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Thread: FPV for long range shooting

  1. #1
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    Join Date
    Jan 2018
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    1

    Lightbulb FPV for long range shooting

    I am looking to build a target camera system for long distance shooting. Ideally mimicking the bullseye ammo cam.

    https://www.amazon.com/Bullseye-Ammo...tem+long+range

    These are being sold for roughly $600 and have ok reliability and ok reviews.

    The camera, transmitter, and power source all fit in an ammo can.
    Can transmit clear video feed 2km.
    Receiver can use android device as video output.
    12+ hour battery life.

    I would like to build a similar system but feel it can be done much cheaper and have better hardware. I'm not concerned about shot tracking app features. I am focused on reliable video transmission at long distance. I want good hardware.

    After some reading I have a general handle on the components required. I have listed what I have understood so far bellow.

    Camera - RMRC pro 700 or similar model
    Vtx - (1.3 GHz transmitter)
    VTx antenna - (linear directional)
    VRx- (1.3 GHz receiver)
    VRx antenna - (linear directional)
    Monitor - (possibly smart phone or tablet)
    Power source - (12v Lipo for transmitter and receiver)

    I would like any community input that can be provided on the hardware I have listed above.

    Should I be using 1.3 Ghz? I felt like it would have a good balance of penetration and distance for transmission. Most application will have clear line of sight, but there can be instances of uneven terrain and vegetation to obstruct transmission.

    I'm very confused as to the selection of antennas. I figured a linear directional would be ideal since it will be stationary.

    How many Mw should my transmitter be?

    I'm shooting to keep this project at $300 or less.

    Any and all recommendations for hardware and construction is appreciated. I am seeking knowledge and understanding. This is my first attempt at a FPV system.

    Thank you!

  2. #2
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    Feb 2016
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    141
    Cool idea! Linear antennas are subject to reflections from terrain & buildings that can cause interference, circularly polarized would likely be better. If gonna build your own, why not add pan/tilt for fine tuning view without having to run back/forth to target? Another concern is heat, even little 200w transmitters get mighty hot without any cooling from flight, there are little 1ish inch 12v PC style fans for about $5 a pair, add a heatsink and you're golden. I'd use long camera wires to keep the expensive transmitter farther away from the target, so it's less likely to get shot. If the transmitter is in a metal case, it can often be removed to help with cooling.

    With it sitting so close to the ground, range may suffer, the ground-pounder FPV guys may be better able to answer. I'm just starting my 1.3GHz adventure, so can't really help with that freq yet. A quick check at http://www.maxmyrange.com/ shows that a Singularity antenna (smallest 1.3GHz transmit antenna available) and a 3 turn helical will give ~7 miles in clear air at 200mW power, likely more than enough. That combination of directional antennas will help minimize reflections too.

  3. #3
    'avagoodweegend Heppy Ket's Avatar
    Join Date
    Jan 2014
    Location
    Adelaide, South Australia
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    326
    A shooter friend of mine uses 5.8ghz, an old video camera with a zoom lens and linear antennas with a yagi on the receiver. He transmits over 2km with a very clear picture. Monitor is a $50 7" one with no onboard receiver he bought second hand from an FPV'er (it was not bright enough for the FPV pilot). From memory the vtx was 200mw.

  4. #4
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    Dec 2014
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    96
    EZ-Wifibroadcast would be a perfect fit for that type of application. Complete setup is (depending on components chosen) around 100-120$, so if you accidently put a bullet through it, it's not going to be too costly
    This includes video transmission/reception, video recording to USB memory stick and the possibility to view the video stream over the HDMI output and on a 2nd screen via a Tablet or Smartphone connected to the RX Raspberry.


    Transmitter:
    - Raspberry Pi Zero plus camera cable (11$)
    - Raspberry Cam (15$-35$)
    - Ubiquiti Wifistation USB, Alfa 036NHA (for 2.3-2.5Ghz) or Alfa 052NH (for 5.2-5.8Ghz) (25$-45$)
    - 4GB micro sdcard (5$)


    Receiver:
    - Raspberry Pi 3 (35$)
    - 2 wifi sticks for the receiver ($10-$20)
    - 4GB micro sdcard (5$


    That setup will give you about 2km of range on the ground on 2.xGhz and about 1km on 5.xGHz with standard linear omni-antennas (that is with good line-of-sight and antennas not too low). If you need higher range or have suboptimal antenna positions (fresnel zone violated, view not 100% free, etc.) you may need to add some directional antennas.

    The nice thing about your use-case is, the transmitter is not moving like a plane or copter, so you can also use directional antennas on the transmitter which will give you lots and lots of range. Another good thing about your use-case is, you probably don't need high framerates or low-latency, so you can trade-off latency and framerate vs. quality, for example when only using 10fps, you get a lot better quality compared to 60fps.

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