Flying 2 meter repeater

Discussion in 'General Technical Questions and Answers' started by AF6HD, Jul 26, 2018.

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  1. AF6HD

    AF6HD Ham Member QRZ Page

    I have an interesting ongoing project just in the initial planning stages. I belong to Jefferson County radio amateur teams, a group supporting County government with emergency communications capabilities. There has been several discussions at monthly meetings what could be done to extend the range of our handy talkies. Various ideas were batted around and one that intrigues me the most is a flying 2 meter repeater.

    The vx-7r handy talkies I had were able to be programmed to act as a 2m repeater. That's kind of an expensive radio compared to the affordable Baofeng, and when it comes to a project of an RC flying aircraft with auto navigation, station-keeping and return to home base land features, when you're talking about being a handy talky that is only ever going to act as a repeater, it doesn't have to be fancy, just good enough to do the job. After all, there's not going to be anybody up in that little RC airplane punching buttons on the radio, so who needs fancy for that job? :)

    There has been quite a bit of research trying to sort out all the laws and rules that would entail in building such a device. I believe the FAA would require a drone pilot license, the RC airplane to be registered and numbered, and for some of the uses the Drone would be put to, a waiver for FAR part 107 would be required. It's early days as my research is just beginning, so I really don't know what I will find out about all the laws and regulations involved.

    So far I've managed to find an RC aircraft and all the controls (with GPS) where the Drone could be launched, Circle above a pre-programmed point, with an automatic return and land function.

    Even though the capabilities of technology and electronics has come down quite a bit, that's still asking quite a lot of an RC drone to do, so I don't see how you can get the bits and pieces to build anything like this for less than 1500 bucks.

    That being the case, my research will probably last for a while, as all research cost is my time, and that's about all I can afford in my budget at the moment. :)

    To keep cost down, rather than something pricy like a VX-8R, I'm thinking of a Beofeng handy talky set up with a Simplex controller and long trailing antenna to be the repeater.

    I'm certain that this being such an interesting concept, many will have quite a few good ideas to share and discuss how they would go about building a flying 2 meter repeater,

    73s AF6HD
    Last edited: Jul 26, 2018
  2. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    You'll probably get more responses by posting up your question in one of the technical forums - or even in Ham Radio Discussions.

    This forum is about discussing stuff for sale, how the for sale section works, selling rules and policies, etc.

    Good luck with your project either way

    K9ASE likes this.
  3. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    I don't know a lot about drones, and I'm sure you'll find out everything you need to know.

    But remember using a hand-held as a "repeater" means it will be a split-band repeater (2m/70cm) so only those with dual band rigs will be able to use it. Obviously, "payload weight" is important considering the vehicle, so I'd try to pick whatever is lightest weight yet still has good battery life, preferably as long as the drone's is.:p

    Also: Re the antenna, remember the antenna needs to provide a reasonably good impedance match to the transceiver on both bands. Just some trailing wire won't do that, but with some careful engineering it can certainly be accomplished.

    Sounds like a fun experiment! Let us know how it all works.
    AF6HD likes this.
  4. W9KEY

    W9KEY XML Subscriber QRZ Page

    One thing to check early on is payload capacity versus drone run time. Most common commercial drones fly for 25 minutes max on a battery - some are less than 10 minutes. If building one from scratch, i suppose battery options are available, but adding capacity will reduce your payload.
  5. KD4UPL

    KD4UPL Ham Member QRZ Page

    A Yaesu HT (or any HT for that matter) can NOT be turned into a 2 meter repeater. Some of them can be made into cross-band repeaters. There's a big difference. If you do make a cross band repeater then every user would need to be using a dual band HT set up for a cross-band split. I don't know how many of them will do that. Probably a lot. My old Yaesu FT-530 can be a cross band repeater and it will do cross band splits.
    I don't know the terrain or coverage area you're working with but the idea of using a drone to fly a repeater seems overly complex too me. Sometimes you just have to step up and use a real radio instead of an HT when trying to communicate reliably over distance. A mobile rig with a mobile antenna is far and away a better station than an HT.
    Or simply connecting an HT to a mobile or base antenna will make a huge difference in communication range.
    Often, when I am in a public service function I will carry my HT and set up the mobile rig in my vehicle as a cross band repeater. This gives my HT a big "boost" in both reception and transmit range. It doesn't require anything special on the part of any other operators, they normally don't even know that I'm doing it. Many of the hams in my area do this for public service events that we support in the mountains of VA and WV.
    AK5B likes this.
  6. K3XR

    K3XR Ham Member QRZ Page

    That would seem to be a big problem. Have one of the DJI Phantom drones no way they would handle that sort of weight one of the larger "commercial" types may be able to handle it. The other thing that comes to mind is interference from the HT to the operation of the drone.

    As to RC winged aircraft they have some large models believe up to quarter scale don't know about flight time.
  7. W9KEY

    W9KEY XML Subscriber QRZ Page

    Thinking about this some more - as much as I like playing with drones, have you considered a few good-old-fashioned weather balloons, a tank of helium,, and a lightweight tether rope (kite string)? Obviously it could not fly a programmed pattern like a drone (although unless you're a commercial operator, you are limited to 400' and line of sight), but it would have a long mission time, being able to stay "on station" for many hours. And instead of flying all the repeater radios, power supply, etc. - a balloon might simply be able to hoist a fine wire antenna to a pretty decent altitude.

    Anyway - just a thought.
    Fred, W9KEY
    AK5B and K3XR like this.
  8. WB2WIK

    WB2WIK Platinum Subscriber Platinum Subscriber QRZ Page

    Except a very long, fine wire antenna would not work well on 2m or 70cm. If fed at the bottom, almost all the radiation would be "straight up."

    The balloon (or better still, kitoon, which is more stable) is better suited for HF work where a long, fine wire antenna fed against a decent ground system can be an excellent antenna and will radiate more towards the horizon -- especially on 160m.
  9. W7UUU

    W7UUU Principal Moderator Lifetime Member 133 Administrator Volunteer Moderator Platinum Subscriber Life Member QRZ Page

    Note that this thread was originally started in "Swapmeet Chat"... hence my response.

    Moderators have obviously moved it but neglected to indicate that :)

    AK5B likes this.
  10. KP4SX

    KP4SX Premium Subscriber QRZ Page

    A single band "repeater" is likely to need to additional filters/cavities. Add that to the weight loading.
    KK5JY, AK5B and K3XR like this.
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