FAQ

Tips and Tricks

1) Do NOT place your transmitter in a black nosecone. Temperatures in excess of 100 degrees C have been measured inside dark colored nosecones even when the temperature outside is just 26C. White is best!

2) Do NOT place your transmitter inside a carbon fiber enclosure. Carbon Fiber blocks both the transmitted RF signal and the incoming GPS signals. Plastic or fiberglass is best.

3) Do NOT use metallic paint. Problems similar to those related to carbon fiber can occur.

4) Do NOT transmit more often than once every 5 seconds. Frequent RF transmissions can affect quality of the GPS reception.

General Questions

Selection Guide:

Which BeeLine Transmitter should I choose?

There are two models of BeeLine Transmitter. Both are simple beacons that transmit a callsign via morse code and emit a periodic FM or CW pulse. The only difference between the two models is the power output. The BeeLine MP emits approx 100mw, while the standard BeeLine emits approx 16mw. The BeeLine MP will also consume the battery about 8x faster than the unamplified version using the same battery.

Which BeeLine GPS should I choose?

There are three different models of BeeLineGPS. All of them transmit the current position (latitude, longitude and altitude) which is then decoded by a remote receiver.

70cm BeeLine GPS:

This model operates on the 420-450Mhz amateur radio band, and has a power output of approx 100milli-watts. Range in the air is more than 40 miles. Designed for high power rocketry, it is powered by a single cell lithium poly battery (4.2V). It transmits data in industry standard APRS packets, a "TNC" is required to decode the data packets. See the radios section for more details. Amateur radio license required.

This device contain a MAX-7 gps module from u-blox and can store 2 1/2 hours of latitude/longitude/altitude at 1 hz.

2M High Power BeeLine GPS

This model operates on the 144 Mhz amateur radio band, and has a power output of approx 6 watts. Range in the air is more than 300 miles. This unit was designed for tracking of high altitude balloons, automobiles, and general tracking purposes.. It can by powered by 4x AA battery, a dual cell lithium poly battery (8.4V), or 12V automotive power. It transmits data in industry standard APRS packets, a "TNC" is required to decode the data packets. See the radios section for more details. Amateur radio license required.. This units can be configured with a SiRF III gps module or a Trimble Lassen IQ for high altitude applications.

900 Mhz BeeLine GPS

This model operates on a license free section of the 900 Mhz radio band, and has a power output of approx 250 milli-watts. Range in the air is about 15 miles. It is powered by a single cell lithium poly battery (4.2V). It transmits data in a propriety format. BigRedBee supplies a matching receiver with optional LCD display. This transmitter is FCC certified, and no license is required from the user.

Model	70cm BeeLine GPS (100mw)	2 Meter High Power BeeLine GPS	900 Mhz BeeLIne GPS
Frequency	420-450 Mhz (70cm amateur radio band)	140-150Mhz (2M amateur radio band)	900Mhz Spread Spectrum
Power output	100mw	6 watts	500mw
Range in the air	> 70 miles	> 300 miles	approx 6 miles
Amateur License required?	Yes	Yes	No
Receiver?	Commercially available	Commercially available	available from BigRedBee
Data storage?	Approx 8000 waypoints	Approx 8000 waypoints	Approx 8000 waypoints
Power source	3.5-6.0 V	4.0-9.0 V or 12-16V	3.5-6.0V
GPS Module	u-blox MAX 10	u-blox MAX 10	u-blox SAM 10

Are there any concerns regarding the battery?

YES: Lithium poly batteries can be destroyed if overcharged or over discharged. Always use an appropriate charger. NEVER discharge below 3 volts. LiPo batteries from BigRedBee have an integrated protection to protect against low discharge.

Why do I need an amateur (ham) radio license?
The radio spectrum used by the 2 meter and 70 cm BigRedBee transmitters is regulated by the FCC in the United States. The FCC requires that you be a licensed amateur radio operator to transmit on these frequencies. These frequencies may or may not be regulated in other countries. YOU are responsible for making you follow all applicable rules and regulations in your country.

The 900 Mhz transmitters do NOT require a license in the United States, Canada, or Australia.

What frequency should I use?
As a licensed amateur radio operator, you are free to use any frequency in the 70cm band. Please consult the ARRL band plans for recommendations and restrictions. You may want to avoid repeater inputs/outputs and the weak signal areas, especially in populated areas.

Where should I put my BigRedBee?
The BigRedBee Transmitter should be treated like any other piece of sensitive electronics. The circuit board can withstand very high G flights, but is not potted. The best place to put your transmitter is in the nosecone or a payload bay. Simply wrap in bubble wrap and jam it in! Close proximity to altimeters and other electronics should be avoided due to concerns of RF from the transmitter adversely affecting other electronics. Attaching directly to the shock cord is not recommended, unless the transmitter is enclosed in some protective container.

What about composite airframes?
Carbon Fiber and metal will block RF signals. Phenolic, cardboard, fiberglass and other composites are OK.

Can I use my own battery?
Yes. Any battery providing at least 3.2V and not more than 9V can be used to power the transmitter. The supplied lithium poly battery has a fully charged voltage of 4.25V, and should not be discharged below 3.2V

Can I use my own battery charger?
Yes, but it must be specifically designed to charge single cell
lithium polymer batteries.

Are kits available?
No. Only fully assembled boards are offered for sale.

Can the BeeLine Beacon transmit telemetry data?
No, you need a BeeLine GPS transmitter to transmit data packets.

How do I program my BeeLine Transmitter?
You need to download the BeeLine Communicator. The latest version is
available in the documentation and programming utilities section of this web-site

My PC doesn't have hyperterminal, what should I use to monitor the serial data stream?
I recommend Tera Term , others have successfully used 'putty'.

What kind of antenna should I use?.
1) Build your own: http://www.nr6ca.org/70cmyagi.html
2) Buy one, I recommend this: http://www.arrowantennas.com/arrowii/440-5ii.html
3) Or, for base operation, I have this one (not a directional yagi):
http://www.diamondantenna.net/x30a.html

Does the programming software run under Linux?
No, but one customer has reported that it worked fine using a windows emulator, WINE version 0.9.17.

BeeLine Transmitter

How big is it?
The BeeLine Transmitter (B1) is .88" wide x 1.725" long.

The BeeLine MP Transmitter (B6) is .79" wide x 1.9375" long.

Both weigh approx 6 grams without the antenna or battery.

BeeLine GPS

How big is it?

The 100mw (version A5) u-blox 70cm BRB GPS is 1.230" wide x 2.825" long.

The 850 mah battery weighs 25 grams and is approx 1.28" wide.

The original (Lassen IQ) 70cm BeeLine GPS is 1.225" wide x 2.865" long and weighs 25 grams w/out the battery.

The 2M High power GPS is 1.255" wide x 3.635" long and weighs 56 grams w/out battery or antenna

The 900 Mhz transmitter weighs 25 g without battery, and is 28mm wide x 67mm long

Sending telemetry data in the APRS comment field

The comment field can be updated in real time during normal operation to send telemetry data.  This can be done during by commenting a microcontroller to the serial interface and executing commands to modify the comment field while the device is in normal operating mode.  There TX and RX pins on the BRB transmitter are 3.3V TTL level signals.  Please use a level shifter if connecting to  device that operates at 5 volts.

BRB 2M Comment Field

The comment field, if present; is sent once every "n" packets, where "n" is set in the user interface by the "send every x" parameter.  A static comment field is set in the user interface, but can also be modified during normal operation using the following sequence.

Connect to; TX, RX and GND pins on the 5-pin header
Monitor the serial port (57600 8 N 1) , it will send a '!' character before sending the RF packet, and a #' when it is done
Send  "S<cr>"
The device will respond with "OK", and wait for the new comment field.
Send the new comment string; 31 bytes maximum, terminated with a '!'

BRB 70cm Comment Field

The comment field, if present, is sent with every packet. It can only be modified during normal operation using the following sequence.

Connect to; TX, RX and GND pins on the 5-pin header
Monitor the serial port (57600 8 N 1) , it will send a '!' character before sending the RF packet, and a #' when it is done
Send; "S<cr>"
The device will respond with "OK", and wait for the new comment field.
Send the new comment string, 31 bytes maximum, terminated with a '~>