transmiter and the necessary crystal?

I see many radios up for auction. The channel is never mentioned, is it possible to use any crystal to change the transmiter channel to the one you want?

No. The FCC says you can't change the transmitter crystal. The receiver crystal can be changed though.

In theory, it is possible to change any channel to any other in the same band. In reality, however, it's wise to not go farther than 3-4 channels from the original frequency, unless you have the system retuned.

The FCC does frown on transmitter frequency changing, unless you have the proper license. However, it's done all the time by modelers. Crystal sets are easily purchased at your LHS. Dr.1 Driver "There's a Hun in the sun!"

It would be foolish to do that yourself, but it does not cost very much to send your radio in to the mfgr. service center and have them change the frequency crystal and then retune the radio. I think if you send in a Hitec radio to Hitec, for instance, they check up is free and they only charge you for shipping and for any repairs needed (if necessary). In fact, I would suggest that it would be foolish to buy a used radio and NOT send it in to the service center for a check up and tuning even if your not changing the frequency.

MJC

What is the proper license to which you refer?

The common understanding is that you can go up or down 4 channels without retuning, otherwise you need help. The crystal just sticks right out at you, in my transmitters, and I don't believe a red light would go on in Washington if I did it. If you do it, I'll not tell.

Don't you need some type of Technician license to legally alter a transmitted frequency? Dr.1 Driver "There's a Hun in the sun!"

Usually, the person forgets to put the channel in the description. If I'm interested, I ping them via email for the channel.

Take into account that it costs $15-25 to get a tx freq changed.

David

One license is the General Radiotelephone. Interestingly, I asked Hitec if they would sell me crystals since I have that license and was told NO ! ! ! ! So even tho I'm licensed and qualified - being an amateur radio operator for 27 years - being told no kinda irks me.

David

There used to be a third through first class commercial license with various endorsments. ie. Radar, aviation radio etc. They did away with that.

The various engineers got together and created a pseudo license to protect their jobs. One could be a station enginner of a radio or TV station with nothing required except the breath in your body and someone to hire you and bestow the title of "Chief Engineer" upon you.

I have not done any kind of research as to what is required these days. I thought someone would jump in here and tell us. Since no one has, I am off to the FCC regs to see if a human with nothing more that his fingers, and the desire to change a crystal is allowed.

In the licence days, for example, you could change a crystal in a CB radio. That same radio had to be repaired by a holder of at least a second class commercial license.

As changing a crystal requires no adjustment to the transmitter, I question why it would be forbidden to the average modeler. Let me take a bit of time, and I will get back with the newly found wisdom.

Any one else have specific knowledge?

I believe you merely need to be a technically competent person :-)]

Technical competency aside, checking the results after swapping a transmitter crystal requires a little more in test equipment than a "wet finger and a screwdriver".

Mike

I know that this works different in the USA (as I understand the radios there can't have an easily ascessed crystal) but in most of the rest of the world, the crystals are easy to remove with nothing but the fingers, and the users are reccomended to buy a pair of extra crystals, incase someone else is using their freq at the field, it works for the rest of the world, it should work just fine in the US too, the only difference is that we use different band (35MHz vs 70MHz).

The 70MHz band is a bit wider then our 35MHz band, but that wouldn't really be an issue, since there is lot of radio equipment covering wider bands than that, without need for retuning the blender freq when you tune from one bandedge to another

This leads me to belive that the real reason it is not allowed for anyone to change crystals in the US is in case of an accident, you need to have someone to sue...

Could it be that simple?

I can tell you right now no licience is required! I think the radio control section says you must be certified, but does not say who does the certification, the manufacture perhaps.

Hitech does not sell tranmitter crystals for 72 Mhz FM sets, but they will sell them for the AM sets and 75 Mhz FM. Intrestingly the rule's are the same for both, but the Spectra module doesn't work on the the sets that they make the crystals for. Its all a hoax based on an intentional missintrepretation the CFR.

Nothing is required to change any thing you feel like changing in an R/C transmitter. You maintain the radio with absolutely no licenses of any kind, not even a box of crackerjack in hand, is required.

On the other hand, you cannot make any design changes etc. that would violate the type acceptance.

Swapping modules from one manufacturer in to another, for example, while they may work is technically not permitted. As the type acceptance did not include these modifications.

We are allowed to change crystals in the US, despite old wives tales to the contrary.

Under the old laws that is true, when they did away with the various classes of commercial licences it all changed.

Today you only need a license to work on aviation, or shipboard communications.

Think anythng where a failure puts passengers in danger.