Previously, I described how an HT on the fringe of the metro made contact with my very basic KD0TLS-7 laptop station that uses an HT with a stock duck indoors. That real-life example proved that our metro network is robust enough for virtually any operator to contact other operators across the metro. If you can set an HT in a windowsill, you have access to an extensive RF network that also can use the internet to connect to stations all over the world.
In this post, I want to describe how a modest RF station can reach a very wide area with APRS messaging. The implications for EmComm should be obvious, but it also shows how any level of operator can reach other operators far outside of the range of local repeaters using RF -- on VHF, not some 75M HF station that requires an outside dipole. The key is the network of digipeaters and gateways that other amateur operators create and maintain.
As I've said before, my gateway (KD0TLS-1) is not an impressive station. It consists of a Chinese Leixen 10W VV-898 mobile (which actually puts out about 8W on 2M) running into a monoband Comet SBB-25 mobile whip mag-mounted to my third-story balcony. The Comet whip has a gain of 4.1 dBi, and it has three Nagoya radials (RE-02) screwed on to the mag-mount -- which are mostly just "decorative" in terms of performance. I should probably note to all of those "helpful" senior hams who always seem to know what I 'really mean' that nothing I've written here is a Desperate Cry for Help or some subtle plea for 'advice'. I'm making a point, which is that KD0TLS-1 is probably below average compared to most VHF FM stations in the metro, and that most stations should be able to improve upon the results I'm about to relate. And, if you are looking for some Desperate Cry for Help in anything that I write, it will exist only in your "helpful" imagination.
This morning when I got up, I noticed that my weather radio had picked up a severe thunderstorm watch for my area. Looking at the National Weather Service (NWS) website, I saw that this watch included over a dozen counties. I saw this as an opportunity to send a local bulletin over APRS. I checked for any SkyWarn spotter activations, and found none. Next, I walked over to the Windows 10 tablet that comprises the "brains" for my KD0TLS-1 I-Gate and opened up a message dialog box using APRSIS32. The "recipient" was "BLN0LOCAL" -- a local bulletin -- and I set it to transmit this bulletin only over RF.
The text read "Severe Tstorm Watch until 2 pm for Ramsey, Hennepin Counties".
As I previously mentioned, this watch included 21 counties. I only mentioned two, as this was intended as a local bulletin.
Here is the raw packet that resulted from that RF transmission:
2022-07-23 08:34:02 CDT: KD0TLS-1>APWW11,KC9NVV-3,N0HOY-10,W0PZT-1,WIDE2*,qAR,NX0P::BLN0LOCAL:Severe Tstorm Watch until 2 pm for Ramsey, Hennepin Counties
For those of you unfamiliar with reading raw packets, I'll break it down.
This bulletin was first picked up by KC9NVV-3 -- a digipeater across the border near Osceola, WI.
KC9NVV-3 re-transmitted it, and it was picked up by the big N0HOY-10 digipeater in Arden Hills.
Next, it was re-transmitted by the big Medina digi/I-Gate W0PZT-1.
It was finally gated by the NX0P gateway near the Iowa border south of Albert Lea.
I should probably mention that this bulletin was also gated by N0KFB-1 in Mounds View, and disseminated by the internet to any -IS stations without RF capability.
Now, KC9NVV-3 feeds in to the impressive state-wide network of digipeaters in Wisconsin. This means that my bulletin was also transmitted across much of the neighboring State.
Sure enough, I even received an "ack" from KA0EZE-13 in the middle of Wisconsin.
The N0HOY-10 digipeater commonly reaches Faribault, across the metro, and into south-west MN. It also reaches into Wisconsin. And the Medina W0PZT-1 digi reaches across most of MN, except for the north-west.
Obviously, it reached Albert Lea, but there were probably many other areas that heard my bulletin due to W0PZT-1.
While it wasn't a vitally-important message, it could just as easily have been. Or, it could be a message sent to someone's cabin in either Minnesota or Wisconsin.
Locally, APRS message traffic is up substantially.
Again, this bulletin reached a huge area over RF. It wasn't sent by a 50W station with a big antenna on a tower. It was sent by a station that most senior hams would consider to be inadequate to reach many local FM repeaters.
People are starting to use APRS messaging, and those without at least APRS-IS access are missing out. My modest gateway is handling about 20 messages a day, and picking up a lot more than that.
It's not unusual for KD0TLS-1 to pick up messages from Wisconsin, Duluth, or even Canada. I can only imagine what the big gateways are seeing.
As I've said before, APRS is more than just position data. And this example I've presented shows that RF-only comms are powerful. Once you add the internet into the equation, operators from all over the world can access the metro -- and vice-versa.
Really, APRS is like a primitive form of social media. It uses IP space allocated solely to amateur radio, and it uses amateur VHF to access an RF-only network that can cover broad areas beyond what a basic 2M station can cover on its best day.
The hobby hasn't really yet made use of amateur satellites to connect different states in a 700-mile footprint. But I believe that will come in the future.
Indonesia is launching a digipeater sat this fall. Its intended purpose is to allow text comms across the far-flung islands of that country, with 4 or 5 passes a day. But it also will exist for the rest of the planet's use.
Already, AISAT-1 (an Indian "bird") exists, and the ISS often switches into digipeater mode for weeks on end.
Minnesota has not yet put itself on the map with a satellite I-Gate on 145.825 Mhz.
A few are also experimenting with HF APRS, which allows direct RF comms over an entire hemisphere. I'd be interested to hear of experiences with APRS on 40M, particularly in terms of gateways involved in this kind of operation.
Still, this leaves out approximately half of the licensed amateurs in the U.S. The promise of APRS, to me at least, has been access to any operator. Still, an HF gateway can handle messages sent from VHF stations -- even -IS stations -- if it's configured properly.
It's not very difficult for any licensed ham to make a contribution to the APRS network. In fact, it's much easier than it is to set up a repeater. Many have experimented with gateways and digipeaters. That knowledge is part of the pool, and it's readily available.
KD0TLS-1 is run by a Tech, and it's not a sophisticated or powerful example. Yet, it can reach over broad areas and help gate packets of all kinds -- messages or otherwise.
To me, KD0TLS-1 exists not to impress, but to show what is possible for anyone to do. It's not a "problem" that requires a glib 'solution'.
It is itself a solution that can be duplicated by almost anyone. And we can move forward using that solution, without "helpful" people telling us that it's not perfect. Because it's good enough to take its place in a robust network.
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