Buying models- are the transmitters always on different frequencies

[Malcolm Amiss]

As a total novice, can someone tell me if I were to buy 2 identical models at the same time from the same place, would the frequencies of the transmitter be different?

[Matt Carlton]

Generally speaking you would only get a transmitter with each model if you buy a ready to fly package. Most of those, and indeed, most transmitters commonly available are on 2.4Ghz and rely on individually 'binding' to the receiver so they are not on any specific or fixed frequency as is the case with 35MHz. So, in reality, the question is rather moot as the technology has moved on since the days of fixed frequencies and crystals.

[Simon Chaddock]

Malcolm

Put another way as long as the models are identical and from the same manufacturer either of the provided transmitters will work with either model.

However to get it to work at all you have to 'bind' the receiver to the transmitter. The transmitter will then only 'talk' to that receiver.

There is nothing stopping you subsequently binding it to your other plane but it is unlikely to talk to the first one.

In principle a transmitter can only control one plane at a time.

Be aware that each transmitter manufacturer uses their own signal 'protocol' so only a receiver designed for that protocol can be bound to that transmitter.

Edited By Simon Chaddock on 22/01/2021 17:37:17

[Allan Bennett]

Posted by Simon Chaddock on 22/01/2021 17:36:46:

.... There is nothing stopping you subsequently binding it to your other plane but it is unlikely to talk to the first one.

In principle a transmitter can only control one plane at a time. ....

That's certainly not true of all 2.4GHz radio systems -- I can bind two or more receivers to a single model channel on my FrSky transmitter, and it will control both of them at the same time, if they're both powered up.

But in practice that danger (or function, if you do it deliberately) only applies to your own models: If you haven't 'bound' a receiver to your transmitter, as is the case with a receiver in someone else's model, it won't control that model.  Just make sure you don't bind two of your own models to the same model channel in your receiver, and then inadvertently leave one powered up while you're flying the other -- it has been done 

Edited By Allan Bennett on 23/01/2021 20:26:28

[Frank Skilbeck]

Malcolm on 2.4 GHz all transmitters work by moving around the frequency (frequency hopping) but each transmitter has it's own unique code that the receiver learns when it is bound/linked to the transmitter so it will only work with that transmitter, some systems which have model memories also give each model memory a unique code so the receiver will then only work with the model memory it has been linked with.

Different manufactures use different 2.4 GHz chips and also data transmission so transmitters will only work with receivers specifically designed to work with them.

[cymaz]

When you bind a receiver (RX) to a transmitter (TX)they lock together. No other Tx will communicate to that Rx

For example your Tx has 6 model memory. You need to bind your Tx to each of the 6 Rxs....one in each plane.

Your individual plane menus ( reverse servos, throw rates, switches) are set into the model memory on the Tx. For example, Model 1 has reversed servos on Rudder and aileron, 50% throws and an undercarriage servo on a switch. Model 2 has reversed servos on elevator and throttle and 10% throws and a fixed undercarriage but flaps.

When you switch on the Tx ( which you always do first), you would select either Model 1 or 2. Once that is done turn on the model you intend to use, for example Model 2 . As the Tx and Rx will only receive and send data to each other no one else's model will be working with your Tx input controls. This is ok for 2.4 ghz radios, 35 MHz radios are an entirely different subject, which we can discuss later, should the need arise.

However, while your Tx is turned on and you accidentally turn on Model 1 as well, that might also work.....not a good situation

Edited By cymaz on 24/01/2021 07:38:16

[cymaz]

Butter fingers

Edited By cymaz on 24/01/2021 07:34:51

[Engine Doctor]

I'm not sure about other systems but my. FrSky tx can operate as many rxs as needed at the same time once they have been bound . I use two rxs to fly a large zagi type model , one in the model and a second In the take off dolly to steer and release it from the model once airborne. Using multiple rxs is only limited by the number of channels you have or are needed .

Can a Spectrum set up that uses model ID be used the same  way ? 

Edited By Engine Doctor on 24/01/2021 11:18:17

[Dickw]

Most RC 2.4 systems can operate multiple receivers at the same time, including Spektrum. A second receiver linked to the scoring system is a requirement of the competitions I have been flyin in for many years, and all systems seem to manage it one way or another.

Dick

[BackinBlack]

Knowing the make and models that the OP is asking about would help in giving a definitive answer.

[cymaz]

Posted by Engine Doctor on 24/01/2021 11:16:17:

I'm not sure about other systems but my. FrSky tx can operate as many rxs as needed at the same time once they have been bound . I use two rxs to fly a large zagi type model , one in the model and a second In the take off dolly to steer and release it from the model once airborne. Using multiple rxs is only limited by the number of channels you have or are needed .

Can a Spectrum set up that uses model ID be used the same way ?

Edited By Engine Doctor on 24/01/2021 11:18:17

I have a model with 2 separate Rx systems . Redundancy if something should go wrong. I took it from the OP that it seemed he was going to buy rtf models.

[Allan Bennett]

Agreed, cymaz. But he didn't specifically say so. If he took advice from the model shop, he might have got two bnf models with a single transmitter. Anyway, it's good to publicise the options/pitfalls.