Jet_A1

My Feedback: (1)

I have one futaba 6Yf skysport sport radio
72.390 Mhz ch 30 Low band.
My question is. can I change the crystal to a high band ch.
72.550 ch 38 like my other radios.
Thanks for any help
Deiv.

A10FLYR

My Feedback: (1)

I don't know about your radio but I changed a 129DP from 52 to 14 using an old Hitec/RCD crystal. Actually range checked better than the original reciever that came with the 9ZAP! Also, changed 2 148 FM recievers the same way with equal results when used with the 9ZAP!

Nathan

My Feedback: (12)

Can you change it? Yes.
Are you suppose/allowed to change it? No.

Direct from Futaba's website:

How do I change the frequency of my transmitter?
For a module unit: to change the frequency you simply remove the module and replace it with a module on the new channel. You can even change 'bands' (IE 72mHz to 75mHz). All radio frequency circuitry is in the module so there is no need to 'retune' after a module change. (However, the receiver cannot be similarly changed to change bands. If you go to a new band you MUST buy a new receiver on that band. Please see the note below regarding crystal changes, which is valid for ANY receiver where you are changing within one frequency band.) DO NOT attempt to change transmitter frequency by changing the crystal within the module. You must use a module which is properly tuned to the frequency desired.

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.

The applicable Federal Regulation is as follows:

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.


--------------------------------------------------------------------------------
What does it mean to have my TX and RX 'matched'?
When you have your transmitter and receiver 'matched' both are carefully tuned to the best possible signal input and output. This helps ensure that you receive full safe transmitting range with your equipment because the RX is receiving and the TX is broadcasting the cleanest possible signal. It is a good idea to have your TX retuned occasionally. And for safety, you should always have an RX retuned after a crystal/frequency change.

flatfour

My Feedback: (8)

Looking at Subpart E it seems that the design of the transmitter with the crystal accessible from the outside violates the rule.

SO I suppose one could argue that Futaba is manufacturing illegal radios........

Devils Advocate......

Sport_Pilot

Either that or the paragraph is refering to crystals which plug into the module itself. As long as the crystal is on the front I will change them myself. Talked to Radio South last week and they stated that most of the time changing the crystal did not require retuning of the radio. This is all crystals, a crystal just one channel up was just as likely to not require retuning as a crystal on the opposite end of the spectrum. The only thing that would require retuning is if a crystal was cut slightly off, or if the radio needed tuning before changing crystals. Also Futaba glues the crystal in and therefore does not consider them accessable. But why do they sell them?

MiL

Sounds like just legal fine print to cover their rear's to me. Like was mentioned before, why would they make the crystals so easily accessible, and sell them seperately if they needed to go back to the factory to be changed anyway?

I've swapped crystals in ground systems for r/c cars and never encountered any problems, i'm simply much more hesitant to do so with an airplane because the risk is much greater.

Here's a little info to fuel the fire. The other night i put the TX crystal from my 4 channel conquest radio into my brothers T6XA so that i could take advantage of the mixing functions. When using the 6XA (just in the confines of my garage, never tried a real range test) the servos were nervously jittering. Not enough to even actually move, but they were making noise.

My Conquest is on channel 14 (72.070) and the 6XA is on 38 (72.550). I believe 14 is on low band and 38 is on high band, and this is my guess as to whats causing the trouble.

ftomteen4cat

My guess on the accessability of the crystals? They don't just sell radios in the USA...

If they have low and high band radios, there's a good chance that their filters are tuned to the centers of those bands. Assuming they are still within those specs, they could work fine, but with reduced range. Just a thought.

Sport_Pilot

Mil,
Again most of the time crystals can be swapped from low to high without any problems. The reason the manufactures don't want you to swap crystals is because they have been in the habit of using crystals which are not as accurate as they could be. Then they retune the radio when this occurs. When you swap crystals from one of these radios then you may have problems until it is retuned.

Phil Cole

>>>>> Talked to Radio South last week and they stated that most of the time changing the crystal did not require retuning of the radio.

Most of the time isn't good enough. If it was all crystals, all the time then the FCC would probably be OK with users changing crystals. Their issue is not whether you crash your models, but whether your transmitter interferes with other licensed radio users.

>>>Also Futaba glues the crystal in and therefore does not consider them accessable.

This is a work-around with having to change the radio designs. The same designs are used in on other bands in other countries, some of which do allow users to change crystals.

>>> But why do they sell them?

Good question. They used to sell only Rx/Tx pairs, but have now made the Rx crystals available separately. I'm fairly sure this was in response to complaints about being forced to buy crystals that were illegal to use. I used to just buy Hitec Rx crystals, which also "worked OK most of the time". The only thing at risk here was the model, so I just made sure the receiver performed OK before flying it.

It isn't illegal to for them to sell them, only for non-qualified users to change them.

Sport_Pilot

Find the FCC reg that says it's against the law for the user to change external crystals. Hmmm? Only law I can find is one that says that crystal must not be accessable to the user, and that may refer to the crystal in the module. The only reason I can see for the manufactures to not allow user to change crystals is that they are using lower quality crystals.

ftomteen4cat

Sport Pilot - you'll need to read a couple sections to get it. If you read 95.222 and 95.645, that should clear it up for you.

A10FLYR

My Feedback: (1)

I must add here that I only changed the reciever crystals to match my transmitter. I do believe changing crystals in ANY transmitter by a non qualified person is illeagal. I don't think this rule applys to synthisized Xmitters as all frequencys are already put in the Xmitter by the manufacturer who has the product FCC approved with those freq's. "Ain't nutten illeagal if'n ya don't get caught"....now where did I hear that?

cubfan

It all just sounds like a bunch of legal mumbo jumbo to me. I have been changing crystals in my Futubas for years with no problems. I always range check very carefully. I have even taken a older FG Series and pulled the a.m. module and replaced it with a f.m. one, all of the signal is in the module. I have had no problems with Hitec or FMA recievers with my Futuba transmitters either.
Cubfan

Sport_Pilot

Ok. Just where does it say this. I have copied the above sections.

Subpart C--Radio Control (R/C) Radio Service

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:
(1) Repair or servicing of an R/C station transmitter (see R/C Rule
21, Sec. 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, Secs. 95.209
and 95.210.)

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

The above certainly doesn't say that I can change an external crystal. It only covers internal modifications. Changing the crystal located on the front of the transmitter is neither internal nor a modification.


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.


Ok so maybe ALL of the RC manufactures can be busted for putting the crystal on the front of the transmitter! But this doesn't say I cannot change said crystal illegally made accessable to ME!

And as for as glueing in the crystal. I didn't know that the crystal was glued in, the resistance didn't seem like it was glued but rather that the newness made it a tad stiffer. So it was accessable to me despite the glue. So maybe we should sic the FCC onto the manufactures? Naaa.

BTW I removed the crystal so it would not transmit when using a buddy cord, something I think the manufactures say is OK. So if I remove the crystal to prevent it from transmitting with a buddy cord, where does it say I have to put the same crystal back in?

wood

My Feedback: (2)

Ok guys,

I have to put my 2 cents in here.

Isn't it very important to be safe?

I would rather know I'm covered by AMA insurance if I don't change frequencies on a non module radio. Not only is it illegal, your not covered by AMA insurance if you change the crystal, like in my Futaba T6XAS. I'm on 57, want to change it to 55, but I'm not going to because it costs too much money to send it in and have the transmitter and receiver matched, AND I want to be covered by the AMA if I dice someone up with a prop or airplane. I have never had a close call, and don't fly loose. I just want everyone to be safe, and that should be your first concern, even before having fun.

Thanks,
WOOD

A10FLYR

My Feedback: (1)

Hey Wood, I think we all agree with what you say;>) We're just debating the fine points. Makes for great sh*thouse lawyering;>))

wood

My Feedback: (2)

I agree, and sorry about getting serious on everyone.

I just won't change crystals on a radio or revceiver without sending it in to be retuned.

I spoke to a Futaba tech last week and he told me I could safely change it two frequencies up or down as long as I stayed within the hi, or low bands that I was already in. So a change from 57 to 55 would work, but not legal. You would also not be covered by AMA insurance if you had an incident..........bla bla bla......

WOOD

Sport_Pilot

Hey Wood, its easy to check if you will be safe. Just do a range check on your radio, check for interferance on adjacent channels. You can do that by either checking it with friends recievers, or by changing crystals in your reciever. And the AMA cannot deny you insurance for something which is legal, read the above excerpts and tell me where it says you cannot change the crystal, hmmm?

wood

My Feedback: (2)

I guess that would be up to the AMA to interperet wouldn't it?

And I decide to not take that risk, and you do. That is my story and I'm sticking to it.

Anyone from the AMA home office want to comment on this?

WOOD

Sport_Pilot

If the AMA denied me coverage it wouldn't be for them to determine, it would be the courts to determine.

wood

My Feedback: (2)

Like I said, I choose not to take the risk and you do, that is fine.

Just to clear things up a little I called Steve Kaluf in AMA Special services to discuss this crystal changing.

This is what Steve had to say/summarize/indicate.........

1. Everyone must follow AMA safty code. Which means you must follow the FCC laws.

2. FCC declares that the radio or receiver is not a user servicable part. having a module is user feature. The radios without modules are not user serviceable. The crystal is not a user serviceable part.

3.If you changed crystals, had an accident, you would probably not be covered by AMA insurance and there is no way to determine this until the lawyers and a judge are involed.

4. If the FCC got involved and it was determined you changed crystals without retuning your radio and receiver, they could fine you $10,000.00.

I choose not to change my crystals, get sued, not be covered by AMA insurance, and be fined $10,000.00 by the FCC.

I know it is a stretch, but some day, some day everyone, someone is going to have this happen to them, and it won't be me.

You can make your own choice.
WOOD

Sport_Pilot

Asking Futaba or the AMA about FCC laws is like calling the Godfather about ATF laws! They in this together!

wood

My Feedback: (2)

Futaba told me I could get away with it, I choose not to try!

Ladyflyer

My Feedback: (2)

The crystal is NOT external it is INTERNAL . It is behind a cover inside the radio. Futaba ,the company who applied for type approval an these radios has stated they went so far as to glue the covers so they would not be so easilt removed,
As already stated the radios are sold in other countries where the rules are different ,but in the USA it is illegal to change the crystal without the proper license. Futaba was allowed to comply but in the very near future the do it yourselfers may force the manufacturers to make frequency changes far more difficult.
Of course that means the radios and freq changes will probably cost more as well.
You are right almost always getting away with it is not good enough :stupid:

MHawker

My Feedback: (16)

"Suffoco tyrannus vox vitupero ! "---- I'm sorry, could you speak into my English ear?

So, if I understand correctly, a person can't even change a crystal in an RX? Or they may face issues with insurance coverage, etc.?

My understanding up to now has always been that someone could change the RX crystal (assuming they stayed within the high or low band) and not have any problem. But, changing the TX crystal was against FCC regulation.

Mike