I will not cover step-by-step construction of the project. I got most of my ideas from (the main Tiny Trak page) This page. This is another page with some great Tiny-Trak building and set up information. I will try to give you some tips and things I learned during the project. Move all the way down the page to see updates, information and news.

I now have the system working and am using UI-View with AWG on my notebook with my hand held scanner to track from the SUV as well. You can also connect directly to the GPS from your computer and use map software that supports GPS to track from the GPS-35 at the same time you are feeding the Tiny Trak III Interface. (see note below). Note, these tips are all just for your information and should not be done unless you are ok with them. I cannot accept any responsibility for any damage or problems. I just offer these tips in hope that it will help some whom are trying to build a system like this and save them some time.

My system includes Tiny TrakIII version 1, Yaesu FT-1500M Two meter transceiver, Garmin GPS35-HVS and 1/2 wave two meter antenna.

Some Tips

1. When you build the Tiny-Trak III go ahead and add the 0.1uf capacitor On the bottom of the PC board between the base and emitter of Q1. This will decouple RF to ground preventing a potential transmitter lockup.

2. When you set TX Audio pot (middle left of PCB) to halfway point. If this doesn't do the trick then turn it fully counterclockwise. You may have to (I did) change the R5 from a 220K-ohm resistor to a 100K ohm resistor to get enough audio with this rig. At 1200 baud you can set the level by ear or use a deviation meter. Don't set it to high!

3. The TinyTrak III will suffer from RF saturation and cause problems. You many have RF getting into the TinyTrak's power cable. This can be easily fixed by putting a clip-on ferrite onto the positive wire. These ferrites are easy to come by, I ordered mine from Radio Shack but some have robbed them from a computer monitor cable and by keeping a minimum separation distance of 12 - 24 inches between them (the rig and the TinyTrak III box). You can also try to shield the box some.

If you experience strange problems the first thing I recommend is setting the radio to the lowest RF output level and separation to see if that takes care of it.

I used Radio Shack Part Number 90-7043 but I don't think the stores have these split core ferrite items in stock they may have to order them or you can order from RS on line. I used 5 of these, I put one on the power line (to the Tiny Trak III and the GPS unit, one on the audio input (from rig speaker), one on the FT-1500M control line (from the Tiny Trak II) and two on the line to the GPS (one at the Tiny Trak III box and one under the dash on the other side of the run to the GPS unit.

4. To set the calibration (you really should check it) I found that some packet software like MixW (link here) have a tuning aid that is built in and easy to use that will let you key the 1200 and 2200 Hz tones and adjust the calibration.

5. The Tiny Trak III board is very compact and the connections for the power in and the 9-pin connector are very close together. Good construction is required here to make sure none of the wires strand out and touch. I also used a 3M product I picked up at the hardware store that is a brush on insulation. I put some at each point the wire went through the board after everything was tested and working.

6. While debugging or if you just want to see what it going on it is handy to be able to see the LED lights on the board. Some have extended the leads on all the LED lights and mounted them in the lid of the case. I found that if you just drill small holes in the lid, right above each of the lights you can monitor what is going on well. You may want to consider this during the construction.

Some Other Tips

1. You can build a 'Y' type serial cable to connect the Tiny Track II, the GPS-35 and your computer. You can use this to monitor the GSP activity from your computer while you are feeding the Tiny Trak (comes in handy to debug) with software from Garmin or using a terminal prgm. The default is 4800 baud. You can also use any of the map software that supports GPS NMEA version 2.0 or later and track directly from the GPS as you are feeding the Tiny Trak III APS system with this type of cable. You can send information from the computer to the GPS-35 to change settings but the way I built the cable you cannot communicate with the Tiny Trak III (you need to use a standard serial cable for that).

You need two female and one male 9-pin plug (with hoods) and shielded wire. on the male plug connect wires to pins 5 and pin 3. On the female plug that will go to the GPS-35 connect wires to pins 5, 3, and 2. On the female plug that will go to the computer connect wires to pins 5, 3, and 2. You can set the length of the cable to what you need.

Now, connect the wire from the Tiny Trak III male plug, pin 5 to both of the wires from pin 5 on the two female connectors. Next connect the wire from pin 3 on the male plug for the Tiny Trak III to the wire from pin 3 on the plug from the GPS-35 and the wire from pin 2 on the female plug for the computer (note you are crossing pin 2 and 3 here). Then connect the wire from the plug for the GPS pin 2 to the wire from the plug for the computer pin 3 (again you are crossing pin 2 and pin 3). Tape it up well. I use a wire wound around the first layer of tape and covered by a second layer to add some support to the cable. Use your clamp on RF cores on this cable to help prevent RF problems.

2. RF can cause you problems! Once you protect your Tiny Trak III as noted above, you can still find problems. I had RF from the glass mount antenna getting inside the SUV and dumping the memory of the GPS-35 unit every once in a while then it would have to reset (3-5 mins). I tracked it down and had to change to a roof mounted antenna and all is fine now. I learned while I was doing some research that One of the most common sources for interference to the GPS unit is a CD player. They tend to be some of the noisiest devices out there, at least in the 1.5 GHz band. I would pay particular attention to keeping the power supply lines that feed a CD player away from the antenna and the power/data cable for the GPS35. Also, please make sure that the cable shield on the GPS35 is not connected to ground. It is connected to rf ground inside the GPS35 and it can cause a ground loop if you connect it at the other end of the cable. It should be trimmed off flush with the jacketing material.

3 You can use UI-View with AWG to monitor on the air activity and track from your computer in the car. You can use a separate receiver or scanner or you can get the audio from your packet transceiver. I just install a 'Y' adapter at the audio input plug on the Tiny Trak III box and feed the computer line in from there. You could also add an audio out plug into the Tiny Trak III box and parallel the connection. Using this method you will not decode your transmissions but you should be able to see your packets from the digi route you use. You can, with the cable above, track on map software directly from your GPS-35 at the same time.