13 I-Gating

APRS Article 13

September-October 2001

I-gating or ‘Getting it on the net’

By Jeff Robbins

VE3JTR (Voice Call)

VA3JTR (APRS Call)

One of the things that makes APRS so appealing, and demonstratable to the general public, is getting all that APRS data on the Internet. By logging into your choice of Internet Websites, you can view up-to-the-minute data on any Amateur Radio station on APRS. You can see current positions of mobile and base stations, you can view current weather stats from hams who have incorporated weather stations, and even follow conversations between hams chatting on APRS. This allows prospective hams to become (more or less) and active participant in APRS before they are licensed to get on the air.

APRServe was written by Steve Dimse K4HG. It is a wonder that Steve has time to write such a quality utility for APRS, as Steve is an Attending Physician at Jackson Memorial Medical Center Emergency Department in Florida. As Steve writes on his website, “Yes, I work in a place very much like what you see on the TV show ER. Of course, I'm not as good as the doctors on TV, but it's a living.”

In planning APRServe, Steve had seven items in mind for the final product:

1. The program should relay data from a local TNC onto the internet, just as the other Internet Gates (IGates) do.

2. The program should be able to connect to a list of other servers to obtain live data from other full time sites, and to interconnect with other copies of itself running in other locations.

3. There should be an echo function to allow non-permanent sources to connect to APRServe, and add their data to the stream.

4. The data coming in from the various sources should be filtered to eliminate as much redundant data as possible.

5. There should be a buffer of data to allow the immediate transmission of all known information to a newly connected client.

6. There should to be a way to remotely monitor the status of the server.

7. Local TNC data should be accessible either alone or as part of the merged stream of all data.

Steve discusses these items in detail in his DCC Paper presented at the 1997 Digital Communications Conference. The paper can be read on the net at http://www.aprs.net/aprserve.dcc.html in it’s entirety. Essentially, Steve’s software resides on servers on the Internet, and collect APRS data from participating APRS stations and Digipeaters. Now of course, these stations need an RF connection to collect data from the ether, and an Internet connection to pass the data on to APRServe. APRServe is able to share the data with other sites running APRServe, and using filters and buffers, is able to reduce duplicate data. Client sessions, such as javAPRS, can connect to APRServe and tap into the data, and present it on your screen in real time.

So as APRS/Igate stations get established, more data is entered into the Internet data pool, the more complete the Internet based map becomes. Here in the Quinte area, our representation on the Internet has been spotty at best. In order for our stations to appear on the Internet, our RF had to hop all the way into Ottawa, which required three or four hops depending on conditions and traffic. Recently, the folks in Kingston, ON have remedied that situation, and now a full time Igate is in service in Kingston. Chip Chapman, VA3KGB, made the following announcement on the Ontario APRS list about the Kingston APRSD server now being available fulltime:

Well folks, its been some time, but thanks to Mike, VE3BGP, and his XYL for letting us put the system at their QTH, and especially to George for originally setting up the Linux box, and spending time over the last couple weeks on ICQ helping troubleshoot networking through my office hook-up and then at Mike's QTH hook-up.

You may have seen the radio side (VE3KBR) the last couple of days but it was not really connecting to the Internet. As of 22:15 local Ontario time, we consider the Kingston YGK server/VE3KBR radio/internet working.

Once again my thanks to the Kingston area Amateurs who have donated time and equipment and thanks again to George N4NIV (from his warmer climate down south - something he doesn't like about our warm winters hi hi)

You should see the VE3KBR at http://www.canaprs.net/cgi-bin/locate?stn=ve3kbr (there already) or http://map.aprs.net/ve3kbr once it works its way into the system (hopefully)

CJ 'Chip' Chapman, VA3KGB

Kingston Amateur Radio Club

APRSd server and Linux newbie (help!!!)(hi hi)

As we all know, large scale projects such as these rarely are solo efforts, but rather many people cooperate to achieve the goal. Congratulations to everyone in the Kingston area who participated in the successful launch of the APRS gate for Eastern Ontario. Everyone else, in surrounding areas, appreciate your efforts, and you make APRS more valuable for all.

Following Chip’s announcement, George, N4NIV reminded us all that we can reduce our unproto path to avoid unnecessary QRM:

Just a reminder to everyone on the list. Please check your unproto settings and make sure that you are not using RELAY in any part of your unproto paths unless you are mobile. This will not only increase your ability to digi (because there may not always be a relay available) but it will also reduce the QRM significantly. Using RELAY in the uproto path of a fixed station is the major cause of QRM in APRS. The other is using to many paths.

With the Kingston IGATE up and running there should never be a reason for anyone in it's coverage area to use more then WIDE3-3, ALIAS1, ALIAS2, ALIAS3 or three non-generic digis.

It's really good to see all of you in the Kingston and surrounding areas on the map again!!

George, N4NIV

George lived here in Belleville for a brief spell, and I did have the opportunity to meet him and discuss APRS. George is currently living in Washington state, no doubt enjoying things on the other side of the continent.

Please note that when using the map.aprs.net address to locate a station, you are redirected to findu.com. While currently the redirection still works, it is possible it may disappear. In order to locate stations, use the following format, using VE3KBR as an example: http://www.findu.com/cgi-bin/find.cgi?ve3kbr

That is all for this issue, remember, let’s keep that map full, and the airwaves busy. Until next time, I’ll be seeing you, ON THE MAP!