Need Radio Explanation on 27MHz

[Transom2]

Excuse my ignorance, but I'm not sure what the radio descriptions mean.
If I buy a 27MHz radio with 4 channels, will that radio then come with
Channels: A1-26.995MHz; A2-27.045MHz; A3-27.095MHz and A4-27.145MHz? Also, if a r/c boat indicates that it is simply 27 MHz what frequency is this
in actuality in the A1 to A6 range? Please recommend what radio(s)
I should look at and explain the frequency.....THANK YOU!

[BoatDoc]

the four channels are the available controls. throttle, steering etc... 27mhz is the range it operates in. from there you would select your specific frequency. there are also 75mhz, 72mhz and others. some for surface use, others for air. if you are looking into buying a radio, look at what you need. if you are putting together a standard boat, all you need is throttle and steering (a 2 channel). lots of scale guys get 4 or more. some nitro/gassers use 3 channels so they can have a servo control the fuel mixture. if you see an RTR boat and it says "27mhz" that means it is one of the 6 27mhz freq's that are commonly used. tell us what you plan on doing, and we'll try to steer you towards the right radio. here's a tip...look at the big tower catalog in the radio section, they give a pretty decent explanation of radio gear.

[CG Bob]

Channel has two meanings inour hobby. First, "channel" means the frequency you're operating on. Like BoatDoc said there are 6 differnt channels (frequencies) in the 27mHz band, designated A1 thru A6. Channel A1 has a frequency of 26.995 mHz. Think of your favorite radio station call sign and the frequency (radio dial setting). WMJI is at 105.7 FM like A1 is 26.995.

The second "channel" refers to the number of control sticks, knobs, and switches on the transmitter. In theory, one channel controls one servo or electronic speed control. In practice, some people use special "Y-harnesses" to plug two servos into one channel plug on the receiver. SInce most 4-channel radios are set up for airplanes, the receiver will have the 4 channels listed as: Channel 1 - aileron (generally used for boat rudder); Channel 2 - elevator (can beused for starboard motor/esc or some switching device for horns, lights, etc); Channel 3 - throttle (generaly used for single motor esc, or port motor esc in twin screw boats); Channel 4 -airplane rudder (generaly used for bow thrusters, sub ballast tank, or switching devices). The control sticks for the channels are: Channel 1 - right stick moves left & right; Channel 2 - right stick moves up & down; Channel 3 - left stick moves up & down: Channel 4 - left stick moves left & right.

[guver]

I have wondere this for a while, I see that "channel" 1 is a certain freq. But what is the difference or the definition of the other "channels" you mentioned?

Like a 6 channel radio on a specific frequency, what is the difference and how does the radio know the difference between those "channels"

are they all minute different frequencies? within one freq? like 27.095 can have 4 channels.

[davec-nitro-rs4]

Whenever I think about any question relating to radios, I go to www.futaba.com. Their site has TONS of info.

How channels within a frequency work...

http://www.futaba-rc.com/faq/faq-receivers.html

[Transom2]

Thank you for the insight on the 27MHz radios. If I purchase a 27MHz radio will it automatically come with all six 27MHz frequencies beginning at 26.995 and going to 27.225? Also, I am going to the Futaba.com site.
Again, THANK YOU for your valuable assistance. I really appreciate it.

[davec-nitro-rs4]

A crystal based frequency radio USUALLY only comes with one set for one frequency. If you want to have more frequencies on hand to avoid conflict with another user, you will prolly have to buy additional crystals for the radio and receiver.

A synthesized frequency radio and reciever costs more, but eliminated the fixed freq crystals, allowing you to "tune" to an open frequency, as needed. It is the next step up from a stock type RTR radio system. They can be purchased used fairly cheaply right now, as many racers as moving up to DSM/Spektrum radio systems, and they are dumping their old synth radios.

[guver]

No, it'll be only one freq.

[guver]

Whenever I think about any question relating to radios, I go to www.futaba.com. Their site has TONS of info.

How channels within a frequency work...

http://www.futaba-rc.com/faq/faq-receivers.html

Thanks, the links explained "band" very well and I think I get "pulse" but still can't quite understand what a channel within a frequency is. I've only been wondering for 3 years,,, ;)

[Ron Olson]

Figure just like a TV or radio, the same thing as far as frequencies go. An FM radio station broadcasts in stereo so think of that as a 2-channel R/C system. The reciever on an R/C system is like the radio station and your (for instance) car radio. The sound coming through your speakers is split into left and right channels. What you have in your R/C is basically "music", a lousy beat and hard to dance to! :D The reciever interprets where the signal has to go.
The 27 Mhz band is also shared with some CB radios as they use the same band. Our channel 3 is 3-A on CB's, an illegal frequency for them. If you had an old crystal CB radio, you could actually put that crystal in a CB and broadcast on it.

[guver]

Ok, I think I have it. How many channels can be on one 27 mHZ frequecy?
What keeps them seperate. I know sounds like dumb questions,,,

[CG Bob]

You can have many different (control) channels on radio frequency. Using Ron's "music" analogy, harmonics are what separate the different control channels. Let's assume that control channel 1 is based on an "C chord" (piano notes A, C, & E); note "C" is that servo at rest; playing both the "C" & "E" notes causes the servo to move one way; playing the "C" & "G" notes causes the servo to move the other way. Each control channel is on a separate harmonic (modulation of the frequency or the amplitude) of the base frequency.