Radios for your ALTA?

Discussion in 'ALTA' started by Steve Maller, Jun 24, 2015.

  1. Steve Maller

    Steve Maller UAV Grief Counselor

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    Like quite a few others here, I'm awaiting delivery of my ALTA, and am contemplating how I'm going to configure the radio systems. I thought I'd start this thread for everybody to discuss how they plan on configuring their machines, as Freefly do not ship the ALTA with either control receiver or FPV transmitter.

    As I understand it from conversations with the folks at Freefly, and now from the official spec sheet which they've just released (click here to download the PDF) you have many different options for radios on the ALTA.

    Screen Shot 2015-06-24 at 8.16.26 AM.jpg

    For my FPV system, I plan on using the same 400mW 1.3 gHz video transmitter I use on most of my copters, including my former heavy lifter that the ALTA is replacing. I use this on my MōVI, too. I am able to do so by using not only different channels (obviously) but also using a RHCP on one and a LHCP on the other. I've found at the distances I normally operate my big ship, I get rock-solid video performance. It also gives me redundancy in the event that one or the other of the systems is having interference issues.

    For my control radio, I plan on eschewing the typical Futaba/Spektrum/Graupner 2.4gHz route and instead using the 433mhz UHF DragonLink system. I've been using it on a long-range quadcopter I built and I've been able to fly to the limit of my battery (5 km radius) with rock solid radio reception. I do not plan on flying anywhere near that far (nor could I with the ALTA) but there are other significant advantages to the DragonLink. For one, UHF is virtually impervious to many of the pitfalls that can easily kill a 2.4gHz signal. UHF can penetrate trees, houses, and even terrain in certain situations (as can 1.3gHz vTX). This means you don't have to be quite a careful about flight planning as you do with 2.4 systems. You also don't have to be concerned with Wi-fi or cordless telephones or other electronics interfering with your signals. And like 2.4gHz, it's a digital signal that can co-exist with other people flying on the same frequency.

    Because it's a standalone radio module, DragonLink allows you to use the transmitter of your choice, to a certain degree. I am going to use the FrSky Taranis, a very nice openTX-based transmitter with many programmable switches and pots. It's a fraction of the cost of a comparable Futaba or other radio, and is available without the transmitter module at all. The DragonLink simply plugs into the back of the Taranis and gets both power and signal from it.

    The only real thing I lose with this configuration is any sort of telemetry through the radio. However, I intend on using Synapse's built-in OSD for delivering telemetry information in addition to the view from above. In my experience, I'm less comfortable with the telemetry appearing on the transmitter screen than I am glancing at my video screen. And the reality is that the telemetry link is yet another radio system (logically separate TX/RX) that in my experience can be a weak link.

    Lastly, it bears mentioning that the DragonLink can output standard PPM of up to 12 channels, so it should work well with the Synapse flight control in the ALTA. But I won't know for sure until I get it. I don't know if Freefly have tested DragonLink with ALTA. If for some reason it has a fundamental incompatibility, I can revert to another solution.

    Here's a sample video of an epic flight I recently made with my long-range quadcopter using the same control and FPV system I intend to use on the ALTA. As you can see, control was flawless and video (look at the ground recording of the FPV link) was also very clear all the way out to 5km and back.

     
  2. Jason Smoker

    Jason Smoker Active Member

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    Thanks for the info steve time for a upgrade haha
     
  3. Klaus Friedrich

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    Lucky one - you don't live in Europe :)

    Well, here you are not allowed to use any not "CE marked" radio. Using it privately you might not have any problems as long as you don't have any incident where you need your insurance. But for commercial business? Forget it - as long as this EU still exists ;)
     
  4. Mark Hoffman

    Mark Hoffman Active Member

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    My experience with UHF systems has been hit or miss. These systems get incredible range partly due to the fact that they use very sensitive receivers, unfortunately this comes at the expense of being more susceptible to interference in my experience. I've never used a Dragon Link and its been a few years since I've used any UHF system so they may be more robust now but I'm going to stick with my trusted Futaba 10C.
     
  5. Steve Maller

    Steve Maller UAV Grief Counselor

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    Team Blacksheep just announced this new long-range radio called Crossfire. It's quite intriguing, as it has some novel features unlike most other radio systems out there today. They call it "UHF" although it uses 868/915mHz, not the 433mHz that Dragonlink and other UHF systems use. Here's the feature list from their product page (http://team-blacksheep.com/crossfire). It's about US $333 for the TX/RX combo. Very interesting...
    • Long range, adaptive and robust remote control system for your aircraft
    • Immune to on-board noise
    • Two-way communication link with real-time link vitals and telemetry
    • Self-healing & frequency hopping (DSSS, FHSS)
    • RX beacon mode to recover your downed aircraft
    • Super easy binding and configuration via built-in display
    • Low latency control for perfect immersive feeling
    • Two receiver models: 8ch Diversity Rx, 8ch PPM Mini-receiver (4g weight!)
    • Ability to fly with multiple friends at the same time (10 or more)
    • Selectable RF power from 10mW to 2W (local restrictions apply)
    • Dedicated head-tracking input option for full FPV immersion
    • Transmitter LED shows link health, OLED display for built in configuration
    • Bluetooth telemetry output for smartphone apps
    • Expansion port for future feature support
     
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  6. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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  7. Steve Maller

    Steve Maller UAV Grief Counselor

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    I am not sure this will be all that useful for my ALTA, as it's clearly part of an integrated system that utilizes TBS's other electronics (Blackbox, Core OSD, etc.), but my long-range custom copter with the NAZA-M V2 is about to get an upgrade to those TBS gizmos, so I'm tempted to try the Crossfire on that one. But I think I'm going to have my hands full with the ALTA when it arrives.

    Is it August 3 yet? ;)
     
  8. Gary Haynes

    Gary Haynes Administrator
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    Two items to check off. Is it FCC approved? I don't see anything in the documentation with an FCC approval number. FCC for ISM bands is max 1w (30dbm). The transmitters in the ISM band are 'unlicensed' so not likely to get an FCC id number. Not sure that having an amateur radio license would make a difference and allow you to use the full output power. This should help you count sheep tonight http://www.arrl.org/part-15-radio-frequency-devices or this shorter version http://www.afar.net/tutorials/fcc-rules
     
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  9. Steve Maller

    Steve Maller UAV Grief Counselor

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    Trappy has said they've done extensive testing at the lowest power settings and have gotten serious range at 25mW. DragonLink runs at 250mW or 500mW, and most of us have gotten miles and miles out of the lower power setting. So I'm not sure why they went all the way to 2W other than they're Team Blacksheep and...well, you know. ;)
     
  10. Steve Maller

    Steve Maller UAV Grief Counselor

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    Ahh yes...reading standards documents: the cure for insomnia. :confused:
     
  11. Steve Maller

    Steve Maller UAV Grief Counselor

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    Update on ALTA #1 (currently on my living room floor)

    I originally intended to use my DragonLink UHF setup, which has impressed me greatly on my long-range quadcopter. It's a revelation to no longer even have to think about the RC link to my copter.

    But when I was up at Freefly yesterday, I had a long talk with Tabb about RC radios, and I have decided to go with the same Futaba setup that Freefly are using on their ALTAs (14SG with two receivers running telemetry to the TX and diversity through the Synapse). Revisiting my motivations for going with the fully-integrated ALTA, I realized it could be foolish to use a RC radio other than what they've been flying. After all, I really appreciate the support system at Freefly, and it'd make their job easier in diagnosing issues for me if I'm running an identical setup as their test machines.
     
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  12. Aj White

    Aj White Member

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    Congrats Steve btw!! Yeah I'd love to get the exact same setup when mine arrives... if you could share your setup process that would be awesome as well :)
     

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