Jackster00

I'm thinking of buying a Futaba 7C TX from a fellow club member. It's NIB. It's channel # is different from the one I need for all my RX's. Can I simply buy a crystal for the channel I need and put it in this transmitter and be OK?

Jackster

pettit

My Feedback: (23)

No, you have to buy a plug-in module.

Crystal changing in transmitters is a violation of FCC rules. Only manufacturers and certified repair stations can do it.

If an individual changes a transmitter crystal, it may not be exactly on frequency also. Your flying buddies may not like that too much if you shoot them down.

Plus you have to constantly watch out for the "Crystal Police"!

MerlinL14

"It is not illegal, nor is the FCC an enforcement body by definition -- they administer the spectrum".

pettit

My Feedback: (23)

On the contrary, Yes it is, and yes they are.

But you probably would never get caught.

Until you happen to shoot another plane down because your transmitter is a bit off frequency

tuwood

huh?
Then why is there an easy to swap crystal on the back of my 7C that I pull out and replace for some different planes I have?

I'll admit I'm not familiar with the FCC rules at hand here, but you make it sound like you have to go into your transmitter and perform surgery with a high margin for error. I simply have 3 different futaba crystals on 3 different channels and swap out the channel I happen to be running. I'm not quite sure how that's dangerous to my flying buddies.

Tony

BarracudaHockey

My Feedback: (11)

Because if you don't have the equipment to check the output you have no idea if the transmitter is in tune, you've violated type acceptance and risk forfeiting any insurance coverage you have should a serious accident occur with any sort of investigation involved.

Or he could spend 15 or 20 dollars, get it done correctly and tuned and not worry about it.

tuwood

Well, this is good info. I guess as a relative newbie when I get a radio that has an easily accessible swapable crystal plug on the back, that it's there for me to swap them out if necessary. They should hard wire them internally if you're not supposed to change them.

Fortunately I'm always on the stock crystal for my glow planes, so I'm good there. I just have a couple foamies that I fly around my house that I have to swap crystals for.

MerlinL14

Having read the appropriate chapters (yes thats pretty sad) I have seen no where that it say it is illegal! I have seen recommendations and exclusions to Freq band changes but nothing that states you can't change the channel within that Freq band.

§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:

(1) Repair or servicing of an R/C station transmitter (see R/C Rule 21, §95.221); or

(2) Changing plug-in modules which were certificated as part of your R/C transmitter.

(c) You must not operate an R/C transmitter which has been modified by anyone in any way, including modification to operate on unauthorized frequencies or with illegal power. (See R/C Rules 9 and 10, §§95.209 and 95.210.)

[48 FR 24894, June 3, 1983, as amended at 63 FR 36610, July 7, 1998]

As I see it sub para (2) refers to the crystal as a plug in module!!

§95.209 (R/C Rule 9) What equipment may I use at my R/C station?

(a) Your R/C station may transmit only with:

(1) An FCC certificated R/C transmitter (certificated means the FCC has determined that certain radio equipment is capable of meeting recommended standards for operation);

Empisis to the text has been added by me.
As stated anything I see as recommended is clased as a rule not a law.

Now all this is my interpritation of what I have read. Maybe over the years someone elses interpritation has been mis-represented, and is now just 'believed' to be fact!!

Without starting a war and after reading the 'black and white' published paper, what do you recon??
Here is a link to the FCC document.
The relevent chapter is: TITLE 47—TELECOMMUNICATION COMMISSION (CONTINUED)
PART 95—PERSONAL RADIO SERVICES.
http://www.fcc.gov/Bureaus/Engineeri...97/47cfr95.pdf

tuwood

Good info Merlin.
I interpret that as it's ok to swap your crystal out.

I'd also be curious how the Synthesized Transmitter Module available for the 9C falls into this discussion.
Features: Eliminates selecting and installing transmitter crystals in the 9C or 9C Super transmitters
Is it really any different than having a box of crystals to swap out?

BarracudaHockey

My Feedback: (11)

Modules do not fall under the rule as the entire tunable RF section is swapped out. You can change the module, you can use a synth module, you cant change a crystal.

TITLE 47—TELECOMMUNICATION COMMISSION (CONTINUED)
PART 95—PERSONAL RADIO SERVICES

Subpart E—Technical Regulations
Sec. 95.645 Control accessibility.
(a) No control, switch or other type of adjustment which, when
manipulated, can result in a violation of the rules shall be accessible
from the transmitter operating panel or from exterior of the transmitter
enclosure.
(b) An R/C transmitter which incorporates plug-in frequency
determining modules which are changed by the user must be certificated
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.

MerlinL14

tuwood, No its is not OK to change your crystal in the US. Semantics aside chapter 95.645(b) specifically excludes plug in crystals under the definition of "modules". What you must understand is that it is not illegal it is just not approved by the FCC. The FCC under this recommendation must also apply through the federal justice system to bring a prosicution and have no direct powers to administer a fine or other penalty to an abuser. Which takes us back to post #3 I made earlier. Your flying buddies would be the first to jump on your case if you caused personal or property damage due to a crash knowing you changed your crystal in the Tx yourself.
barracudahockey , I was getting there just not as quick as you on the keyboard .

tuwood

I guess this is the part I'm having a tough time with is the fact that the crystals are easily swapped out and on my Futaba 7C. It's as if it's meant to be swapped out because it's so accessible. The rule you quote above reads like Futaba's violating the regulation because Plug-in crystals are not
considered modules and must not be accessible to the user. But, my crystal is accessible. [sm=spinnyeyes.gif]

I did just break out the Futaba manual and they actually cover this topic.
In North America it is against FCC regulation to change the crystal within the transmitter to a different
channel. All such transmitter crystal changes must be performed by a certified radio technician. Failure to properly tune
a system to its new channel may result in decreased range and may also result in interference to other types of frequency
users on adjoining channels. Doing so also voids your AMA insurance.

Here's some info I found on Futaba's web page also:
For a unit with crystals: We CANNOT recommend changing crystals to a different frequency. Changing the crystal on your transmitter is illegal unless you have the proper license. The FCC has established guidelines for the modeler's safety and for the safety of spectators. For safety and FCC reasons we must request that both TX and RX be sent to the service center to ensure proper crystal change and retuning to the new frequency. Crystal based radios cannot be converted to another band without parts replacement, and may not be able to be converted at all. Certain radios can be converted, for example, from 72 to 75MHz. Please contact the service center for any other conversions.

I also called Futaba support to ask their opinion and he said technically it is against FCC rules to change your TX crystal but the only time you really see anybody get in trouble for it is when they try to modify a crystal inside a module. But, it is a violation either way.

So Jackster, in conclusion you can change the crystal but you need to send it to futaba to have them check it in order to be compliant with the FCC regulations.

Well, I can certainly say that I've learned a lot from this and appreciate the discussion guys. We all have to remember that safety really is top priority!!

Tony

redfox435cat

Yes it is illegal to change your Tx crystal without a tech retuning it and yes the FCC is the governing body that enforces it. Problem is they are spread to thin to do anything about it. DO NOT CHANGE YOUR TX CRYSTAL. A the rule shows it is OK to change a modual. A crystal is not a modual. This is a modual [link=http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXH258**&P=0]modual[/link] . Course the 7c does not use moduals. If your stuck on changeing the channal on the Tx send it in to have it retuned. Not a bad idea to have it cheacked out anyway. I send my stuff in every other year to have it checked on

change your Rx crystals to match the Tx. The Tx crystal is easily changeable because other countries don't care or watch it and this is the same unit sold worldwide.

MerlinL14

The evidence is there in black and white, stop saying it is illegal, when in fact it is NOT. Is is NOT APPROVED, the FCC label on your Tx even say's FCC type APPROVAL. No one is disputing that you should not change your Tx crystal without having it re-approved by a licenced engineer. Even the qualification of the type approver is a grey area, reading the specific chapters leads you to believe that even a licenced radio ham has the authority under these rules to carry out this operation.

Bottom line is it is your call, change it and suffer the consequences when something goes pear shaped! Or send it in and get it re-approved knowing that you are no not responsible if it goes pear shaped!

Also I think your club officers would have a say in whether you would be allowed to fly knowing that you just swapped out your Tx crystal, and understanding the liability issues raised by un-approving a Tx.

still burnin

To clear things up for me, is it OK to change the RX crystal?

redfox435cat

yes the rx crystal is not a problem to change. most can be changed to any were in the spectrum. Futaba has a Hi low band which is cut some were around channel 30. just make sure you don't cross brands. if you get a futaba rx use a futaba crystal. hi-tec to hi-tec jr-jr and so on.

Also make sure you use a dual conversion crystal on a duel conversion rx and single conversion on a single conversion

BarracudaHockey

My Feedback: (11)

If you don't think the FCC has regulatory powers (and I find this odd that someone that doesn't live in this country is adamant what is legal here) just ask Clear Channel Communicatons.

Deadeye

Weren't they the ones that got a 'Stern' fine?

BarracudaHockey

My Feedback: (11)

Yep, him and Bubba the Love Sponge.

It was well into 6 figures, maybe 7, I cant remember exactly.

BarracudaHockey

My Feedback: (11)

Yep, him and Bubba the Love Sponge.

One fine was 495,000 and the other 1.7 mil

MerlinL14

Why should the fact I live in the UK make any difference to what I read in the FCC document?? It was in clear English, which is my first languge!!!
The case with Clear Channel was filed through the Federal courts the FCC has NO DIRECT judicial powers to fine or penalise anyone. I have never said they don't have "regulatory powers" they do and are the administors of those regulations.
I'm not being funny here, but have you or the other posters who are so adament about this acually sat down and read the regulations!! I thought maybe as you lived in the country that is regulating the Freq you are using it would be of benefit.

redfox435cat

Then quit blatantly and grossly misinterpreting the rules. I'll say it again.

A crystal is not a module.

Also let say it was.[:-] The rule states. Modules which were certified as part of your r/c tx.
meaning you can replace the crystal with an identical crystal. any other crystal would not be certified for that unit. now before you came back with well a module would come under that criteria as well here is the difference

With an American radio that if FCC certified. you'll see a couple things

an FCC id number.

the crystal with the frequency
a little round sticker with a frequency that matches the crystal.
this is a compliant devise. if the crystal and the sticker doesn't match it's not a compliant devise

On a module all this info in on the modual box. When pulled off all the transmitting cuircitry is on the module

You can try to skew it all you want to. Also to even come up with the idea thee FCC doesn't have the authority to regulate it is ludicrous. Whether or not they do anything about it another matter

MerlinL14

Read the document, then tell me I am misinterpreting the rules, I take yot have sat down and read them, or are you just another "someones brothers, mate told me" brigade??
Show me where I said it was??
Again read the FCC document, it clearly states that they have to apply through the federal judicial system to bring about a prosicution!!
AGAIN, show me where I said the FCC dont have regulatory powers??

I'm done here. If you can't be bothered to read the documents or my replies without misquoting then I am beating a dead horse.
I didn't reply to the Thread starter to piss off the "know it all's" I set out to post the FACTS.

redfox435cat

yes I've read it and several times since we've had to kick a guy out of our club for it after a 1/3 scale plane nearly hit the pit area cuased by a newbie on an ajacent channel and didn't see anything wrong with changing his crystals around

I keep forgetting. Your not from this country. So any argument is irrelevant. As usually your using a technicality to prove nonsense. The fcc has full authority to tell you stop doing what your doing. they have the right to physically take your equipment if found to be the source of interference. You are required to surender your equipment for inspection. If gone far enough they take you to court just like any other agency. A state trooper doesn't phically fine your or have you put in jail. the court does. a fish and game warden doesn't phsically fine your the court does. What your failing to realize is they are all the the same team and is part of due prosses. see this isn't a police state which boils down to yes the feild officer doesn't have the authority to punish you direcly but send you in the right direction. any have fun and keep em flying

MerlinL14

What the hell does me being from the UK have to do with the answers I have given to the thread starter?? Or are you using this as a cop out on your replies to me!!!!
You still haven't quantified why you misquoted my replies, but continue to use my country of birth as a reason to why "you are right and I am wrong"

What technicality??