Transmitter Mounting Options

All BigRedBee transmitters come with the battery attached to the back of the board with a piece of heatshrink tubing binding the whole assembly together.  For GPS enabled transmitters, the heatshrink  also holds the GPS patch antenna in place and provides some protection.

I recommend  the transmitter be installed in the nosecone;   it is often empty and even a 54mm nosecone has plenty of space for the transmitter and antenna. It's  far away from the electronics bay which limits potential RF interference.   The GPS antenna looks at the horizon both during ascent and descent, providing adequate visibility to the GPS satellite constellation.  It's very common to see 10 or more satellites in view during all flight phases.

No complicated mounting sleds are necessary.  Roll the transmitter in a piece of fabric (nomex chute protectors work great) and secure the top and bottom with zip-ties.  This protects the transmitter and provides some  cushioning against   the high G forces experienced during launch.  Some suggest  that this method also limits the vibrations that can interfere with maintaining GPS lock while the motor is burning if hard mounted to an avionics bay sled.  Don't worry if you have a metal rod running through the center of the nosecone.  You do want to avoid carbon fiber, and metallic paint which can interfere with GPS reception.  Also, avoid black paint which can cause the temperate inside the nosecone to exceed the limits of the electronic components.

If you do choose to hard mount the transmitter to a sled, screws and standoffs can be used without removing the battery from the back of the board.  In this configuration, some have reported that the GPS antenna slides out from underneath the heatshrink due to high g-forces during launch.  The GPS antenna is 'floating' on top of the GPS module, and held in place only via the heatshrink.  Attaching the antenna to the GPS module is not advised,  and often results in damage to the metal RF shield.

For a more robust mounting solution, separate  the battery and GPS antenna from the transmitter and directly mount each individual component to an electronics bay sled.  The lithium poly battery can be re-used,  or a centralized power source can be shared.  The RF transmit antenna can be extended with an appropriate 50ohm coax cable, but the GPS antenna will needs to be mounted close to the transmitter PCB.

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