Starting from scratch with mobile APRS system - could use some help

[KD8GME]

Hey everyone, I've been doing a ton of research and am getting a little overwhelmed.  Can you help me out with a bare-bones APRS setup from scratch?  Since I am just starting to play around, I want something that works inexpensively, just to see if APRS is something I'm interested in and then might upgrade to the whole nine yards in the future.  I am also interested in keeping this a small(ish) self-contained unit I can take from the car and strap on to my motorcycle... if possible.

I prefer something where I can see other stations/info on the GPS screen (I've read the Nuvi350 is a good inexpensive option for that?), but I do have an older Garmin 60C that I could use to get started if needed. But I've read that unit is not ideal.

So I need info on a full inexpensive system.  If I got a Nuvi350, what data cable do I need?  What is a reliable older HT transceiver I can pick up used?  What else do I need to know to get started?  What do you recommend?  All opinions are welcome.

Thanks.

[KB9BPF]

As when learning anything new that has some complexity, you'll have to learn to walk before you can run. Focus on a simple setup and learn the abilities / limitations of APRS before going for the motorcycle APRS thing.

Simple / cheap: something like a Byonics TinyTrack 4 and a simple, inexpensive, possibly used, HT would be a good start. Something like an old Yaesu FT-209RH or Alinco DJ-196 (I think that's the 2M model of that series?) would work great. If you're not up to making the audio/PTT cable, Byonics sells them ready-made. The TT4 is quite small but does not have it's own power source like an HT. For a GPS I used an old Garmin Foretrex 101 wrist GPS with a simple 3-conductor phone plug serial output. I don't know the Garmin 60C but if it's got a serial output you'll be able to connect it to the TinyTrack 4.  Byonics (among others) also sells a very nice 'hockey puck' GPS receiver and ready-made cables for different applications.  I've used such a setup with a laptop running UI-View and Precision mapping software.

Instead of a TinyTrack 4, which is a specialized TNC, an old TNC from MFJ, AEA, PacComm, or Kantronics, even if it doesn't have the newest firmware that supports APRS, can be used in KISS mode with suitable software on a computer, such as UI-View or APRS-IS32. If you don't already have a TNC you can probably locate one real cheap if you ask around.

Over time I've accumulated different APRS hardware, including a used Nuvi 350. You'll need a special cable for this, one which not only converts USB to serial data but also converts Garmin's propriety data format to standard NMEA. Fortunately such an animal does exist, thanks to Argent Data Systems. It adds $60 or so to your project, on top of the $70 or so you'll pay for a good, clean used Nuvi 350. Personally, after using a newer Nuvi with a larger screen (but no APRS compatibility) I'm pretty spoiled: an awful lot of the '350's smallish screen gets used up by 'buttons' leaving the area for map display to be desired. When zoomed in enough to get city street resolution, you're not going to see many APRS spots unless they are within several blocks. In order to see most received APRS spots you'll have to be zoomed out pretty far so your small screen covers many square miles. (I can't imagine fiddling with zoom settings on a GPS while riding a motorcycle is very safe. But you can't do a laptop on a motorcycle either...)

For a motorcycle I'd think that a Kenwood TH-D72A HT with GPS receiver and APRS TNC built-in would be the cat's meow, but you won't have a map screen to look at unless you disable the internal GPS and use a Nuvi350/GTRANS-KW cable (in which case you could use a used TH-D7 HT with APRS TNC but no internal GPS).  Those Kenwood APRS-ready HTs aren't cheap but they're compact and powerful APRS tools. They aren't very hard to get set up though!

You asked for a simple answer but I'm afraid it's tough to do that since there are so many factors involved.

73 and good luck,
Brad KB9BPF

[KD8GME]

Thanks for the detailed response, Brad.  I really appreciate it.

I should've been clearer in my original post.  I'd prefer to have a usable screen where I can see other stations while in the car, but that's not important to me on the motorcycle as (you're right) I'll be a little too busy to be studying that while riding on two wheels.  I was thinking I could hopefully have the best of both worlds with some detail in the car, and then just throw everything in a bag and attach it to the rear seat or something to be used solely for the wife to track me while on two wheels.

Please keep the advice and specific reccomendations of makes/models of equipment coming.  I appreciate it.

[N5TWB]

@KB9BPF --

Excellent primer and guide to basic APRS. Would you care to expand your thoughts by adding parameters such as monitoring/mapping beacons and digis direct in a mobile setting while keeping the costs down, especially as regards the actual computer/monitor and mapping software? It's easy to spend multi-bucks for a high-end solution but I'm looking for a low wallet impact method that could be implemented for use by ARES when Internet access is not reliable.

Thanks for your thoughts...

Bart  N5TWB

[K7RBW]

I think the simplest way to get started would be an Argent Data Systems Tracker 2 and a Nuvi 350 connected to the radio of your choice. I would go for a mobile rig over a handheld because for consistent "pings" while on the road, you need mobile power. (BTDT) You can get multiple interface cables for the Tracker 2 to work with a variety of radios. With the Nuvi 350, you get the display and the GPS all in one, but the previous poster is correct, it's not exactly state-of-the-art anymore.

If you want to just dip your toe in the water, you can hook your computer to your radio and use agwpe on your computer to decode the packets. That should cost about $0. Also, there are some APRS programs that run on the PC and Linux which are free as well. That's a good way to try it out without spending any money. You can at least get the RF end of things working (assuming you have a radio, of course).

[N5TWB]

@K7RBW -

Thanks for the suggestions. Quick check of web info shows your suggestion to be worthy of further research, perhaps involving my wallet. I thought I had Argent bookmarked at one time but I can't recall why they weren't still in my bookmarks.

73 and a good day to you!


Bart  N5TWB

[KB9BPF]

To see APRS stations on a screen while mobiling, I found the Nuvi 350 screen to be way too small. I was much more satisfied using UI-View with Precision Mapping on a laptop sitting on the passenger side floor. (Hey! You're not going to be trying to poke around on the keyboard while you're driving, are you!) The screen is big enough to display several square miles at once and not be cluttered by the received APRS station flags.

In areas where APRS digis are not very close together you'll need a decent mobile rig and antenna, but in a city where APRS has a denser infrastructure an HT, especially if hooked to an external antenna, will work OK. And that's where you're going to find a good display of APRS stations useful, where it is more common and you'll have activity to see. Out in the sticks where the next APRS station is 10 or 20 miles away, what's the use of going to all the trouble, IMHO.

One other point: don't underestimate the usefulness of a non-graphic display. Using just the bearing/distance from my own location, and the course/speed from the other station, as displayed on the TM-D710A in my car, I can do a decent job of figuring out where the other station is and what they are doing. It takes knowledge of the area and the other station's habits, though.

When I'm doing routine driving I find the GPS map display to be distracting, which can lead to fatigue. (Distraction and fatigue is an unsafe combination!) Once the novelty wore off I stopped using the map GPS except non-routine traveling. The TM-D710A has a dedicated hockey-puck GPS RX attached so the map GPS, a newer Nuvi with larger display, is not needed for APRS and remains stowed when not in use.

73, and be safe while you're having fun,
Brad KB9BPF

[W5LZ]

I've found that I would rather use a laptop and receiver for APRS in the car.  I do other things that just keeping track of where I am, so the larger screen and APRS program features come in handy.  Not to mention other things you can do on that laptop the situation allowing.  That sort of thing wouldn't exactly be practical on a bike, but then I'm not on a bike.
There are a number of APRS programs, surely one of them would fit your needs.
 - 'Doc