Print

[KD9FRQ]

What indicates a Receive station or digi-peater on APRS.fi ?

I traveled this weekend, trying to test my APRS setup and did not picked up for most
of the trip.

Part of this will be my using low power - but it was a test after all.

I also noticed that near my home, only one outbound ping was picked up by a station 10 miles
from the point it was transmitted but nothing after that.  Again, low power will be part of this.

I will be changing radios and using 50w later this week.

[WD9EWK]

What indicates a Receive station or digi-peater on APRS.fi ?

You'll probably have to dig into a particular call sign on aprs.fi to figure that out.

For example, there is a KY7K-10 receive-only APRS gateway at the Kitt Peak observatory in southern Arizona. If you see the information for that call sign:

http://aprs.fi/info/KY7K-10

there is a mention of being a receive-only gateway. Also look at the Last Path listed for that station - no real call signs, and TCPIP is in the path along with other items that don't look like normal call signs. With many mountaintop digipeaters around Arizona and neighboring states, KY7K-10 is oftentimes the gateway station for APRS packets over hundreds, if not thousands, of square miles out here.

On the map view for a station, if you click on the icon you may see a line stretching from that station to another station. This is usually a sign the station is transmitting via RF instead of going straight into the Internet, and showing you the path the last packet took from that station to a gateway.

AFAIK there is no simple way to separate the receive-only systems from others that transmit via RF on the aprs.fi web site. I don't think the site distinguishes between the two types of stations, since all of its data arrives via Internet - APRS stations on RF, Internet gateways (receive-only, as well as those that also transmit via RF), along with the apps some use on their mobile phones or tablets to show up on sites like this one.

73!

[KD9FRQ]

Thank you.

I swapped radios today and still only got picked up once only this time I was farther away from the station (found it using the green line)

Now I need to figure out how to make the track show the roads I am traveling like some others are doing.

[W0DLM]

Many receive-ony APRS stations will show as a black diamond with an "R" in it. But there is no rule about it, so they CAN be just about anything.

[WD9EWK]

I swapped radios today and still only got picked up once only this time I was farther away from the station (found it using the green line)

Now I need to figure out how to make the track show the roads I am traveling like some others are doing.

A few variables come into play for that...

1. Packet path. What are you using? I use "WIDE1-1,WIDE2-2" on my radios, which allows my packets to make up to 3 hops on the APRS network. Some areas prefer a maximum of two hops, or the path "WIDE1-1,WIDE2-1". Some radios will ask you to set the number of hops and whether or not to use "WIDE1-1", instead of having to enter the path.

2. Beacon interval. I normally beacon once per minute. Some frown on more frequent beaconing. Some radios and TNCs support Smart Beaconing, where the beacon rate varies based on your speed and direction (straight-line travel vs. lots of curves and turns). I have not used that in my travels. One packet per minute seems to be enough, provided you have a fair bit of...

3. APRS infrastructure. Not just the number of digipeaters and gateways in your area, but the location of those systems is important. When I have traveled in the "flat lands" (i.e., trips to Dayton or many other areas in the midwest and eastern US), I may see my packets picked up when going through towns and cities, but not between those places.

Here is a map of my road trip around last year's Dayton Hamvention:



This is also accessible at:

https://aprs.fi/#!mt=roadmap&z=11&ts=1495137600&te=1495483200&call=a%2FWD9EWK-9

If you zoom in on the map, there are some stretches where my APRS packets were not heard by anyone, or not heard by enough stations to allow for 3 hops to a gateway. Coverage wasn't bad on I-70 between Indianapolis (where I flew into) to Dayton, adn especially in Ohio approaching Dayton. I also had good APRS coverage around Dayton, even with so many stations squawking around the area during the Hamvention weekend. Also good coverage down toward Cincinnati when I visited the VOA Museum, up I-75 from Dayton to Toledo, and along the 401 freeway from Windsor up to and around London in Ontario. I put both of my call signs in the Status Text that my TH-D72 sent with each position packet, so I didn't have to change call signs at the Ambassador Bridge between Detroit and Windsor to stay legal on both sides of the border. Coverage wasn't good on I-75 between Toledo and Detroit, two stretches of US-23 (between Ann Arbor and Toledo, and between Toledo and Fort Wayne), and part of I-69 northeast of Indianapolis on my way back to the airport for my flight home. You can see the location of digipeaters and gateways, and when I drove near them more of my packets were being picked up.

73!

[KD9FRQ]

WD9EWK,

Thank you for sharing.  I have made some adjustments to my setting and I got picked up much more on my lunch outing today.

Power, beacon interval and infrastructure all played a part.

I will continue with the beaconing rate I have now.  I am using Wide1-1,Wide2-1.  It was the default. I will only change it when I make another longer trip.

Now to learn what I need to make a RaspberryPi a Dgipearter & Gateway and add another node to the local area.

[KB3VWG]

What indicates a Receive station or digi-peater on APRS.fi ?

The last callsign in the packet indicates the receive station. If you see qAR, it also is an I-Gate.

Callsigns with asterisks indicate devices that digipeated the packet.

[WD9EWK]

WD9EWK,

Thank you for sharing.  I have made some adjustments to my setting and I got picked up much more on my lunch outing today.

Power, beacon interval and infrastructure all played a part.

Glad that was useful. The http://aprs.fi web site is a great resource, not just to see yourself on a map. I end up downloading data from my trips, including the KMZ file for use with Google Earth, as this site only keeps data online for about 2 years. I have data from most of my trips, going back to 2010, at home.

As a comparison, you can take a look at my APRS track from a more recent trip, when I drove to southern Arizona, attended a hamfest in Sierra Vista, and visited some other spots where I worked satellites a couple of weekends ago:

https://aprs.fi/#!mt=roadmap&z=11&ts=1525442400&te=1525590000&call=a%2FWD9EWK-9

There are some gaps in coverage on some of the roads, but not nearly as big as some of those gaps from my 2017 Hamvention trip. And another trip in that area, where I crossed into New Mexico, in early March:

https://aprs.fi/#!mt=roadmap&z=13&ts=1520596800&te=1520838000&call=a%2FWD9EWK-9

Or my trip to the AMSAT Symposium in Reno last October, along with additional driving to the CA/NV border around Lake Tahoe, and a two-day road trip through northern Nevada east on I-80 to the Utah state line and then back to Reno via US-50:

https://aprs.fi/#!mt=roadmap&z=7&ts=1509022800&te=1509577200&call=a%2FWD9EWK-9

More gaps on some of the roads across northern and eastern Nevada, even with mountaintop digipeaters. That is a large area, and some areas had no coverage. I drove further north of I-80 at Winnemucca than the map shows, not much coverage on US-93 in eastern Nevada between I-80 and US-50, plus gaps on both I-80 and US-50. Not a lot out there.

I will continue with the beaconing rate I have now.  I am using Wide1-1,Wide2-1.  It was the default. I will only change it when I make another longer trip.

Now to learn what I need to make a RaspberryPi a Dgipearter & Gateway and add another node to the local area.

If I stay in the Phoenix area, I could go with WIDE1-1,WIDE2-1 and be fine with a 2-hop maximum, which is the default on the Kenwood radios I have (TH-D72, TH-D74, TM-D710G). Since I like to get out of town, and especially after seeing how packets are digipeated around Arizona, I decided to go with 3 hops all the time. I normally do APRS on the road with one of the two HTs, at 5W transmitter power into a whip on the car (trunk mount on my car, or a magnet mount on the roof or trunk of a rental car). As for setting up a digipeater and gateway, that's one way to help with the local infrastructure in your area.

Good luck, and 73!