Spektrum Receivers?

breeze400

Spagetti Pilot
:dunno::dunno::dunno:

Has anyone ever heard of binding two receivers together on one transmitter for running the same plane? My tech friend doesn't like the idea of y harnessing 4 servos for my flaps together on one channel of my receiver. Since I only have a dx7 and I need all 7 channels to run the plane, he said to use two receivers. Anyone ever done this? Do you need to use two of the same receivers? Or can I use a ar7000 and a ar6200 to do this? I did not know this was possible. It must be if he said it was. What do you all think?
:feedback::feedback::feedback:
 

RandyDSok

Well-Known Member
Using two recievers will not give you any more channels on your transmitter ( ie 7 ) ...

My Futaba 8FG transmitter is actually a 14ch TX... so I could, with the correct recievers that allow them to be "joined", could use two 8ch recievers giving me 14ch's on the recievers... but as I mentioned I've got 14ch's on the transmitter in order to be able to achieve something like you are asking about.

Another issue that you may need to address using that many servo's... does the power supply for your system ( ie either the BEC or a reciever battery ) have enough power to supply all of the servo's what they need... I would recommend at a minimum at least 4a of current and would prefer 5-10a if possible.

Servo's normally don't pull a lot of amps except in certain situations such as high stress loads or when binding... So you want to over spec you power source for the worst case so you don't end up starving your reciever which is a common issue on Spectrum recievers... When this happens, it is called a brown-out and is a major cause of crashes being reported by Spetrum users.
 

breeze400

Spagetti Pilot
No I would be just using the flap ch. On the extra receiver. Joined with the flap ch. On the other receiver. Has far has power is concerned. This plane has 13 servos altogether. Four of them run the flaps. I'll be using a 5600mh ly ion battery to run the receiver. And two 2000 mh ni mh's to run the engines. Should not be a problem power starving. I'll be using a mpi voltage reg. For the receiver regulated to 6 volts. The engine batteries will be 4.8 volts. My only concern is y harnessing four servos together for the flaps. Patrick the teck from ARF Pro's told me I could use two receivers to run the flap Ch. But I haven't had the time to get together with him on how to do it.
 

coolgabsi

Super Mod & DEAL KING!
thats interesting.. Not that I have an input, but I would like to know, this sounds to be good information. :)
 

Tony

Staff member
It can be done, but I would never do it on my planes. the antennas are just way too close to each other and something could happen with the signal.

randy, he is wanting to use the two Rx's as a y to split the power consumption of the flap servos between two Rx's so he doesn't burn one up and lose the plane.

There are boards that are made for things like this to run many servos at one time. if it were me, I would be looking for these boards and not take the chance of running two Rx's. But thats just me lol.
 

RandyDSok

Well-Known Member
I understood completely what breeze400 was asking... and I know the DX7 can be setup for a 4 servo wing as stated in this webpage Spektrum DX7 Programming FAQ ... this is done with mixes and are still limited to just the 7ch that the radio supports. That setup doesn't provide what I believe he was looking for though... then 4 servos are tied together ( effectively one channel sort of ) which leaves only 3 other channels for throttle, elevator and rudder.

I've simply never seen or read where two receivers could be bound to one receiver model on the radio.

Your suggestion to use an add-on expander board makes better sense to me unless seperate sub-trimming is needed...
 

Tony

Staff member
I don't have a lot of experience with these boards, but I'm sure they have pots on them that you can use to set the subtrim. You would think they would have to lol. But with the size of servos that he is going to have to use, and the number of them, it's the only way I would want to go. And I would be running a "HELLA" BEC lol. either that, or a 5 cell Rx pack that is made for a big plane. but a BEC could be used with something like a 3000mah 2s setup for even more capacity.
 

breeze400

Spagetti Pilot
Tony, I'm using a 5600mah li ion battery for the receiver! 5600mah should do the trick! It is a receiver pack. With the above mentioned bec or voltage regulator down to 6 volts witch is what the servos require. Has far has a separate board to run the flaps point me in a direction so I can check it out! Lol. The battery choices I discussed with Patrick from ARF Pro's. He sells these planes on a daily bases. He should know about them. The receivers idea was just a suggestion. I have never heard of that so I thought I'd ask. I'll probably end up buying a dx8 and take care of this that way.
 

Tony

Staff member
Here you go, this is what you need. There is also a Channel Expander that you could use on there. But, the expander is made to take one channel and make it multiple. But there are huge limitations to this. I suggest the Matchbox.
 

breeze400

Spagetti Pilot
Just found it. Looks like a way to solve my problem all right lol I like what I read. Thank you thank you.
 

Keith

Member
I expect the 9x running er9x firmware could do what you want, it seems to do everthing else... I have not got into the mixes properly but I think you can mix 16 channels anyway you want... This guy is a bit boring and hard to understand but knows most of the ins and outs... I think it's lesson two he mixes flaps and ailerons....?

 
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breeze400

Spagetti Pilot
I expect the 9x running er9x firmware could do what you want, it seems to do everthing else... I have not got into the mixes properly but I think you can mix 16 channels anyway you want... This guy is a bit boring and hard to understand but knows most of the ins and outs... I think it's lesson two he mixes flaps and ailerons....?


Thanks Keith. Problem is if I wanted to buy a new transmitter, I would invest the $429.00 in a DX8 with the receiver, and a telemetry module. I'm trying not to do that. This Matchbox that Tony suggested sounds like it will do what I want. Mixing the four flap servos without overtaxing the volts coming out of the receiver. That way I do not have to use y harnesses to connect the servos together. They can just plug into the matchbox. Take a look and see. You can even use separate battery packs on the servos.

Horizon Hobby: MatchBox Servo Matching/Power System by JR (JRPA900)
 
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Keith

Member
Fair enough Breeze, I put the FrSky module in mine as well with telemetry. Has a quick range check which if correct gives me over 3klms... Looking at putting sliders in next... So if anyone is thinking of a new Tx this is a steal at under $60 (I paid $38 on special)....
 
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breeze400

Spagetti Pilot
I hear you Keith. I've got a little over 2 grand invested in this plane so far. I want everything to be perfect! So if I spend a little more on a tx it will be worth it in the piece of mind anyway lol.
 

breeze400

Spagetti Pilot
It's ok Tony like I said I already found it on horizons web sight. I ordered the twin pack. It was $30.00 cheaper than ordering two of them. It sounded like a great idea so I'm going to use one for the flaps and one for the elevators! Lol. Oh well, what's more money!!!
 
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