Recievers and transmitters
04-26-2004, 08:44 PM
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Recievers and transmitters
Can you use ANY transmitter with ANY reciever as long as they are both either AM or FM, and on the same channel?
Weskel
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04-26-2004, 10:55 PM
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RE: Recievers and transmitters
The short answer is, "no"...or perhaps more correctly "maybe". I'm a little fuzzy on the theory behind it, but I'll give it a go....In North America (at least)Futaba shifts it's frequency one way from the carrier frequency it's on and JR/Airtronics shift the other way(I've forgotten which shifts which way, but I'm sure someone will jump in and refresh my memory). The net result is that Futaba and JR/Airtronics don't talk to each other... not sure about Hitec...
Having said that, some Xmtrs..Airtronics RD series/Hitec Eclipse/Multiplex(?)...let you select which "shift" you transmit and some (Hitec I think) receivers have a jumper that you pull out and turn around to select which "shift" it will receive.
I'm sure somewhere, someone far more knowledgeable about radio theory is cringing as they read this, but that's the basics...hope that helps....
Edit:Of course AM and FM don't mix and channels have to match!
Having said that, some Xmtrs..Airtronics RD series/Hitec Eclipse/Multiplex(?)...let you select which "shift" you transmit and some (Hitec I think) receivers have a jumper that you pull out and turn around to select which "shift" it will receive.
I'm sure somewhere, someone far more knowledgeable about radio theory is cringing as they read this, but that's the basics...hope that helps....
Edit:Of course AM and FM don't mix and channels have to match!
04-27-2004, 11:01 AM
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RE: Recievers and transmitters
There's more to it than just the AM or FM modulation. There's also the encoding PPM and PCM. These two encodings are not compatable, and a PPM receiver will not work with a PCM transmitter and vice-versa. There are also several flavors of PCM. So the answer to your rather sweeping question is "definitely not". However, a lot of manufacturers have gone to a great deal of trouble to be as compatable as possible. Many of the more expensive transmitters can be programmed to do multiple types of output (of course only one type of output at one time). And some receivers can be jumpered to work in different modes.
04-27-2004, 11:09 AM
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RE: Recievers and transmitters
CP140 is right on, when talking about FM, PPM.
Wisdom-Seeker is right on about PCM, as far as I know, no one's PCM is compatiable with anyone else's PCM.
As CP140 said, there are some RX's that can be switched. In addtion, there are even some RX's that will "auto detect". And some RX's can be ordered in either version, Hitec, FMA, GWS and others make RX's in both versions.
And, some TX's can do either version of FM, sometimes it requires a specific module.
Oh, one funny thing, once you get past the "shift" direction of the FM signal, different companies assign different flight controls to different channel numbers. So if you switch transmitters, you sometimes have to unplug and re-arrange all the servo connections. (and, on a not-quite-related note, different companies servos are often reversed from each other. If you pull a futaba servo and drop in a hitec, for example, you will usually have to hit the reverse switch on that channel).
I haven't messed around with AM in too many years, so I haven't a clue anymore about that one
.
Wisdom-Seeker is right on about PCM, as far as I know, no one's PCM is compatiable with anyone else's PCM.
As CP140 said, there are some RX's that can be switched. In addtion, there are even some RX's that will "auto detect". And some RX's can be ordered in either version, Hitec, FMA, GWS and others make RX's in both versions.
And, some TX's can do either version of FM, sometimes it requires a specific module.
Oh, one funny thing, once you get past the "shift" direction of the FM signal, different companies assign different flight controls to different channel numbers. So if you switch transmitters, you sometimes have to unplug and re-arrange all the servo connections. (and, on a not-quite-related note, different companies servos are often reversed from each other. If you pull a futaba servo and drop in a hitec, for example, you will usually have to hit the reverse switch on that channel).
I haven't messed around with AM in too many years, so I haven't a clue anymore about that one
.
04-27-2004, 06:33 PM
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RE: Recievers and transmitters
PCM are not interchangeable.
FM/PPM: In general, Futaba and most of Hitec are interchangeable (negative shift), also JR and Airtronics (positive shift).
There are some receivers that can decode both Positive and Negative shift, like selected models of Hitec and FMA. Also some TX are "Shift Selectable", so can work with any PPM RX.
FM/PPM: In general, Futaba and most of Hitec are interchangeable (negative shift), also JR and Airtronics (positive shift).
There are some receivers that can decode both Positive and Negative shift, like selected models of Hitec and FMA. Also some TX are "Shift Selectable", so can work with any PPM RX.
