egrave

If you have a Radio that has channel 48 and a Rec. with channel 48 how many channels can you go up or down before you run in to a problem.

RCKen

My Feedback: (9)

What do you mean by "go up or down before you run in to a problem"? Are you talking about changing the radio's channel? Or are you talking about using other radios on other channels?

Ken

egrave

Yes I am talking about changing crystals in the TX and RX

Scar

My Feedback: (3)

The answer requires some more information:

The Transmitter manufacturer?
The Receiver manufacturer?
Is the "Module" externally replaceable in the transmitter? Or is it determined by an internal tuned circuit with a crystal?

With these answers, a better response can be made.

Good luck,
Dave Olson

RCKen

My Feedback: (9)

You can change the crystals in the receiver to any of the aircraft channels, 11-60. You cannot legally change the crystals in the transmitter in the United States. FCC regulations state that the transmitter must be re-tuned when the frequency is changed. To do that you would have to send the transmitter back to the manufacturer or an authorized service center to have the channel changed.

Ken

egrave

Some one told me that you can change the crystals in a TX and RX with out any problem I though that they had to be tune to each other or your airplane would not fly right.

RCKen

My Feedback: (9)

Oh yes, you can take the crystal out of the transmitter and put a new one in. What I am saying is that it is not legal to do that in the United States. This is part of the FCC codes and regulations. I wasn't saying that it's not possible to do it, I was saying that it's not legal to do it.

You are correct in that the receiver and the transmitter must be on the same channel to work. Might I ask why you need to change the channel on your radio? I know that many will change the receiver so that it is on the same channel as the transmitter, but it's not too often that people will change the transmitter channel.

Ken

egrave

Ken Someone told me that you could change the crystals in any TX and RX and not have a problem. The original crystal was 48 in the TX and RX and he says you can put a crystral 16 in the TX and RX with out haveing any problem

RCKen

My Feedback: (9)

As I said before. Yes you can change the crystal in your transmitter, BUT IT IS AGAINST THE LAW FOR YOU TO DO SO. I'm not saying that it's not possible to do it, I am saying that legally you have to send it in to get it changed.

Ken

bhole74

Would you like to be this guys Guinea Pig? Lose your plane if it doesn't work? How about others that may be on the recieveing end? Like Ken said, you can switch them, but it is against FCC rules and regs. Most rules are made for a reason. I guess there is only one way to find out for sure.[]

Rodney

Another bad thing can happen if you change the transmitter crystal without having it checked out by an authorized service. It might appear to work well (your plane responds to the proper commands) but; you may be interfering with others unknowingly. Doing the crystal swap without certification also nullifiys your insurance coverage should you become involved in a problem.

Paternguy

My Feedback: (1)

I remember several years ago, probably not to long after the frequency change in 91, there was an article in one the magazines that said you should not go more than 2 channels up or down without retuning the circuitry.

Also most manufacturers sell their receivers in either a high or low range. That being said I don't think it would be a good idea to go from channel 48 (high range) to channel 16 (low range). If you still decide to follow the advice of the local "Field Professor", let us know how many bags you needed to pick up all the pieces. LOL

BuzzBomber

My Feedback: (4)

Define "most manufacturers". Unless I'm mistaken, Futaba is the only radio manufacturer currently employing this practice, at least in the US market. I have never run into that issue with my Hitec and JR radio equipment. +/- shift is another story, though...

Scar

My Feedback: (3)

Buzzbomber is correct, the only manufacturer I see offering Receivers in two "ranges" is Futaba.

One thing that Egrave could clarify is, does the transmitter in question have a replaceable module, or is it really a crystal. Modules can be changed, if the transmitter is built that way, all the tuned circuitry stays with the module.

However, he has not offered any specific information.

Dave Olson

Paternguy

My Feedback: (1)

I believe the new Hitec Optic 6 is being sold this way as well. According to the review in the June 2005 MA.

That being said I still think its a bad idea based on the original 1991 info that recommended no more than a 2 frequency derivation. I would definitely do my own research on it before attempting it with one of my birds.