transmitter?

Discussion in 'Radian' started by Gustav Raberg, Feb 13, 2013.

  1. Gustav Raberg

    Gustav Raberg Member

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    This is the only way to have to hott receivers ( and run them safely) on the same copter as we use them.

    This is also confirmed with graupners service team here in Europe.

    G
     
  2. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Well done, Gustav!
    As far as I am aware, you're the first person to have solved this problem, so we should call this approach the Raberg Solution! :)

    Thanks
    Andy.
     
  3. Gary Haynes

    Gary Haynes Administrator
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    Gustav, you mention that this was the solution for an MX-12. Did you ask Graupner if or how that would work with their other transmitters like the MX-20, MX-16 and MC series? One size for a specific transmitter, MX-12, might not work for all of them.
     
  4. Josh Lambeth

    Josh Lambeth Well-Known Member

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    I am running 2 HOTT receivers on my copter that are both tied to my MX20 and don't have any issues.

    Josh
     
  5. Dave King

    Dave King Well-Known Member

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    This is a bit confusing to me so I ask someone to clarify.
    Is this a problem if you use a TX/RX that are binded together, and another TX/RX pair that are binded together? I'm going to use a MX20 with a GR24 and a MX12 with a GR12. The MX20 won't be bound to the GR12 and the MX12 won't be bound to the GR24. I plan on using them completely separate. Also the GR12 doesn't have a telemetry port just 6 channels does that matter? Very confused! :confused:
     
  6. Howard Dapp

    Howard Dapp Active Member

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    I don't use telemetry at all and I don't own HoTT equipment so I'm assuming the issue is with HoTT RXs and the fact that they transmit wireless data...with both being so close in proximity to each other I can see a possible clash. Is this the issue?

    Just to confirm, is there anyone having any range issues using non HoTT equipment running a two man setup? (Gimbal and multi running their own separate RX being controlled by two separate TXs)
     
  7. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The problem apparently occurs if you have a two-person setup using two Graupner Tx and two Graupner HoTT Rx.

    If you bind Tx 1 to Rx 1, and then bind Tx 2 to Rx 2, both Rx are going to attempt to transmit telemetry and they will contend with each other, possibly causing problems with the Tx/Rx 1 or Tx/Rx 2 control links as well as the reverse direction telemetry.

    The problem does NOT occur when you bind Tx 1 to Rx 1 and Rx 2. The system is smart enough to realize that both Rx shouldn't be transmitting telemetry, so, in this case Rx 1 shuts down it's telemetry. Here's the section of the GR-24 documentation that describes this:


    2.1.1.Binding“ multiple receivers in one model​
    If required, it is also possible to bind multiple receivers to the transmitter for a particular model. The first​
    step is to bind each receiver individually using the procedure already described.​
    When the system is in use, the receiver which was bound last is the Master receiver. Any telemetry sensors
    installed in the model must be connected to this unit, as only the Master receiver transmits sensor
    data using the downlink channel. The second and all further receivers operate in parallel with the Master
    receiver but in Slave mode, with the downlink channel switched off.
    The control functions can also be distributed amongst multiple receivers; this is carried out using the​
    Channel Mapping function of the SMART-BOX (Order No. 33700). In the same way it is possible to assign​
    one control function to multiple receiver outputs; a typical example would be the use of two servos​
    for each aileron instead of only one, etc.​


    So what Gustav did, rather cleverly, in my opinion, was to reason like this :

    1. Well, if I do what the manual says, and I bind the camera operator's Tx 2 with Rx 1 and Rx2, then Rx 2 will be the Master (see above), and Rx 1 will shut off it's telemetry.

    2. Rx 1 will remember that it's the "slave receiver" and its telemetry will remain shut down.

    3. Rx2 becomes a spare and is not powered on.

    3. Now, with with Tx 1 (the pilot's), I'll bind it to Rx 3 (yes, you need three Rx for this to work).

    Wahey!

    Now we have this arrangement:

    Tx 1 (Pilot): Rx 3 acting as a Master and transmitting telemetry.

    Tx 2 (Camera op): Rx 1 was bound as a "Slave Receiver" so its telemetry is disabled.

    This is precisely what we've been pondering: How do we use two Graupner Tx with two Rx such that the gimbal Rx is not transmitting telemetry. So, that's why I call this the Raberg Solution in Gustav's honour. :)

    Andy.
     
  8. Gary Haynes

    Gary Haynes Administrator
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    And yet I did a test last weekend, albeit on the ground and not flying, posted HERE and found I was getting all telemetry and correct signals and control with an MC-32/GR-16 (Copter) and MX-20/GR-16 (Gimbal) with no issues out to 1.5 miles distance.

    Lots of variables and combinations make this almost a situation of your needing to try your setup and fully test the combination that you have and continue to test until you are comfortable. And it only seems to be an issue with Graupner and the telemetry from the MK boards. I guess I don't understand why others, (Futaba/Spektrum) which also send their own types of telemetry,wouldn't have the same types of problems. Isn't that the purpose of 'binding'? I don't hear of folks at an RC field having issues with lots of transmitters in operation having an RC plane suddenly start doing it's own thing.
     
  9. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Yeah, I agree with you it's very confusing, Gary -- but primarily because we don't understand the phenomena we're dealing with.

    My understanding of the binding process is really one of allowing the Tx and Rx to recognize the data packets that they see on shared frequencies so that they can identify "their data" while allowing multiple Tx and Rx to use the same frequency. It could be that having two Rx on a copter transmitting telemetry only causes problems because of the inverse-square law -- if the Rx are only a few inches apart, then the telemetry signal from one swamps the other?

    It's certainly worth using the "Range Check" feature in the transmitters to make sure that all is well before you lob the bird skywards.

    But, as you can tell, I think the Raberg Solution is an elegant one.

    Andy.
     
  10. Dave King

    Dave King Well-Known Member

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    Please excuse my question in advance if this is stupid but the GR12 receiver doesn't have a telemetry port on it. How can it transmit telemetry if it can't receive telemetry input?
     
  11. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    Hi Dave:
    If there's a GR-12 non-HoTT then you're correct.
    However, the GR-12HoTT uses port 5 for the Telemetry I believe. Check this page.
    and look closely at the image for port 5 -- there is the letter "T" below the 5.

    Andy.
     
  12. Dave King

    Dave King Well-Known Member

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    I see you are right! Crap!
     
  13. Dave King

    Dave King Well-Known Member

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    Interesting: Is this a process you have to do every time you power up? How will RX 1 know that there is a RX2 if RX2 isn't powered up? Will RX1 just remember that its a slave RX after RX2 is bound the first time?
     
  14. Andy Johnson-Laird

    Andy Johnson-Laird Administrator
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    The receiver's "maintain state" when they're powered off, so you do not have to re-bind them each time you power up.

    Andy.
     
  15. Sam Slape

    Sam Slape Member

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    So for those of you who live close enough you could swap a receiver each and then swap back, just make sure you don't fly nearby each other!
     
  16. Howard Dapp

    Howard Dapp Active Member

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    Anyone flying two Futaba radios and RXs (dual setup)? any range issues?
     
  17. Dave King

    Dave King Well-Known Member

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    The Raberg Solution is very clever!! My question is why would a receiver be transmitting telemetry if there's no input telemetry going to it?
     
  18. Gary Haynes

    Gary Haynes Administrator
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    Dave the Graupner RX's all transmit information like the voltage at the receiver.
     
  19. Gustav Raberg

    Gustav Raberg Member

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    Wow the "raberg way"! I can't take all the fame. I went thru all forums looking for answers and had great support from the guys at graupner.

    Just to clarify, this is for all hott rx (gr12,16,24) running in the same copter with two tx at the same time. There is a lot of guys out there running this configuration without problem. Gary is a good example (great test by the way). But there might be a problem and this is confirmed by graupner. The problem is the telemetri signal back to the tx and there is no way to turn it off so the prenciple is to fool the tx.

    Ok I will try to explain the "raberg way" :)
    This only concernes the cam op tx/rx ( you don't have to bind or do anything with the pilot system and I explain later).
    You would need in total three rx for this ( including the pilot rx).
    When you get your system (mx12,16,20,32) the tx and the rx in the box is already bound tho each other so you need tho bind another rx tho your cam op tx as a slave. When you bind a new rx to the same tx the telemetri automatically runs thru just one of them. So now you have two rx bound tho the same tx with only one sending the telemetri, now you mount the new tx to the gimbal and leve the other at home in a box. When you power up your system you would get a warning pip saying no signal from the tx this is the system telling you you forgot the rx in a box at home but you have the slave rx bound and fitted to your gimbal working so you can ignore the pip and turn the volume down in the tx.

    Some might think you can use the pilot tx and bind the cam op rx first to that and then use it for the gimbal tx, I thought that too until I got a mail from graupner saying that wont work because you need two rx bound to the same tx to shut of the telemetri signal.
    So if get that right if you have the cam op rx bound to the pilot tx it won't send the telemetri signal since the pilot rx is already doing that. But once you power up the cam op tx and the cam op rx ( which is bound to the pilot tx as a slave) it would send telemetri for the cam op system since that rx is the only rx bound to that tx, meaning you would still have two telemetri signals coming from the copter.

    Phuuu that was like running a marathon trying to explain that :) hope you understand it!?

    I also have to add that this is not tested yet by me because I did all this research when I was waiting for my mx12 to arrive. And when I got it I only had two rx (including the pilot rx) and I would need three in total to make it work so I didn't unbox it, I had to go to the local shop and get a Futaba (they dont stock graupner) because I had an important shot to go to ( wich was blown off due to a snowstorm :) )

    G
     
  20. Gary Haynes

    Gary Haynes Administrator
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    So since I am are in blizzard conditions unable to fly I a the test and it appears to work fine.

    1. On the MX-20 Bind the receiver you want to control the gimbal first.
    2. Bind a second receiver that you are not going to use.
    3. In my test I had a GR-16 on the gimbal and the second unit was a GR-24.
    4. You can see the results on the Base Setup screen. Under the left hand Bind Rcv Ch Map I see R08 and the right hand side R12. Which corresponds to the GR-15 and GR=24 respectively.
    5. Turn on the gimbal with the the #1 RX running.
    6. On the MX-20, tap the right arrow on the left side control wheel and you will get a message - "Can't Receive Data - OK"

    The data is turned off. Doesn't appear to matter what type or combination of receivers that are used, just the order in which they are bound.
     

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