12 Bits and Pieces from the Emailbag

APRS Article 12

July-August 2001

Bits and Pieces from the (E)Mailbag

By Jeff Robbins

VE3JTR (Voice Call)

VA3JTR (APRS Call)

UI-View is certainly generating a following. Well before the last issue hit the stands, I was inundated with email requesting an article on the subject. Clinton VE7KNL put it best in his email:

Hi Jeff. I’ve been following your articles in RAC, and it’s good to see someone writing about APRS. I’ve been trying to get hams in my area interested in APRS for 2 or 3 years now. So far, a lot of “yea I want to play with it one day, but..” you know the rest. Anyways, I think I may have found a partial solution, and it has a hams favorite word in it .. FREE!

Well Clinton, it isn’t just hams that like that word, but it definitely helps when you can download a fully functional version of the program to use before you buy. If you haven’t yet, take Clinton’s advice and check out UI-View. You won’t be disappointed.

Ewan VA3ECC writes:

OM Jeff, Thanks for the articles in the RAC Mag on APRS. I am trying to find some maps for UI-View for GTA/SWO on Ont. Any pointers for me please???

How about it folks, anyone in the Greater Toronto Area creating UI-View maps? Let me know so I can pass the information on the Ewan.

Next up is my very best friend, Ken VA3DDB. When Ken decided he wanted to establish an APRS presence in Brantford, ON, he secured an excellent location atop St. Joseph’s Hospital in the east end of town. Ken called me to prescribe the best software choice for his use. Our discussion determined that UI-View would be the best alternative for his needs:

Jeff! Hey, got the Digi installed at St. Joes. It’s working great. A little config here and there required. Everything is battery backed-up and on an emergency generator. VA3DDB-10 is the Digi. VA3DDB-13 is the mobile and of course, VA3DDB-1 is the QTH. The Digi is relaying to VE3KSR in Kitchener as I have not run the network cable to the computer yet for Internet access. When I do, it can logon to the APRS server and turn on the Igate.

Ken’s digipeater doesn’t even use a TNC! He is using a SoundBlaster card and the AGWPE software engine to simulate a TNC. Ken has since gone on to get that Internet connection up, and has been feeding APRS data into the Internet. He has also done something even more important; he got Brantford on the map! I plan to attend the Brantford ARC hamfest in August, so I hope I will be able to see lots of activity by then!

Bill VE3YR writes:

Very much enjoyed all your articles on APRS, and have downloaded WinAPRS. Now I need some maps for my local areas. You mentioned in one article that you could download from MapBlast, or from your website. Have you published any material on that subject, or can I go to a website? Thanks for your very good series of articles. I used to write articles on VIC20 software just to show you how old I am.

Bill, you can’t be that old, cause I used to use a VIC20 in school. I can even go a little further back to the old Commodore PET with the green monitor and tape drive. I still have a fully functional Commodore 64 in the basement with all the accessories. Many years ago, I managed to build a repeater controller and I wrote all the software for it on the 64. This was my first project that made that connection between software and hardware. Up until then, they were always separate entities in my projects. Anyhow, enough reminiscing and back to your question. My webpage is a good place to start looking for maps for your home area. If you want to create your own maps using MapBlast or any such other map repository, read the documentation for your choice of APRS software for details of how to create new maps.

Steve from across the pond asks:

Hi. I would like to build a device that can track people within a very local area. How accurate is APRS? What is its resolution? Could it be used for tracking personnel on a campus? If not, can you suggest any other technologies for doing this?

I responded with some details on GPS accuracy.

Jeff thanks for the response. Do you think it feasible to take the output from a TNC and somehow enter this as a co-ordinate into an off-the shelf GPS unit. The GPS unit could then be used for tracking the mobile TNC?

Several articles back, I mentioned that the APRS working group has allowed for incoming Waypoint information to the GPS using the ‘GPWPL’ NMEA sentence. I am guessing that this is possible. Information from the TNC could be ported into the GPS and presented on the screen as a Waypoint. I suggested this method as a solution for the Kenwood D7A lacking maps, but in that case the D7A is capable of converting other NMEA sentences to the WPL and sending it to the GPS.

Quoting page 64 of the D7A owner’s manual:

When APRS data is received with a GPS receiver connected, included position data is sent to the receiver; the NMEA-0183($GPWPL) format is used. This data is registered in the WaypointList of the receiver; the right 6 digits of the call sign is used as a name (ex. for KJ6HC-3, J6HC-3).

I don’t know if any other TNC firmware out there has this capability built in. Perhaps this is something on the drawing board for future TNC firmware revisions.

I have saved the best for last. I understand APRS has been used on the VBX balloon experiments out in the west, but over in Milano, Italy, they are doing something slightly different.

Cara writes:

I am currently in my final year of an Aeronautical Engineering Degree at the University of Glasgow in Scotland, and I have come to the part in my course where I do a related project. I have come to the Politecnico di Milano to undertake a project here. I have been assigned work, which involves APRS – something I have never been involved with before. The University has built an ultra light aircraft and have been flight-testing it. They now wish to fit the aircraft with APRS and that is where I come in. I have just started researching the topic and have found the Internet very useful – your TCA articles were amongst the first material that I read.

So now APRS is being used to track University aircraft during flight tests! Wow, it is absolutely amazing how APRS can creep into everyday life. Being able to accurately track the position of aircraft, balloons, ARES vehicles, you name it, only makes experiments more fun.

It’s kind of like that commercial on television: APRS DOESN’T MAKE YOUR EXPERIMENTS WORK, APRS MAKES YOUR EXPERIMENTS WORK BETTER!