This low pass filter (LPF) is a must to have if you are using a 900MHz or 1200-1300MHZ transmitters along with GPS receiver and/or 2.4GHz RC rardios.
900 MHz and 1.3GHz transmitters (TXVs) may cause undesireable interference on GPS receivers 1.575 GHz (1575MHz) mainly 900MHz TXVs, while the harmonics of the 1.2-1.3GHz TXV will most likely hit 2.4 GHz radio system.
The harmonics and spurious of the TXV signal, are strong enough to cause problems, but since they are just a small fraction of the original signal, they are weak enough to be attenuated and filtered out.
Low insertion loss
Insertion loss ~0.39dB at 910MHz
Insertion loss ~0.78dB at 1260MHz
Insertion loss ~7dB at 1585MHz
Insertion loss >32dB at 2.4GHz
50 Ohm impedance
10W Max Power
-55C to 100C Operating Temperature Range
Most installers are aware that maximizing the distance between the A/V transmitter and the RC receiver is important. But for some reason they ignore such words of wisdom, perhaps because they have a compact installation that makes this difficult to do.
Another way to reduce radiated noise from your transmitter case and wires, is to run your power and video cables multiple times around a toroidal ferrite rings as close as possible to the transmitter.