-wave ground-plane antenna, and an old Chromebook running Linux to create a TX APRS gateway capable of bringing RF-based messaging to Pine County. If nothing else, it would allow Pine County EMS to disseminate information and receive reports from RF stations in the local area. Conversely, Pine County EMS could run an internet connection to the County tower in Askov, and let AD0MI-1 provide that much-needed gateway coverage.
Conclusion
The RF links on APRS between northern MN and the metro have deteriorated with the passing of big digipeaters in Aitkin and Tamarack. The internet will still have a valuable role to play in linking various parts of the state until we build out more rural infrastructure. Digipeaters in Ham Lake, Milaca, and Isanti are needed for coverage to creep northward. It's also possible that mega-stations like WB0MPE-12 could return to the air in Duquette. But there's a lot that can be done on a small-scale level to improve reliability and redundancy in our network.
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