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All Forums >> Radios, Batteries, Clubhouse and more >> RC Radios, Transmitters, Receivers, Servos, gyros >> changing tx crystals
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changing tx crystals - 4/9/2003 6:49:59 AM   
MO_Radio_Tech


 

Posts: 337
Joined: 6/29/2002
From: MO
Status: offline 		I don't care if you break the LAW, just don't crash your trainer into my car.

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changing tx crystals - 4/9/2003 6:52:24 AM   
strato911



Posts: 1479
Joined: 9/17/2002
From: Winnipeg, MB, CANADA
Status: offline 		Also, in some states and some provinces (I'm from Canada), radar detectors are legal to sell, legal to buy, but they are not legal to use...


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changing tx crystals - 4/9/2003 6:54:32 AM   
Pete the Geek


 

Posts: 21
Joined: 3/3/2003
From: Russellville, AR
Status: offline 		Look, I'm not trying to be a jerk here or anything...it makes no sense though that the crystal would be plugged into the back of the radio, in plain sight, no glue or anything to hold it into place and be able to pull it out easily and replace it with another when by stratos own post about FCC regulations clearly states that the crystal "must not be easily accessible by the user" Common sense tells me that in no way would Hitec be able to pass this through FCC regs unless it were legal...catch my logic on this?

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       Post #: 28

changing tx crystals - 4/9/2003 7:07:48 AM   
strato911



Posts: 1479
Joined: 9/17/2002
From: Winnipeg, MB, CANADA
Status: offline 		Pete - I have to agree with you that they are to easily swapped to meet the FCC regulations. When they send a sample in for certification, they surely glue the crystal in well. The design for the case is the same regardless which country, and since it is legal to swap crystals outside North America, they design the case to suit that need as well. For North America they are supposed to glue the crystal cover on to prevent us from accessing the crystal, but they try to save every penny, and scrimp on the glue. End result is the glue lets go at a slight tug, and you're in.

< Message edited by strato911 -- Apr 9 2003 2:15AM >


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I try to learn from other people's mistakes...
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       Post #: 29

changing tx crystals - 4/9/2003 7:10:57 AM   
MO_Radio_Tech


 

Posts: 337
Joined: 6/29/2002
From: MO
Status: offline 		The FCC does not choose to enforce all of its regulations all the time. In particular, they don't care much about crystal accessabilty. However, if a crystal swapper causes a problem, guess who will be prosecuted. not Hitec, but the crystal swapper. The AMA and homeowner's insurance will also refuse to cover you. You will be sued for the shirt on your back by some crook lawyer and pay a huge fine to the FCC.

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They never built a plane I could not crash!!! Can I fly yours?

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changing tx crystals - 4/9/2003 7:22:54 AM   
strato911



Posts: 1479
Joined: 9/17/2002
From: Winnipeg, MB, CANADA
Status: offline 		Since the 27Mhz band is not shared with industrial users (that I know of), there is less danger involved with an out of tune transmitter due to crystal swapping.

Also, I read that the higher the frequency, the more "touchy" the tuning of the RF circuit is. The 27Mhz band has far fewer channels (6) in it than the 72Mhz band (50), spanning a much smaller chunk of the airwaves, so even if you go from one extreme end to the other on 27Mhz, it will be less likely to be out of tune than if you change a 72Mhz transmitter by 3-4 channels.


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I try to learn from other people's mistakes...
I won't live long enough to make them all myself.

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       Post #: 31

changing tx crystals - 4/9/2003 8:09:54 AM   
Pete the Geek


 

Posts: 21
Joined: 3/3/2003
From: Russellville, AR
Status: offline 		Well, as far as the insurance part of it is concerned, I would be lucky if a hospital would let me in the door, so no biggie there

I am not arguing the legality of this, as you would know more about this then I would obviously....but it seems ridiculous to me that the penalties for this would go to the consumer alone, especially if the party had no knowledge of what crystal was actually in the radio in the first place....the average joe (like me apparently) is going to assume that 1=1, 27.045=27.045. Let's say I sold my radio to average joe with the TX at 26.995 and a crystal at 27.045. Joe loses control and hits a car. Joe will be responsible for paying for the damage certainly, but unless the victim involved is aware of all FCC regulations regarding R/C flight, how would this really even become an issue?? Also, who would be the responsible party..Joe who had no knowledge of said radio with crystal swap, or the guy who moved to Cleveland who sold Joe the radio? Certainly the company would be to blame in this scenario I would imagine...anyway, eventually I will invest in a better radio/setup, and all of this will be a non-issue..plus, I fly in the middle of nowhere..hopefully the cows don't know FCC regs verbatim

From Hitec's Focus FAQ page

Q. How can I change the frequency on my transmitter?
A. Hitec offers both 72MHz AM receiver and transmitter crystals through our extensive hobby dealer network. With AM radios you can simply swap out the crystals, do a range check, and go fly.

** Notice there is no disclaimer here about North American frquency, FCC regulations...basically Hitec is saying this is perfectly acceptable....I think if it came to a lawsuit, someone could easily win this case (or at least get their fine money back and then some from Hitec) Surely Hitec is not that gullible..I dunno. Ok, my crusade has ended...at least I have a heads up now on some of the FCC regulations, so I've learned some useful info already!!

< Message edited by Pete the Geek -- Apr 9 2003 4:08AM >

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       Post #: 32

changing tx crystals - 4/9/2003 9:59:17 AM   
strato911



Posts: 1479
Joined: 9/17/2002
From: Winnipeg, MB, CANADA
Status: offline 		[QUOTE]Originally posted by Pete the Geek
Also, who would be the responsible party..Joe who had no knowledge of said radio with crystal swap, or the guy who moved to Cleveland who sold Joe the radio? Certainly the company would be to blame in this scenario I would imagine.[/QUOTE]Please notice in my previous post that the FCC has to prove you WILLFULLY violated their regulations. Therefore, "Joe", who bought the radio after it was changed is not liable unless they can prove he knew it had been altered. The person who made the channel change without re-tuning would be liable.

As for Hitec selling crystals, I assume they either are unaware of the FCC violation caused by swapping the crystals, or they have applied for a caveat allowing their systems to have the crystals swapped (but I doubt it).

Remember, Hitec is not breaking the law by selling the crystals - the RC enthusiast who swaps the crystals is the lawbreaker. Any low priced lawyer (and I'm sure thiers are high priced) should be able to protect Hitec in this scenario.

Pete - if you're in the middle of nowhere, what does it matter which channel you're on?

As MO_Radio_Tech pointed out, the FCC doesn't go running around enforcing these regulations, but it is a good idea to know when you are breaking the law so that you can make an informed decision. I know I'm breaking the law when I exceed the speed limit, but I still do it once in a while. I swapped a crystal once, many years ago before I knew better. It too was in a 72Mhz AM radio (Futaba Attack 4 from ch24 to ch26). I won't do it again though - I can afford the occasional speeding ticket, but I don't have $10,000 to spare, so I just bought a Tracker_II from [URL=http://www.polkshobby.com/index.html]Polk's Hobby[/URL]. It is a synthesized radio and receiver, which allows me to use any channel without any legal problems, and no modules to swap.


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I try to learn from other people's mistakes...
I won't live long enough to make them all myself.

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       Post #: 33

changing tx crystals - 4/9/2003 3:45:46 PM   
Pete the Geek


 

Posts: 21
Joined: 3/3/2003
From: Russellville, AR
Status: offline 		If the FCC comes knocking at my door, just call me "Joe" This thread will self combust in 5-4-3-2-1.......but in all seriousness, I think even if the FCC caught on to the whole swapping crystals thing, it would be too easy to plead ignorance. How can someone prove that the violator had previous knowledge that this in fact was against FCC policy...as far as your arguments that speeding is against the law, yet people do this...well, there are plenty of speed limit signs dotting the highways and interstates, so there are no excuses there...not everyone actually researches FCC code violations that is into R/C, so I would imagine this happens quite often. All I'm saying is that if these penalties can be as stiff as you are claiming (and I don't doubt this one bit), this knowledge should be spread by the companies who will sell you the illegal crystal. If they are not the violators in this scenario, I don't know who is.

Thanks again for a very interesting thread....as I said before, now I have a heads up on some of the laws governing this hobby.

< Message edited by Pete the Geek -- Apr 9 2003 11:06AM >

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       Post #: 34

changing tx crystals - 4/9/2003 4:36:53 PM   
Steve Lewin


 

Posts: 904
Joined: 3/18/2002
From: Reading, UNITED KINGDOM
Status: offline 		Just to add a little spice, AFAIK Multiplex are only ones who have an FCC exemption allowing their users to change Tx crystals. Even if they are now owned by Hitec I'm pretty sure this exemption doesn't extend to the whole Hitec range .

Pete there's nothing illegal about a crystal. It's only you using it without getting the Tx chekced/retuned that's against the regs. I think the companies would argue that their gluing the crystal holder in is enough of a hint for you to realise that you're not supposed to mess with it. In fact I'm pretty sure that they all have exemptions which say that the blob of glue meets the requirements of 95.645.

BTW just for my interest, we keep talking about this being "illegal". Is it the case in your country that FCC regulations automatically have the force of law ? Anyone know if breaking the regs is a criminal offence or just a civil matter ?

Steve

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       Post #: 35

changing tx crystals - 4/9/2003 10:20:39 PM   
strato911



Posts: 1479
Joined: 9/17/2002
From: Winnipeg, MB, CANADA
Status: offline 		Pete - there's a rather famous (or infamous) saying - Ignorance of the law is no excuse.

Steve - The FCC regulations are co-related with the Communications Act. AFAIK, that means that breaking these regulations would be against the law as stated in the Communications Act.

I'm no lawyer, but I do respect the law - Civil Law or Criminal Law.


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I try to learn from other people's mistakes...
I won't live long enough to make them all myself.

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       Post #: 36

Xtal swapping - 4/9/2003 11:53:32 PM   
FlyinBrian


 

Posts: 54
Joined: 4/8/2003
From: NorthamptonNorthants, UNITED KINGDOM
Status: offline 		I'm no RF boffin but I am sure I have read somewhere that the willy nilly swapping of frequencies can lead to problems as the circuits that use the xtal can only operate reliably within a few tens of Khz of the original frequency. So you may get away with moving a few channels either side of the original freq but can cause yourself (and possibly others?) problems by swapping from one end of the band to another. Possibly this is what the FCC try to guard against?

What I can not understand is why its ok (in the USA) to move a switch or knob on a synthersised Tx but not ok to swap a xtal, without retuning and certification.

Personally I tend to stick to the same freq the Tx came with but I am a bit of a Ludite.

Re 27Meg - there is much larger spacings between channels (20 / 30 Khz I think) so I guess changing xtals should be less risky in that band.

If you really need frequency flexibilty - buy a few sets with different frequencies, lets face it non computer and low end computer sets are not expensive and you only need to avoid the mistake of flying a model with the wrong tx memory selected once to recoup the cost of the extra tx.

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       Post #: 37

changing tx crystals - 4/10/2003 5:14:06 AM   
Ladyflyer



Posts: 1035
Joined: 1/13/2002
From: North Am, PA, USA
Status: offline 		Hello Brian ,
This has been discussed here OFTEN. A search will bring up the reasons AND the people who defy reason.
Here in the US there are MANY industrial LICENSED users . They are in between our frequencies, 10 kHZ away from us. The unreasonable ,un knowing can and will put the WRONG crystal INSIDE the transmitter (and they are ALL INSIDE the transmitters). The possibility of interfering with a crane or other industrial equipment is the reason we are not allowed to pull the crystal OUT of our transmitters and replace them willy nilly. We have about 100 channels BECAUSE the people who bargained the spectrum FOR us made this agreement. We could easily lose them if a few inconsiderate fail to honor that agreement.

You are right it is NOT a matter of TUNING it never was. The synth modules are the same module with a PLL osc instead of a crystal osc.

Actually a synth module costs less than most swappers have tied up in crystals. The cheapskates out smart themselves don't they ?
Smart times one half at best !

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LF
When they have to say "NO FEAR" it really means NO SENSE.

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       Post #: 38

changing tx crystals - 4/10/2003 5:22:18 AM   
Prboz-RCU-delete



Posts: 50
Joined: 10/3/2002
From:
Status: offline 		Ok so What is the Law in Australia 36Mhz ?

Any body know this one?

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Prboz

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       Post #: 39

changing tx crystals - 4/10/2003 5:44:39 AM   
Pete the Geek