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Legality Of Antenna Boosters

Discussion in 'Pro/Adv Discussion' started by lil boss, Oct 10, 2016.

  1. lil boss

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    Hi All,
    I'm doing some research into more range for my drone, and I read somewhere that antenna amplifiers are illegal to use in the frequencies which we use for our drones. Does anyone know if this is true ??
     
  2. N017RW

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    Yes, it is illegal to modify FCC Part 15 class equipment. This includes (just) replacing antennas.
    This is why the controllers are not sold with SMA or other common/standard antenna or RF connectors.
    Windsurfers or other reflectors are likely an allowable mod though I'm not sure of the specifics.

    Amateur licenses allow increasing ERP in some cases.
     
  3. Richard R

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    Amateur license wont help. Not operating in a ham band.
     
  4. NRJ

    NRJ

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    Do you have a source for your statement? I would love to read it. Thanks.
     
  5. N017RW

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    Yes. FCC Part-15.
     
  6. NRJ

    NRJ

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    Since you are already (I'm supposing) familiar with FCC Part-15, can you provide a link to the particular Part of Part-15 that you are referring to? I look at the page and it has many facets to it and I am only interested in the part where you say that it is illegal to change antenna's. Thanks if you can provide a link.
     
  7. montelatici

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  8. NRJ

    NRJ

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    Thanks for the link. The page you gave me only pertains to structures and their antenna's. I didn't see anything pertaining to drones or adding or changing antenna's on drones. Below their explanation of Structures.

    What are Antenna Structures?

    The FCC Rules specifically define the term "antenna structures" as “The radiating and/or receive system, its supporting structures
    [​IMG]
    and any appurtenances mounted thereon." In practical terms, an antenna structure could be a free standing structure, built specifically to support or act as an antenna, or it could be a structure mounted on some other man-made object (such as a building or bridge). In the latter case, the structure must be registered with the FCC, not the building or bridge. Objects such as buildings, observation towers, bridges, windmills, and water towers that do not have an antenna mounted on them are not antenna structures and should not be registered. Keep in mind that the FCC only has jurisdiction over antenna structures, and thus, other objects that do not house antennas are not required to be registered with the FCC -- regardless of their location or height.
     
  9. N017RW

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    Montelatici is Conflating Antenna structures with Part 15 Antenna requirements???
    Don't post information if your not familiar with it.

    Simply Googling 'FCC Part 15 Antenna', or similar, will get you the language.

    Part 15 is a performance standard.
    FCC does not do testing.
    DJI must demonstrate through the use of a certified testing lab that their equipment meets the performance standards.

    "Section 15.203 - Antenna Requirement
    Changing the antenna on a transmitter can significantly increase, or decrease, the
    strength of the signal that is ultimately transmitted. Except for cable locating
    equipment, the standards in Part 15 are not based solely on output power but also take
    into account the antenna characteristics. Thus, a low power transmitter that complies
    with the technical standards in Part 15 with a particular antenna attached can exceed
    the Part 15 standards if a different antenna is attached. Should this happen it could
    pose a serious interference problem to authorized radio communications such as
    emergency, broadcast and air-traffic control communications.
    In order to prevent such interference problems, each Part 15 transmitter must be
    designed to ensure that no type of antenna can be used with it other than the one used
    to demonstrate compliance with the technical standards. This means that Part 15
    transmitters must have permanently attached antennas, or detachable antennas with
    unique connectors. A "unique connector" is one that is not of a standard type found in
    electronic supply stores.

    It is recognized that suppliers of Part 15 transmitters often want their customers to be
    able to replace an antenna if it should break. With this in mind, Part 15 allows
    transmitters to be designed so that the user can replace a broken antenna. When this
    is done, the replacement antenna must be electrically identical to the antenna that was
    used to obtain FCC authorization for the transmitter. The replacement antenna also
    must include the unique connector described above to ensure it is used with the proper
    transmitter."

    So while there are no specific penalties for changing the antenna you can see that it may result in the equipment no longer being in compliance.

    Thus it is illegal for where it is being used.

    It is not out of the question that at sometime in the future folks who find themselves in trouble with the FAA may also come under scrutiny of the FCC.
     
  10. NRJ

    NRJ

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    I was able to find this on the internet on the FCC website. You seem to be correct, however, with any product that we buy, it must be tested for FCC compliance before sale. So, we would "expect" all antenna boosted or not to meet with FCC compliance. There is a grey area where it talks above about replacing the antenna of a unit. Below are my findings concerning both below.
     

    Attached Files:

  11. montelatici

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    The regulation states that the replacement antenna must be the same type e.g. dipole for dipole, yagi for yagi, must exhibit the same in-band and out of band ERP and must be permanently connected or utilize a proprietary connector. If the FCC was actively pursuing "pirates", they would be monitoring buyers of household range extending antennas that attach to wifi routers, with standard connectors for external antennas.

    By the way, if you fear FCC or FAA fines/arrest, gain can also be increased substantially through the use of a passive corner reflector without changing the antennas of the DJI remote control. You can find them for sale on Amazon. Of course the remote antenna array becomes directional with the reflectors. I would disable one of the DJI antennas, feed all the power to one of the dipoles with the 60 degree reflector and it would simulate 6 dipoles, the real one and five reflected images. They would produce almost the same polar diagram in front of the reflector as 6 driven dipoles would in the same positions. That would make the gain of one of the half wave dipoles and the 60 degree corner reflector about 11 dBd.
     
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  12. TheLightSpeedz

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    Hey guys, let me say this and it should sum this convo up nicely.... my head hurts. I do whatever DBS and MaxxUAV tells me to do. I think it's safe to say that you're all blowin my head up here. Thank you.


    Sent from my iPhone using PhantomPilots
     
  13. rstekeur

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    It's never going to make a difference and nobody will ever notice, until something happens and you have the fed's investigating you trying to hang you for any reason they can
     
  14. HWCM

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    Just change them and do what you want. No one will ever know or care. I have been flying and building for years and with people that have been flying and building for four times as long as me. We all use all sorts of antennas, on tripods, on roofs, amplified, 2.4ghz, 5.8ghz, 1.3ghz. At events in public, for shows etc etc etc. No one cares or checks or even knows to check. If you are that worried about it, just polish the quad up and set it on a shelf to look pretty.
     
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  15. lil boss

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    LOL.... Cute :D I Definitely Get Your Point !!! You Got Any Polish ??? :eek:
     
    #15 lil boss, Oct 12, 2016
    Last edited: Oct 12, 2016
    HWCM likes this.
  16. montelatici

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    I was trying to imply the same thing without actually writing it down.
     
  17. WetDog

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    Yes, the 13 cm amateur radio band encompasses the first 10 channels of 2.4 GHz Wifi frequencies on a secondary basis (has to accept interference - primarily from microwave ovens). Too lazy to look at but I think max EIRP (max radiated power, NOT just the amplifier power) is 50 W so a 3 watt amp and any sort of reasonable antenna would be OK.
     
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  18. WetDog

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    Although one certainly cannot explicitly condone such behavior, us being good corporate and social citizens as well as fine, upstanding folk the chances of causing interference with anybody else so long as you use the smallish amplifiers typically available is small. About the worse case I can think of is you running some bad amp / antenna combo RIGHT NEXT to a 2.4 GHz satellite downlink and interfering with reception. In that event, you'd probably have the techs running around with a sniffer and finding you and telling you to just go a half mile away and quit annoying them. Calling the FCC would likely be a hell of a lot more trouble than it's worth.

    If you're running energies higher than that for a Phantom class drone, you're doing something wrong and need to back to radio school.
     
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  19. NRJ

    NRJ

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    It's nice to know the law though, just in case you see the federalis coming. You will know how far and how fast to run. Lol.
     
    HWCM likes this.