BigRedBee 70cm GPS

Once in a blue moon a product comes along which just plain works and exceeds expectations. The BigRedBee 70cm GPS rocket tracking device transmitter is one of these.

The BigRedBee transmits its GPS coordinates every few seconds (configurable) at 100mW (configurable) on any of the 70cm HAM radio carriers (configurable). The GPS coordinates are transmitted using standard APRS packet formats, so any HAM radio or TNC can receive and decode the information.

In addition to transmitting its GPS coordinates, the BigRedBee will store GPS data, at a much higher sampling rate, in internal memory. Using the supplied cables and software, the internal memory can be uploaded to a PC and plotted using GoogleEarth.

The BigRedBee package includes a Lithium poly battery, software to configure the device using a PC, and all required cabling and drivers. The BigRedBee is ready to use out-of-the-box.

Parts of the system

The BigRedBee is 1.25" wide x 2.9" tall with a semi-rigid yellow antenna extending another 7.25". With battery and antenna, the device weights slightly less than 2oz. The Garmin eTrex GPS integrates seamlessly with the Kenwood HT. The Antenna is a 7 element Yagi from Arrow Antenna. I bought the split boom (comes apart into two pieces). I'm concerned the 7 element antenna will be unwieldy in the Midwest when the corn starts to grow. I think half the boom will make a nice compact Yagi. The Arrow antenna also supports 2 meter HAM frequencies by attaching a different set of purple cross beams, not shown. Of course for close-in work the standard Rubber Duckie antenna will be more than adequate.

Configuring the BigRedBee

The BigRedBee comes with a small daughter board and USB cable. The USB interface provides both PC based configuration as well as a charger for the attached battery. Even though the same daughter board is used for configuratoin and charging, the physcial connections are different, so configuration and charging cannot be done at the same time. No big deal, honestly.

	PC Configuration via USB cable enlarge
	Battery charge via USB cable enlarge

The software is self explanatory.

Using the BigRedBee with a Kenwood receiver

Using the BigRedBee is as simple as turning-on the BigRedBee, connecting the eTrex and Kenwood together, and waiting for the GPSes to acquire the satellites. For me, it worked first try. Once everything is running, the information below displays.

	Local GPS coordinates read from connected Garmin eTrex
	Altitude transmitted by the BigRedBee
	Remote GPS coordinates transmitted by the BigRedBee
	Distance and heading from the Garmin to the BigRedBee. The BRB is sitting a few feet straight north of my location.
	If the BigRedBee is moving, the heading and speed are displayed. The BRB is stationary in this photo.

Google maps

The BigRedBee stores high frequency GPS position in its internal memory. Later the memory can be transferred to a PC and seamlessly imported into GoogleEarth, which can display a 3D plot.

Since I only walked around the block near my house, the GoogleEarth plot is boring, but it serves as an example. Although the neighborhood is "heavily wooded," the BigRedBee maintained satellite lock.

With the BigRedBee sitting on the ground, I was able to receive its signal from 1 mile away (and probably farther) using the 7 element Yagi from Arrow Antenna. Again, the neighborhood is not RF friendly. I'm sure the range of the BigRedBee will be excellent in the air, line-of-sight.

Project

My first project using the BigRedBee is a minimum diameter M rocket. The BigRedBee will sit inside a hollow cedar nosecone with a metal tip. I hope to fly the BigRedBee in a minimum diameter O late in the year.

Project updates soon

Links