APRS update 1/9/16

  A few new APRS gateways have joined the local network recently. First, AE0RF (Justin) has got his AE0RF-10 RX-only gateway back in the game. It's already gating packets in the challenging RF environment of downtown Minneapolis. Second, AE0MT (Mike) has very recently brought a solar powered Raspberry Pi (RPi) receive-only gateway online in Coon Rapids. AE0MT-10 is providing local coverage of Hwy 10, and we'll get a better idea of its wider coverage as time goes on. Third, N0QHM (Jim) has his gateway and digipeater back on the air in Bloomington. N0QHM-1 covers a lot of the south metro on a fill-in basis, out to 35E and down to Burnsville. This is an area of relatively heavy packet traffic, and a gateway is needed there for redundancy of coverage. 

  The big N0HOY-10 digipeater in Arden Hills is currently down. This is a great example of why we need these local-coverage gateways.

  N0BVE (Don) provided a real-time test of APRS coverage recently, and it was interesting. Don drove from Minnetonka down to south-eastern MN with a 5W HT and a 5/8-wave whip, and he let me know ahead of time so that I could watch how his packets were handled. One of my concerns has been that our current network is built for higher-powered mobiles, so Don's trip with a 5W mobile station was interesting to me. 

  In town, of course, coverage was great. His HT was SmartBeaconing, so there were plenty of data points. As he got on to Hwy 52 near Inver Grove Heights, though, coverage became fairly sporadic. There's a need for an RX-only I-Gate (or even a low-power digipeater) somewhere between Inver Grove Heights and Hampton on Hwy 52. Operators with more power might have little difficulty in that area, but what we have now isn't reliable for gating packets with low power. 

  As Don approached Hampton, the W0MXW-3 digipeater in Rochester took over the bulk of Don's packets. This digipeater was over fifty miles away, and it was passing on packets from a 5W mobile! The KC0REO-10 gateway in Owatonna ended up actually gating those packets. 

  Once you get into southern Minnesota, there are a lot more digipeaters than there are gateways. If there was more traffic, I think that the three gateways for the area would really struggle. Still, there were no areas of sporadic coverage for the remainder of Don's trip.

  In Rochester, Don got off Hwy 52 and on to I-90. The two Rochester digipeaters (W0MXW-3 and WB0MPE-7) took over fully, and passed packets to N0OWT-3 in Winona. Further east, the Wisconsin digipeater N9QIP-9 and the W0NE-1 gateway were an efficient team. Even down in the river valley at Onalaska, N0EXE-3 digipeated Don's packets to W0NE-1. 

  I was impressed with this model. It wouldn't work in the metro, because the few gateways would get overloaded, but it does a fine job handling low-powered mobile packets. South of I-90, however, the terrain gets very challenging and it's doubtful coverage would be so continuous. But I'd see the priority as covering the interstate, and the APRS network probably could handle low-powered mobiles all the way to Albert Lea along the interstate. 

  The only weak point in the trip was in the south-east exurbs. I know that I've heard of operators with portable APRS radios in Eagan having trouble getting their packets gated. This seems to be "low-hanging fruit" that a RPi RX-only gateway could easily resolve.