NCLights

Hey guys, I know changing the crystal is illegal, but say you open up the transmitter and then close it...Does this count, since the crystal is technically taken out, but then put back in...Thanks

aksmithrc

My Feedback: (2)

What is ILLEGAL is changing the transmitter from ONE channel (frequency) to a DIFFERENT channel (frequency).
I am wondering why would you even take a crystal out just to re-insert it anyway; anyway, it is not illegal, but, why?

NCLights

I thought I heard something rattling around inside the transmitter, I realized it was just the battery small circuit panel, and then realized I had also taken out the crystal because it was connected to the back of the transmitter.

JohnBuckner

My Feedback: (1)

In that case there is no problem, just make sure it is carefully reseated and just for the record crystals have no polarity and it does not matter it it goes back in with the pins reversed.

John

Lynx

If you want to get purely technical, removing the crystal and then re-inserting it is still illegal. But that's jut being plain stupid about things.

strato911

My research into the FCC regulations would agree with Lynx...

IBRC

I always thought this sounded confusing. A frequency can have different channels correct? That is why they make different crystals so you can change your channel if someone else is using the same channel so there will be not interference. I'm guessing that you can't change your frequency of a radio from 72 to 75 or vice versa or a 27 to 75 etc., but you can change a 75mhz radio from channel 65 to channel 70? I could be wrong, I'm still trying to figure it out. We wouldn't want to do anything illegal, that is why we always drive the speed limit

Mike Ledbetter

I believe it is common and recommended practice to remove the Tx crystal when using the Tx to operate a computer simulator.

JohnBuckner

My Feedback: (1)

IBRC

A band is the entire spectrum of the frequencys within that band (Most commonly used is 72Mhz aircraft only band). In the US there are fifty frequencys within that band that we can use. Each frequency is assigned a channel number to simplify things, any given frequency will always be the same channel number.

What the gentleman you quoted was saying In primarily North America It is illegal to change your own Tx crystal yourself without sending in for a retune. In the case of a modern module type radio or a sythesized Tx then yes you can chane the TX channel/frequency by switching a single freqency module for another on a differant channel/frequency or changing a sythesized transmitter by a program process. Also within this band half way between each of our channels there are are as many commercial/industrial frequencys and these user's are licensed and 'paid' user's that are FCC listed as 'primary user' and we will not be allowed to step on their toes as unlicensed, unpaid 'secondary' users This is why our old wideband radios became illegal to use many years ago when this band was opened up for commercial use and there is very little space between them and us.


Now be aware it is not illegal for a user to change a Rx crystal himself to effect a channel/frequency change himself. this is legal and requires no retunning.

Hope this clarifies things a bit

John

IBRC

Thanks John, I understand it, I think. The bands are like 27, 72 and 75 and the frequencies of those bands would be the different channels? I have a Futaba that came with a ch. 65 crystal set and the stickers on the tx and rx have the 65.blah blah frequency on them. Is the tx and rx tuned specifically for that channel, maybe for optimum use? Could I replace those xtals with a ch. 70 which is also in the 75mhz band.

strato911

The Tx's are tuned to the channel they are sold on, and the Rx's are tuned for the center of the band, with the exception of Futaba, who tunes the Rx's for either the upper or lower half of the 72Mhz band.

strato911

Here's a table to help explain the different bands (save it to your harddrive), and the channel / frequency corelation used in North America.



The 50Mhz and 53Mhz frequency bands are only legal to use if you have a Ham radio licence.