Receiver/Transmitter Question

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Michael Chandler
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Receiver/Transmitter Question

Post by Michael Chandler »

Hi guys,

I am a new builder but have been registered to your site for several years!

My question is:
Can I use a two channel transmitter to operate a four chancel receiver?

I own a two channel transmitter, details of which can be found here:
http://www.rccarsandtrucks.co.uk/503_1_13386.html

The transmitter comes with a receiver that's too big to fit into my design unless I remove the case, so I'd like to use a smaller receiver, namely the Futaba R114F.

As I'm sure you are aware the R114F has four output channels. My design only requires two (no moving weaponry) so the transmitter suits my needs.

Back to the question, would the R114F be compatible provided the crystals match and the servos are plugged into the correct output channels, or am I walking into some kind of fiendish trap for the unwary?

Thanking you in advance :wink:
Andrew_Hibberd
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Post by Andrew_Hibberd »

Yes.....

The first two channels should be compatable. I have used a 5 channel rx with a 4 channel tx.
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Remote-Controlled Dave
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Post by Remote-Controlled Dave »

That's fine, should work as long as everything you say matches.

What took you so long to start? lol
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Simon Windisch
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Post by Simon Windisch »

As far as I am aware the architecture allows for eight channels, and the the transmitter sends each channel's signal prefixed by that channel number so you can use a two channel transmitter with a four, six or eight channel receiver and it won't matter, but as discussed elsewhere on this forum, it's best to stick to the same manufacturer of transmitter and receiver, as they're not all 100% compatible.

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BeligerAnt
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Post by BeligerAnt »

Simon, the standard systems aren't that sophisticated! Maybe some of the fancy PCM ones are, I don't know.

The basic systems use a 20ms "frame" with a 2ms "slot" for each channel and a 4ms "frame sync" pulse. Each slot contains one channel pulse, from 1ms to 2ms long. The position of a pulse relative to the sync pulse defines which channel it applies to.

It is possible to send less than 8 channel pulses, as the sync pulse resets the receiver logic back to channel 1 each time.

So long as you use channels 1 and 2 of a 4-channel receiver, they should work fine with a 2-channel tx. BTW, the old Hitec Ranger 3-ch txs actually had an eight-channel chip in them, just the unused channel inputs were fixed to 0V!
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josh
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Post by josh »

jst make sure that ur tx is 40 mhz FM and u buy a 40 meg FM receiver (thas prob the only frequency u could get with an r114 coz they do only 35 and 40 i fink {but i duno ive never used 1 :P})
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Post by Remote-Controlled Dave »

Gary, thats an amazing bit of writing there! I stick to "if it plugs in and works, it can fight" logic!
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paul
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Post by paul »

Dave26 wrote:Gary, thats an amazing bit of writing there! I stick to "if it plugs in and works, it can fight" logic!
nah he just uses big spaces to make it look better (as do i...)

and i agree with simon, it isnt just the fancy ones, i got a transmiter and reciver that only work on one channel, it may be broken but its been like that since i got it... asnnd to be honest its really annoying :evil:
Michael Chandler
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Post by Michael Chandler »

Thanks guys, much apreciated

Dave26 - Its taken me so long to start because of a lack of time/money/equipment, which I'm sure all of you can empathise with. I have though been doing my research, including spying on you guys for the last few months!
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Post by josh »

:o
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