1.2/1.3 video and gps interference

[kdrcguy]

I am currently using a 5.8 500mw video tx on my quad and I would like something with more obstacle penetration power so I started looking around and decided to go for a 1.3 (maybe 1.2) ghz system. I have a 2.4 ghz radio but I might switch to dragon link soon. For now I will just boost it.

From my early research I remember that, unfortunately, 1.2 and 1.3 ghz will interfere with GPS, and I have GPS. Wiki info about GPS also confirms this (1575.42 MHz for L1 and 1227.60 MHz for L2 GPS signals).

I would like to know who is using 1.2 and 1.3 with GPS and what your setup is, what problems you have experienced, and what solutions did you come up with.

I am planning to fly short-medium range with my quad and around trees, houses, other obstacles.

Will be putting a better antennas on the equipment, like an inverted vee or something else. What would you guys recommend?

Thanks

[Adidas4275]

You just need a notch filter for 1.3ghz

You might get away with a LPF @1400mhz

You need one anyways so you don't knock someone on 2.4ghz out anyways.

Oh and in the US 1.28 is the only legal channel and it is far enough from the l1 GPS

[kdrcguy]

Thank you for your input. I have already purchased and received the 1.3g tx and rx from bevrc as well as a low pass filter. Built a cloverleaf antenna for tx and skew planar wheel antenna for the rx and the setup works great. Much better obstacle penetration and less snow and interference in the video.

GPS works fine with the 1.3g tx and the 1400 low pass filter. Running it on channel 9 which is 1.28.

Bought a diversity system as well as a second rx and patch antenna so I will post how that turns out later on.

What frequency does the commercial and civilian GPS units use?

[Adidas4275]

Glad it worked well for you

http://en.wikipedia.org/wiki/Global_Positioning_System

All satellites broadcast at the same two frequencies, 1.57542 GHz (L1 signal) and 1.2276 GHz (L2 signal). The satellite network uses a CDMA spread-spectrum technique where the low-bitrate message data is encoded with a high-rate pseudo-random (PRN) sequence that is different for each satellite. The receiver must be aware of the PRN codes for each satellite to reconstruct the actual message data. The C/A code, for civilian use, transmits data at 1.023 million chips per second, whereas the P code, for U.S. military use, transmits at 10.23 million chips per second. The actual internal reference of the satellites is 10.22999999543MHz to compensate for relativistic effects[74] [75] that make observers on Earth perceive a different time reference with respect to the transmitters in orbit.