This particular antenna supplied with the FF unit is from Aero Antenna Technology and is rated from -55C to 85c (185F).
One thing many folks may not be aware of is that GPS antennas are "active" antennas which mean they contain a built in amplifier which is powered from the center conductor of the coax. Different antennas have different input voltages, gains and associated amplifier specs which for the most part makes "sharing" them with other GPS units impossible.
More info from the install manual:
2.12 GPS ANTENNA INSTALLATION
The antenna should be installed according to the manufacturer’s instructions.
Selecting appropriate GPS antenna locations is critical to the proper performance of the FDL-978-XVR/RX. The following considerations should be taken into account when selecting the Antenna location.
Shadowing by aircraft structure (and in some cases by rotorcraft blades) can adversely affect operation of the GNSS equipment.
1. Typically, a GNSS antenna is located forward or aft of the wings on top of the fuselage.
2. GNSS antennas must be installed to provide the widest, unobstructed view of GNSS satellites.
3. Antenna placement on the airframe should be optimized to ensure the sensor can take full advantage of a 5 degree mask angle. This includes consideration of antenna location with respect to blockage from all aircraft components at typical level cruising attitude, as well as minimizing the effects of aircraft shadowing during typical maneuvers.
4. The antenna should be separated as much as practical from transmitting antennas. For small aircraft, the antenna also should be separated as much as practical from the windscreen to prevent case-to-antenna coupling.
5. For installations on rotorcraft, the effects of the rotor blades on antenna performance should be considered. This may require additional equipment functional flight evaluation or analytical evaluation to confirm the suitability of antenna location.
6. For multiple-sensor installations, the installer should reduce the likelihood that a single lightning strike affects all the sensors.