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FPVCustoms Long Range Booster Kit Issues

Discussion in 'Inspire 1 Discussion' started by DSHdrone, Aug 25, 2015.

  1. DSHdrone

    Mar 31, 2015
    Likes Received:
    I recently purchase the booster/antenna kit from FPVCustoms and installed it on my Inspire 1.
    Had no issues with the installed and followed their install video exactly.
    My problem is that when I turn on everything, I get a warning message in the DJI GO app. that
    states "POOR Image reception, be cautious in long distance flights".
    I did some investigation and found that the RC Transmitter antenna signal was feeding back into
    the HCMI receiver antenna and causing this issue. I sent the following email to Paul at FPVCustoms
    and he said they have never seen this before.

    Paul: I believe I now understand how this booster setup is supposed to work.

    The RC port on the remote controller is both a transmit as well as receive channel. It is used to transmit
    Control commands to the aircraft and receive information such as parameters, GPS position,
    Speed, etc. back from the aircraft so that it can update the DJI GO app. screens.
    The HDMI port is strictly a receive only channel and there is never any transmissions
    From the remote controller to the aircraft over this port. These boosters only work because
    They are bi-directional amps.
    The blue LEDs on the booster amps only light up when it detects some type of RF carrier
    On it’s input/output SMA connectors.

    So, on the RC port, the remote controller is sending out a constant carrier and so the blue LED
    On that booster is solid Blue. I have observed this on my Spectrum analyzer and power meter.
    Going into this booster and coming from the RC port, I measure approx.. -8dbm and then measuring
    On the output of this booster, I see approx.. 20dbm which would be about right for an amp with a gain
    Of approx. 30db.

    The HDMI port is different. The booster is only receiving the RF carrier from the antenna and then gaining
    It up for the remote controller receiver. So with the aircraft OFF, this BLUE LED should not be ON as
    there is No RF carrier coming into it’s antenna. But the LED is actually flickering. I found the reason is
    coupling from the RC port transmitter feeding back into the HDMI receiver booster. If I disconnect power
    from the RC port
    Booster so it cannot transmit, then the Blue LED on the HDMI port booster goes out (which is should).
    This proves that the transmitter is feeding back into the HDMI receiver port which is causing the image
    interference message to show up on the DJI GO app.

    I am surprised that you have never seen this or had it reported from a customer. It should be happening to
    Everyone! It is inherent in the way the amplification system has been implemented.
    The way to do it properly would have been to put the HDMI boost on the aircraft rather than right next to
    RC transmitter. That way there would be no feedback into the HDMI port and it would not mess up the
    Image with interference from the RC transmitter signal.
    The only way to resolve this issue with the image using the current setup is to remove the booster from the
    HDMi channel and just run the antenna straight into the SMA connector mounted on the remote controller.
    I have done this and it seems to work better and the warning message is gone.


    Has anyone else installed this kit and are they seeing the same thing as mine with the "POOR image
    quality message? Also, are the 8 vertical bars in the HDMI channel display spiking up randomly?
    Is the blue LED on the booster amp going to the HDMI channel receiver input flickering on/off?
    Can you put your hand over the HDMI channel antenna to shield it from the transmitter antenna and
    see that the blue LED goes out on the HDMI channel booster?

    RDTech likes this.
  2. purezerg

    Mar 26, 2015
    Likes Received:
    I have yet to install mine. I got the antenna and the booster also.
    as for the 3rd antenna, I am planning to use the 2.4ghz antenna as the antenna for the 5.8ghz port and see if that will boost the range between both remotes.
  3. The Editor

    The Editor Moderator
    Staff Member

    Aug 7, 2013
    Likes Received:
    How/why would you do that considering the different wavelengths at those frequencies of 12.5cm v 5.17cm (assuming free space) - the calculations would change for a transmission line/antenna and would need to be multiplied by the velocity factor.
    Cue Nat King Cole singing "There maybe trouble ahead"........
  4. purezerg

    Mar 26, 2015
    Likes Received:
    the other port is 5.9ghz?
    i don't know. I was just wondering only. unless i get those 5.8ghz FPV type of antenna. then again. there's already 2 big ones there. any suggestions?
  5. TonyGunz

    Apr 26, 2016
    Likes Received:
    Niagara Falls, NY
    Can I call you or you call me, I posted a thread called "mod gone bad" and I think you may be able to assist me. 716 514 6240
  6. DamesNY

    Mar 25, 2015
    Likes Received:
    i installed mine and it works MIRACLES...the only time i ever get that message is when i start climbing and have forgotten to turn on the aux battery power to the rf amplifiers. so perhaps theres an issue with your aux battery or connection to the aux battery/amps?
  7. Neil sulish

    Dec 6, 2015
    Likes Received:
    im me if you are still having issues...