DX6, 1 Tx and multi Rx's at the same time question.

[Hoghappy]

What happens when I go from one boat selection to another without turning off any of the receivers? I want to use my new DX6 for all my boats to include my sail boat and the rescue tug due to only one radio to carry to the pond and no interference issues. Let’s say I’m using my DX6 for boat #1 and run it aground. What will happen if I change over to the rescue boat (boat #2) setting on the transmitter without turning off the boat #1 receiver? They are both programmed into the same transmitter with different receivers. Will the boat #1 servos start glitching when I make the switch to control boat #2 or will the boat #1 servos go to a “preset loss of signal setting” and just stay there without possible damage due to glitching? :confused:

Or..do I need to carry a seperate radio for the tug?

Capt. Crash

[Kmot]

Interesting question. I never tried it. Just set them up on the workbench, turn them on one at a time and see what they do.

[Umi_Ryuzuki]

I have two boats on the spektrum, but I don't think I have ever had more than one on at a time. I have, however tried to run the fireboat with the transmitter set to Model 2, the SDM tug. The saved trim settings for model 2 do not work for the fireboat.
But I just had to reset the transmitter to model 1 to solve that


I might have to try this later...

[CG Bob]

You will have some problems with trying to run two boats on the same frequency at the same time. In your example of boat #1 being aground, and you'll be sending boat #2 out to rescue boat #1; if you get boat #1 free, you may have problems controling the tow or push back to shore. When you give a rudder command to one boat, both boats will be receiving that signal and the disabled boat may not turn the way you intended it to turn. If the disabled boat is also a power boat, you will be contolling it's motor at the same time you're trying to move boat #2 into position. If the disabled boat is a sailboat, moving the rescue boat throttle to full ahead will affect the set of the sails. I assume that the boats are set up as different models in the computer memory of the radio. Are there differences in how the controls are set up between the two boats? For example, is the rudder on boat #1 set for normnal throw, and boat #2 set for reverse throw. How about EPA for the servos, are they the same for all boats? Probably not, at least not on my radios with a model memory.

Best bet is to get a separate radio for the rescue boat.

[Brooks]

I have both my barque and my tug on the same DX6. Like you, I wish to limit my lug of equipment to the pond. As CG Bob states, there are some operational difficulties running both boats at 1 time, say when sending the tug out to retrieve the barque if the wind fails. Both RX's will respond to the single TX whenever I move the joysticks.

There are 4 proportional channels on the 6 channel TX, 2 per joystick, and 2 non-proportional channels, basically on/off switches. The tug needs 3 channels - rudder, motor, fire monitor. I put the fire monitor on an on/off channel, so the tug needs 2 proportional channels. The barque needs 3 proportional channels - foremast+jibs, main+mizzen+jigger masts, rudder. So, I need a total of 5 proportional channels and have only 4. I double up the distribution of channels, - rudders on the same stick for both ships (aileron). The other channels can be kept on separate axes of the sticks.

The arrangement is not impossible to use, but, besides the natural confusion of wiggling the wrong stick, there are problems with having both rudders move in synchrony. If the barque is dead still, waggling it's rudder while motoring out with the tug is not too bad. But if there is enough whisp of a breeze to make the barque move, then catching her with the tug's towline can be a challenge :-). My snagging method desires the casualty to be sailing in a straight line - but when I move the rudder of the tug to get her into position to snag the barque, the barque will turn away from the approaching towline, due to synchrony of rudder travel, hoho. Practice is necessasary to learn successful approach techniques... and a good "nautical" vocabulary :-). I thought I was hot stuff, catching the dead ship fire tramp with the towline 80-90% of the time, but learned that catching a recalcitrant barque, still alive and moving, is a different kettle of fish *smiles*.

And, of course, once the barque is hooked up, she still tries to escape, turning to force slack in the towline whenever I turn the tug. Turning the tug is necessary, because a breeze against the backwinded sails will cause a lot of drag. In any sort of breeze, I must tow a zigzag path upwind to get back to the launch area (yes, I have to tack the barque sails on each leg). Well, if it were easy, I'd soon get bored, right?

[Hoghappy]

Best bet is to get a separate radio for the rescue boat.

RATS!

You’re saying the transmitter doesn't pick different frequencies for simultaneous transmission to different receivers....right? Are you saying when you select boat #2, it’s still sending a signal to boat #1 on the same frequency?

I guess I will try what Kmot said...bench test. It will have to be the sailboat and bass boat (2 of the 3 that I already planned to put new receivers in), cause I don't want to switch out gear in the tug unless it's for keeps.

Capt. Crash

[Hoghappy]

Ok...thanks Brooks...I think I have it now. Too bad...it would of been nice to use only one radio (with the same controls) for both boats independently.

Capt. Crash

[AndyKunz]

Here's another reason to have a separate radio for the rescue boat:

What happens if the reason your boat is stranded is the dead transmitter?

With old radios what you want to do wouldn't have been so bad, but the modern 2.4 radios, they are not "transmitter" and "receiver" any more - they are both transceivers (they talk back and forth to each other). Your handheld (old technology "transmitter") will probably be a little confused by having two remote modules (old technology "receiver") talking back to it.

Sorry, but there are several reasons you need to have the rescue barge on a separate handheld.

Andy

[Ghost 2501]

idea, boat 1- left stick boat 2 - right stick

[CG Bob]

RATS!

You’re saying the transmitter doesn't pick different frequencies for simultaneous transmission to different receivers....right? Are you saying when you select boat #2, it’s still sending a signal to boat #1 on the same frequency?

Capt. CrashYes. The tx will send signals to all energized rx's that are bound to it. Differences in rx battery voltage, as well as servo and ESC setb ups will make it difficult to try to control two boats at the same time. When I go to the lake, I take at least two boats on different frequencies; one boat is the designated SAR boat.

[toesup]

Just theory...

As its a 2.4 system and each Rx is 'bound' to the Tx... when you switch from model 1 to model 2, wont model 1 disregard what is being sent to model 2 and just go in to failsafe mode?... :o

[Brooks]

I believe the way it works with the Spektrum I have is that the RX is bound to the serial number of the TX. The RX will only pay attention to signals prefixed by that particular serial number. The TX does not know, or care, about the serial number, if any, on the RX. The car-racer Spektrums may have a different setup, since the car RX's can transmitt data back to the TX. When I asked Spektrum if I could use car rx's with my parkflyer tx, they said no (Andrew was urging me to get telemetry from the barque). I did not ask if the "no" was technical or legal.

[Kmot]

Check this out!

http://www.modelaircraft.org/news/radioservice.aspx

[Hoghappy]

Just theory...

As its a 2.4 system and each Rx is 'bound' to the Tx... when you switch from model 1 to model 2, wont model 1 disregard what is being sent to model 2 and just go in to failsafe mode?... :o

Toes...that's the same thing I was thinking...but...wouldn't the transmitter have to broadcast on multiple frequencies simultaneously (other than the 2 it is already on) in order to do that?

My radio is due in today so I hope to try this this weekend. Anyone with this radio already try it?

Capt. Crash

[LtDoc]

It means that the one transmitter, even if 'bound' to two or more receivers, is sending the same control signals to all 'bound' receivers. They are all being told to do the same thing. If the same channels are used for the same function, then 'both' boats are gonna be trying to do the same thing. Not exactly the best thing to happen if one of those boats is 'stuck'.
If the radio system has multiple channels, and you can split those channels between boats, then you can make them do different things at the same time (the problem is keeping track of what does what, and how). So, two (or more) boats at the same time is certainly possible with a multi-channel radio system. Ummm, how many of those control channels are proportional? Two boats? Probably. More than two boats? Maybe not?
- 'Doc

[ropanach]

I have a DX7 spectrum, and being a little long on time, I thought I would test this unsolved problem.
what I found was that with one boat on and the other boat off I had control of the one boat no problems, leveing boat one on and switching boat two on at the same time could not get control of boat two, but if I shut down the tx and turnd it on again it would look for the rx and lock on to one or the other after a long search, a flip of the coin as it were, you can't count on it hitting the same boat twice. hope this helps.

[Hoghappy]

Well that's interesting! So...if it's a random choice of which receiver it finds first and locks onto just that one receiver....than...follow me here....I should be able to turn the transmitter on and off until it locks onto the boat I want and not have to worry about both boats responding to the commands at the same time...right? This may work yet! So...what happens to the servos in the boat NOT locked onto? Do they glitch?

Capt. Crash

[ropanach]

I find that the boat that is not locked on to just sets there because it is not beeing told to do anything, but if you are on boat one at the tx and it locks on to boat two it will fallow the tx signal for boat one. I am doing this in my shop so don't know how it will work on the water, the same I assume.

[Brooks]

Ropanach, your experience is completely different from my summer's sailing with my DX6. I always can control both boats when both rx's are *receiving sufficient voltage*. Binding never failed, no matter which boat I activated first. I don't have a DX7, so can't compare.

I had lots of trouble with the barque losing signal to the rx in heavy winds until this was explained to me by a tech guy at Dimension Engineering. If your batteries are low in voltage, or low in ability to deliver volts/amps (ie old batteries), then the tx-rx talking is spotty, only happening when there are no servos moving and drawing power. All my problems with TX talking to RX were solved when I a) got new batteries b) changed to using the DE Sport Bec in the barque (a separate unit to convert Lipo bat voltage to 6 volts for the servos) instead of a spare esc. Esc's are not designed to deliver as much power to the system as the SportBEC. In my high drain circumstances, moving yards against heavy wind pressure, the esc failed to keep up with the power requirements. You'll notice in the instructions for an esc that it lists a limit on number of servos, and on their size. Interestingly, the limits go up when you decrease input voltage (phenomenon only noticed if the batteries are capable of delivering the amps in the first place, of course).

I have had other experiences (RC live steam locos) where puzzling behaviour of the Spektrum DX6 system was solved by replacing the RX batteries. Consequently, whenever I have problems, RX batteries are the first thing I replace. And of course, if your TX batteries get low, you will have puzzling behavior :-). Perhaps your DX7 results are due to same causes?

http://www.dimensionengineering.com/SportBEC.htm

The DE tech guy's letter to me here:
http://www.rcgroups.com/forums/showthread.php?p=8254930&highlight=sportbec#post8254930

[Hoghappy]

Uhhhhh...I just realized we may be talking apples and oranges....I'm not sure the DX6 and DX7 work the same. DX7 is newer technology. Perhaps this is why the DS7 works differently than the DX6.

"Spektrum engineers have come up with two more patent-pending innovations that you’ll wonder how you ever lived without—ModelMatch™ and ServoSync™.

ModelMatch puts an end to the “wrong model” syndrome. Almost everyone that flies RC has, at one time or another, crashed, or seen someone crash, because they neglected to verify the model name on the transmitter display in their preflight check. With the DX7 a unique code is embedded in the signal so that if the wrong model’s name is on the screen, the model’s controls simply won’t respond."

Meaning you can't control 2 or more receivers at the same time off one transmitter?

Capt. Crash

More on the subject:

Q: What is Model Match?
A: Model Match™ (patent pending) prevents the pilot from flying a model using the wrong memory. During binding (the process of teaching the receiver the specific code of the transmitter), the receiver actually learns and remembers the specific model memory that is selected during binding. Later, if the system is turned on and a different model memory in the transmitter is selected, the system will not operate. This prevents the disastrous issue of trying to fly a model using the wrong model memory. Simply selecting the correct model in model memory will cause the system to connect.

Me thinks me want's the DX7 now....RATS!!! :censored:

[Brooks]

Thanks Hoghappy, that explains the difference tween the 2 systems all right :-). Do you know if you can change between the 2 ships w/o turning off the tx?

Also, what happens to the "off" ship, do the servos go to some failsafe point? DX6 offers 2 different rx's, the standard one with only 1 failsafe-programable channel (throttle) and another rx, the robot one, where all channels are failsafe-programable. I ran into a problem with the standard type when my batteries dipped in voltage - the sail control channels would go to neutral (yards braced square) for a second or two, and then flip back to braced sharp (the joystick setting) when the batteries recovered. This was a problem in strong winds because it made the rig flap back and forth in the heavy winds. So, losing your TX signal may not leave the Prince in the condition you'd like, if the servos go to an undesireable failsafe - the robot rx might be a help here. As long as I had sufficient battery capability to not have a voltage drop when the servo worked hard, though, I never had the flapping problem when running the tug out to snag the barque (mostly done in light-zero wind).

[grizzlyone]

Re rescue boat on DX6, here's a thought if you've got a simple 2 channel set-up on your boat...
Use two P-mixes in the programming of the second model.
RX channels are T, A, E, R.
If you use T for throttle/sails, and A for rudder...
Plug your ESC/Sail servo into E and Pmix T(Master) to E(Slave) at 100% but set travel on T to 0% and E to 100%
Plug your rudder servo into R and PMix A(Master) to R(Slave) at 100% but set travel on A to 0% and R to 100%.

This should allow you to switch the model selection in the TX to the second model and operate it with normal sticks without affecting the first model...

Worth a try... I haven't tried it.
Cheers,
Mike

[mfr02]

An advisory from Futaba. New purchases should be unaffected. Hopefully.
http://2.4gigahertz.com/techsupport/service-advisory-tm7-7c-6ex.html

[Brooks]

Cool idea Grizzlyone, thanks! Basically you are saying, if I understand you correctly, that you a) set up rudder on different sticks for each boat (by plugging rudder servo into different ports on the rx, b) "turn off" the rudder stick not needed with the mixer and turn on the function needed (essentially reprogramming the stick to activate a different port), c) pick the model you want to run, just having to remember which stick is now controlling the rudder and that the old "rudder stick" is now controlling the new port.

[grizzlyone]

Brooks,
Sorta... that idea would use the regular sticks to drive different RX channels.
Once it was set up it should operate 100% normally (or not at all:rolleyes: ).
Cheers,
Mike