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Question regarding Crystals

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Old 02-22-2003, 03:52 AM
  #1  
borna
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Default Question regarding Crystals

I have a 6 channel futaba radio channel 14. The Transmitter doesn’t work and I took the crystal out of the transmitter and placed it on another Futaba radio which is channel 21. So basically I just removed the crystal from the bad transmitter and place it on another radio. I have tested it on the ground and everything seems to work fine. However someone told me I have to send it to factory for tuning? Is that true even though all channels seem to work properly?
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Old 02-22-2003, 03:58 AM
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Lynx
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Default Question regarding Crystals

What you did is technically illegal and will remain so until you have someone qualified check it. Only shops that are certified are legally able to change crystals. Though you'll get an earful from everyone, there's a lot of people that say it doesn't matter there's a lot that say it does. If you have the money to spare I'd suggest doing it anyways just so you don't have anyone yelling at you about crystal swapping. There's a slim chance you could be broadcasting too much RF energy outside of spectrum allowed for that channel.
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Old 02-22-2003, 03:58 AM
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JohnBuckner
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Default Question regarding Crystals

Yes its true, in the US it is aginst FCC regulation to change your own Tx crystals however you can change Rx crystals.

John
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Old 02-22-2003, 10:10 PM
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borna
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Default Question regarding Crystals

Well, I didn't know that is illegal. I better not mess around with it.
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Old 02-22-2003, 10:18 PM
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PigMan Buggerus
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Default Question regarding Crystals

Is it legal to change the whole Tx crystal module on a Futaba 9c?
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Old 02-22-2003, 11:35 PM
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Steve Lewin
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Default Question regarding Crystals

Yes.

Sec. 95.222 (R/C Rule 22) May I make any changes to my R/C station transmitter?
(a) You must not make or have anyone else make an internal
modification to your R/C transmitter.

(b) Internal modification does not include:
.....
(2) Changing plug-in modules which were certificated as part of your R/C transmitter.

HTH -Steve
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Old 02-22-2003, 11:37 PM
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strato911
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Default Question regarding Crystals

I am unfamiliar with the 9C, but if you are referring to swapping an entire RF module, yes, that is legal. Swapping the crystal within the RF module (if accessible) is illegal.
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Old 02-22-2003, 11:37 PM
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PigMan Buggerus
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Default Question regarding Crystals

Thanks for the info
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Old 02-23-2003, 02:40 AM
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bhanley
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Default Question regarding Crystals

lIts also interesting to note that the AMA specifically exculdes insurance coverage for those that swap crystals - they call it out in the member handbook as an unsafe practice and therefore the practictioner can be without insurance if the crystal swapping is identified for a given incident......
Bruce
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Old 02-23-2003, 04:00 AM
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Default Question regarding Crystals

Since the crystal on a transmitter is on the outside, is this still illegal?
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Old 02-23-2003, 05:00 PM
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ALbert.S
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Default Question regarding Crystals

This is an example of a loophole in the rules.The FCC says you cannot make any INTERNAL changes to your transmitter.So the manufacturers put the crystal on a socket and have it so it can be removed without opening the case and going inside.This promotes crystal sales and more equipment sales when the CHANGERS crash.Now the AMA has to make a rule preventing crystal changing with the threat of loss of insurance.Clubs now have to get members to become spies and enforcers so no one changes crystals.What a mess It would seem like the AMA should ask the FCC for a change in the wording. I suppose these people who are the CHANGERS do not belong to a club or the AMA. So the only thing They are concerned with is $$$$$$.I guess I don't understand why you would risk an expensive model to save a few bucks to get the change done legally and correctly with the crystals from the manufacturer
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Old 02-23-2003, 05:28 PM
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bhanley
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Default Question regarding Crystals

Albert S - using different manufacturers crystals is a minor part of the issue. The main point is that to be legal you have to send the transmitter back to the manufacturer to be retuned each time you change. Also, it turns out that there are a variety of reasons why you might want to freely (and often) change crystals, eg, have different planes on different freq, or use it as a way to handle crowding on a particular freq at your field, etc, etc... Note that as indicated above you can legally swap complete RF modules such as are used on the higher end JR radios. These are, of course, much more expensive than a simple set of crystals.
Bruce
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Old 02-23-2003, 05:31 PM
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strato911
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Default Question regarding Crystals

Originally posted by Geistware
Since the crystal on a transmitter is on the outside, is this still illegal?
From what I have read, it is illegal in North America.

Because the radios are sold around the world where users ARE allowed to change crystals legally, they are designed to provide users with access to the crystal. Radios sold in North America have the crystal glued in place, but typically they use so little glue that it doesn't hold.
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Old 02-23-2003, 06:39 PM
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Default Question regarding Crystals

A door or plug on the surface of a transmitter ,allowing access to a crystal WELL INSIDE the transmitter case is in NO WAY OUTSIDE the transmitter.
Time to put that one to rest
The crystal is well within the confines of the transmitter case.

Access is gained from the outside the crystal is INSIDE until you take it outside. Not even CLOSE to a loophole.

Some transmitters have been given type acceptance by agreeing to glue the access plug in place . The manufacturer is supposed to glue the door in place. This was to allow for sale in the US of transmitters designed for world market.
The FCC could in the future disallow the access. At that time the manufacturers would have to choose to design one radio for the largest market or different radios for different markets. It is a very competitive business and economy of scale would weigh heavily.
In the US the AMA is a determining factor as well as the FCC. The AMA fought for and won the 72 MHz freqs for RC at a time when we could well have lost the use of those freqs altogether. The AMA went to bat and took on a lot of the responsibility to avoid frequency conflict on 72 MHz. That is one reason they defend and enforce the standing rules. As the major underwriter of RC activity they have a vested interest in compliance with the rules they helped draft.
So far the problems have been few. It is an easy rule to comply with. The advantages of extra channels we have available compared to some other places make the AMA brokered plan an excellent bargain.



Modules made for a given transmitter type may be swapped legally. It is a very good idea to have these transmiiters checked out if you change modules often.
I have seen Futaba transmitters where frequent module changes have caused the solder joint on the pins to break down . This can lead to failure and intermittent operation.
This can happen on any transmitter (in any country) where modules are connected in a similar manner.



Lots of channels , plenty active enthusiastic flyers , good local hobby shops , inexpensive NITRO , Access to so many great fields ! Inexpesive insurance , Let FLY and obey the rules that keep it as good as it is here.
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Old 02-23-2003, 07:27 PM
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JohnBuckner
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Default Question regarding Crystals

*****AMEN*****


John
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Old 02-23-2003, 08:06 PM
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Default Question regarding Crystals

!!!!!!WOW!!!!!! Ladyflyer just to see your use of FACTS, INTELLIGENCE, AND GOOD OLD COMMON SENSE in one post! gives me hope that not all is lost in this hobby.
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Old 02-23-2003, 10:24 PM
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Default Question regarding Crystals

Ladyflyer
Party Time !

Ladyflyer
Registered: Jan 2002
Location: North of Canada


Unless you are in Alaska, their is not much north of Canada!
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Old 02-23-2003, 11:34 PM
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Default Question regarding Crystals

If I fly South from the nearest airport ,Canada is the first country I will enter. Canada is North of here as well as East . It IS closer to the South however .
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Old 02-24-2003, 04:30 AM
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Default logical thinker

Lots of channels , plenty active enthusiastic flyers , good local hobby shops , inexpensive NITRO , Access to so many great fields ! Inexpesive insurance , Let FLY and obey the rules that keep it as good as it is here.


LF:
There you go again with your clear, concise logic.
You belong working for NATO
Brian
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Old 02-24-2003, 10:36 AM
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Steve Lewin
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Default Question regarding Crystals

Originally posted by Ladyflyer
A door or plug on the surface of a transmitter ,allowing access to a crystal WELL INSIDE the transmitter case is in NO WAY OUTSIDE the transmitter.
Time to put that one to rest
The crystal is well within the confines of the transmitter case.

Access is gained from the outside the crystal is INSIDE until you take it outside. Not even CLOSE to a loophole.
Hi LF,
Even as a loophole the FCC seem to have closed it fairly firmly in :

Sec. 95.645 Control accessibility.
....
(b) An R/C transmitter which incorporates plug-in frequency
determining modules which are changed by the user must be type accepted with the modules. Each module must contain all of the frequency determining circuitry including the oscillator. Plug-in crystals are not considered modules and must not be accessible to the user.
--------------------------------------------------------

Hence the blob of glue. I don't think anyone can misunderstand the intention of those rules though of course some will always pick nits around the exact wording.

Still this is obviously a sore point with a lot of people. It's quite amusing to see this same discussion going on on several different forum sites at the same time (it's no wonder your patience gets a little strained from time to time ).

Steve
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Old 02-24-2003, 10:50 AM
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Default Question regarding Crystals

Originally posted by strato911
From what I have read, it is illegal in North America.

Because the radios are sold around the world where users ARE allowed to change crystals legally, they are designed to provide users with access to the crystal. Radios sold in North America have the crystal glued in place, but typically they use so little glue that it doesn't hold.
Stratto911,
I have 5 transmitters now and I think I can say I have seen at least 12-14 others.
All Futaba and not one had the XTAL glued in.
-----------------------------------------------------------------------------------Also I agree with JBruce about the crystal manufacture.
Some of the manufactures make then to a very tight tolerance and others are more then a 150 Hz off the frequency.
Sure would be nice o have an EE take one type of TX and change XTALS just to see what all the lab grade gear on the bench shows
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Old 02-24-2003, 09:18 PM
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Default Question regarding Crystals

Thank you Steve . Sometimes I think we are in danger of losing the language IYKWIM

Yes there are getting to be more and more transmitters where the cover is barely if at all glued in. The distributors are a prime offender here. They swap crystals ,supposedly retune and ship the radio without regluing. In fact the glue thing could well lead to a major change in transmitters sold in the US.
Again it only takes one event to get the attention of the FCC and yes they may over do the response .

Yes they are supposed to secure them and they still do ,not always however. It may be time to close that door to avoid confusing so many people :stupid:
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Old 02-26-2003, 06:00 PM
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Default Question regarding Crystals

Originally posted by Ladyflyer
If I fly South from the nearest airport ,Canada is the first country I will enter. Canada is North of here as well as East . It IS closer to the South however .
Your North of Canada then you say Canada is North of here and as well East.
How can you be North and South of Canada at the same time?
ANCHORAGE,AK
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Old 02-26-2003, 06:54 PM
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Phil Cole
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Default Question regarding Crystals

Sounds like it's something in the Detroit area. If Canada was to the west, then it would be near Niagara Falls.
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Old 02-26-2003, 09:48 PM
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Quite a few miles North of that . On the shores of Lake Huron

Very good Phil !
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