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Illegal radios?

Old 01-02-2004, 03:22 AM
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whstlngdeath
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Default Illegal radios?

A while back I was checking out some transmitters for sale at a local swap meet, and noticed some Futabas that apparently had their crystals changed to another frequency. The original factory stickers that show the freq. were still on the backs, and the plastic crystal housings up front matched, but when I pulled one out to check, it was a different freq. Three of the four xmtrs for sale had wrong crystals in them. I asked the seller and he said that he had used them all in their current configurations with no problems. My question is, besides the FCC making it illegal for us to change xmtr frequencies, does it present a real danger that these renegade transmitters are out there and could possibly cause problems at a busy field? I wonder how many at my local field are using these transmitters either knowingly or unwittingly?
I've also read that this "problem" is really just a U.S. thing and others in other countries are free to change frequencies in their transmitters at will. In fact, that is the reason that the crystals are accessible on the outside of the xmtr case. Manufacturing costs keep the radio makers from making radios with "non-accessible" crystals for the U.S. market and "accessible"
crystal radios for the rest of the world. We all get the same radio case, but here we are supposed to know that replacing the crystal for the sake of a freq. change is a no-no. What are everyone's thoughts on this?

Jesse
Old 01-02-2004, 05:37 AM
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chines
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Default RE: Illegal radios?

I dont really know a about this but cant you buy them for say tower hobbies if someone is on your freq, so you can change them out and fly? someone let me know???

Chris
Old 01-02-2004, 11:54 AM
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LesUyeda
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Default RE: Illegal radios?

We may be all getting the same radio case, but we do not all have the same transmission requirements. In the US, we have commercial equipment sandwiched in between our channels (rather we are sandwiched in between commercial equipment) and if the transmitter has it's frequency changed, and is not retuned to the new frequency, there is the very real possibility that it will interfere with that 250' radio controlled crane that is right next to you. There are real reasons for the rules. One should learn to follow them.

Les
Old 01-02-2004, 02:20 PM
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DBCherry
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Default RE: Illegal radios?

Yes it is illegal in the US to cahnge transmitter frequencies (crystals). And it is possible that you will depreciate the transmitter's performance.

While I doubt that the FCC is going to track you down and throw you in jail, the fact that it's illegal should prevent you from doing it. Besides, there are commercial and industrial entities constantly trying to pursuade the FCC to give them some of our "channels". Why give the FCC a reason to do it, and if we start abusing the regulations it just might be reason enough.
Dennis-
Old 01-02-2004, 02:35 PM
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DeepSpace
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Default RE: Illegal radios?

Was it frequency or channel? Lets say 35MHz to 40MHz or channel 75 to 86?
Old 01-02-2004, 04:34 PM
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whstlngdeath
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Default RE: Illegal radios?

Frequency is the channel. The band is the Mhz.

Jesse
Old 01-02-2004, 05:39 PM
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Default RE: Illegal radios?

ORIGINAL: whstlngdeath

Frequency is the channel. The band is the Mhz.

Jesse

Aha, so you aren't allowed to change the channels? Here you can buy a radio and then then you can take any channel you want (within the Band) and change it any time you want.
Old 01-02-2004, 06:00 PM
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whstlngdeath
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Default RE: Illegal radios?

That's right. Here in the U.S. our governmental department that regulates the airwaves has deemed it illegal to swap frequencies in the transmitter. We can swap them in the receivers. We share the same bandwith that other consumer devices are on as well as some commercial frequencies. The channels we use are seperated by 20khz, I believe, so there isn't much room for error. If someone swaps out a transmitter crystal and doesn't have the xmtr retuned, it could interfere with other transmitters at the field or some of the other nearby users of the same band.

Jesse
Old 01-02-2004, 06:42 PM
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Scott McCrory
 
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Default RE: Illegal radios?

What about the Hitec and Futaba frequency modules that can be set to any channel?

Scott
Old 01-02-2004, 07:04 PM
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whstlngdeath
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Default RE: Illegal radios?

Those are synthesized systems that allow you to change the frequency without changing the crystal. It's the equivalent of tuning the radio to the new frequency.

Jesse
Old 01-02-2004, 07:30 PM
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rwh
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Default RE: Illegal radios?

What do you mean that the plastic case had the correct channel, but the crystals were marked wrong?

I don't think our channel frequency is the same as the actual crystal frequency.
Old 01-02-2004, 07:35 PM
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Flypaper 2
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Default RE: Illegal radios?

I believe the whole RF circuit is in the module.
Old 01-02-2004, 07:59 PM
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whstlngdeath
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Default RE: Illegal radios?

rwh,
The channel number such as 30 and the frequency such as 72.390 are one and the same. Futaba puts a sticker on the outside of the back of the case that will list both of those numbers to show what channel, (frequency), the radio had when it left the factory. The actual crystal itself, if it is a genuine Futaba one, also has the frequency numbers on a stick-on tab on the body of the crystal. What was on the body of the crystals did not match the stickers on the cases.

Jesse
Old 01-03-2004, 01:51 PM
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c/f
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Default RE: Illegal radios?

This thread is the most bogus piece of information I've ever read @ RCU.

Changing a xmtr to another channel allowed for RC use is allowed and practiced at National level competitions, yes even at the AMA site, onsite. Certain venues such as pylon racing and combat it is routine to have crystals on hand to swap out to solve conflicts.

Some other facts you may find interesting is that JR and others have a complete xmtr module that you can change out (not synthesized as reported) and yes even change to different Bands, ie, I fly my JR 10X in combat using a normal 72mhz range channel #53 module, then I swap out the module to a HAM band 53hz range module for flying jet turbines.

I also have spare crystals for combat on adjacent numbers ie. 51,52, to swap out within the 72mh module when conflicts arise. How far you can go from the original number does have a tuning issue, older sytems for sure.


Proper marking and knowledge of what a xmtr is in fact transmitting on, is a pilots responseability. This is the thing I find scary with this post, as most newbies could fall prey to this when purchasing from swap shops and auctions. Proper changing out of transmitting freq on toadays modern radios could never be traced to the originally shipped freq so I doubt how this could even be legislated to be illegal.


Some thing the FCC does not allow is using crystals from differing brands in differing xmtrs. ie, many are using Hitec xmtr crystals in Futaba radios since they are cheaper and are reported to work better than OEM. but this is not allowed according to the FCC and AMA.

And here is another bit of FYI you might find interesting, IF and WHEN the FCC allows a transmitter to be legally manufactered and sold in commerce, it can NEVER be deemed illegal for use in it's intended original manner.

What this means is that the old non GOLD AMA stickered transmitters are in fact totally legal to use, The only thing "illegal" is the AMA has outlawed their use for insureability. They do not have the power to make them illegal.............
Old 01-03-2004, 07:44 PM
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whstlngdeath
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Default RE: Illegal radios?

Sorry c/f, but you are confused.
Look at the AMA membership manual on page 17, it states:
"any user modification of a transmitter that might affect the transmitted signal is prohibited by law and safety concerns. This includes user replacement of frequency determining plug-in crystals and use of plug-in frequency modules from another manufacturer. Transmitter crystal replacement, with or without a change in frequency, requires transmitter emission realignment by the manufacturer. Use of a frequency determining module manufactured for use in another brand transmitter, can result in off frequency and spurious emissions that cause interference to other flyers."
The changing out of crystals and the changing out of "other brand" modules are two separate things. NO crystal can be changed on a transmitter to a different frequency regardless of brand. Only the modules are addressed as brand-related changes, not the crystals. This is a FCC requirement, not the AMA. We are to conform to FCC regs in complying with the AMA. I seriously doubt that a contest director will allow the changing of crystals like you state you do.
No doubt, you and your cohorts are doing this illegally, behind the CD's back. I suggest a more thorough read of the rules before you get into some hot water at a contest, or worse, cause the crash of yours or someone else's plane.

Jesse
Old 01-03-2004, 08:12 PM
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feihu-RCU
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Default RE: Illegal radios?

c/f:

I have and old radio on 72.400 mh. If I understand you correctly, I can still use this radio legally by the FCC; however, it is illegal for use in an AMA environment.

Also, I have an Ace radio on ch 52 that I have modified by installing Ace Dual Rate modules. As I understand it, this is OK so long as the RF module and associated circuitry is not modified. Is this correct?

feihu
Old 01-03-2004, 10:41 PM
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The_Matrix
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Default RE: Illegal radios?

ORIGINAL: whstlngdeath

A while back I was checking out some transmitters for sale at a local swap meet, and noticed some Futabas that apparently had their crystals changed to another frequency. The original factory stickers that show the freq. were still on the backs, and the plastic crystal housings up front matched, but when I pulled one out to check, it was a different freq. Three of the four xmtrs for sale had wrong crystals in them. I asked the seller and he said that he had used them all in their current configurations with no problems. My question is, besides the FCC making it illegal for us to change xmtr frequencies, does it present a real danger that these renegade transmitters are out there and could possibly cause problems at a busy field? I wonder how many at my local field are using these transmitters either knowingly or unwittingly?
I've also read that this "problem" is really just a U.S. thing and others in other countries are free to change frequencies in their transmitters at will. In fact, that is the reason that the crystals are accessible on the outside of the xmtr case. Manufacturing costs keep the radio makers from making radios with "non-accessible" crystals for the U.S. market and "accessible"
crystal radios for the rest of the world. We all get the same radio case, but here we are supposed to know that replacing the crystal for the sake of a freq. change is a no-no. What are everyone's thoughts on this?

Jesse

This may have been older radios that were updated a fews back due to FCC changes. For those that remember you went from a Silver Label to a Gold Label on the TX.
Old 01-03-2004, 11:29 PM
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Tall Paul
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Default RE: Illegal radios?

There's a big gap between the "law" and the practice.
And these frequency swaps are NOT done surreptiously when frequency conflicts come up at contests...
read this part again...
"Changing a xmtr to another channel allowed for RC use is allowed and practiced at National level competitions, yes even at the AMA site, onsite. Certain venues such as pylon racing and combat it is routine to have crystals on hand to swap out to solve conflicts."
Experienced fliers will have a complete set of crystals to cover contingencies..
Other places on the planet DO permit swapping crystals at will....
Old 01-04-2004, 12:01 AM
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RCKen
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Default RE: Illegal radios?

Guess that I'm going to throw some fuel on the fire here. Hitec Eclipse 7 transmitter has the ability to select any of 50 available channels to fly on. Polk's Modelcraft makes the Tracker II transmitter that automatically searchs for channels that are being used when you turn the transmitter on. Gives you a read out of the available channels to choose from.

As far as the AMA outlawing the practice of changing channels?? well I don't know for sure if this is true or not. But I will say this much. The information about the two listed transmitters above was found on page 53 of February 2004 of Model Aviation. that is the OFFICIAL PUBLICATION of the Academy of Model Aeronautics. If this article was printed with information that goes against the AMA By-law, then I think that the AMA needs to find new editors for their magazine.

Before I wrapped up this response I looked at the AMA membership guide. I couldn't find anything on page 17 that says we can't do this. but I did find this section under transmitters.

5.3.5.Transmitters that are configured for user frequency selection via
RF module changing, switching, or synthesized techniques are permitted.
However, transmitter output must be within the guidelines listed in
paragraph 5.3.3, irrespective of the operating frequency selected.


Just my 2 cents worth. I'll get down from my soapbox now.
Old 01-04-2004, 12:08 AM
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whstlngdeath
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Default RE: Illegal radios?

RCKen,
Very true. The radios you list are a different breed from the older style which has the RF section of the radio built-in the case and cannot be accessed. The RF section of the radio is the part that determines what frequency the radio transmits at. On the older radios, this RF section is built into the radio internally, and can't, (shouldn't), be accessed by the end user. On the newer radios, changing out the module is the equivalent of changing out the entire transmitter.
The RF section is entirely in the module, and you are really swapping out one transmitter for another when you use those. Changing out just a crystal on the older radios, but not retuning the RF section to the new crystal's frequency is what the FCC frowns upon.

Jesse
Old 01-04-2004, 12:32 AM
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john 8750
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Default RE: Illegal radios?

I didnt know that the newer RF output circuits were tuneable. Thought they are a single chip and a crystal.
If it is illegal to change transmitter crystals then why are the crystals sticking out of the back and easy to get at?
Just wondering.
Old 01-04-2004, 12:40 AM
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whstlngdeath
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Default RE: Illegal radios?

John,
Check out the first post in this thread. The manufacturers want to keep the costs down. Only in the US are we not allowed to change the crystal in our transmitters. Anywhere else, there is no regulation on it. The manufacturers design only one type of transmitter case for everyone. Instead of making a case for the users in the U.S. with a hard to get at crystal, and then one for the rest of the world, they just make one and hope nobody swaps out the crystal.
Guys, the whole purpose of this thread was to see just how much people are aware of the FCC regulations and how we as modelers fall within them. Another thing I wanted to know is, just how critical is it that we not swap out our crystals? If others around the world are allowed, then is it just politics here or is there something more to it? You'd think that if swapping out the transmitter crystal for the sake of changing the frequency, you'd hear of all kinds of interference-related crashes going on. I just think that there are a lot more radios with "wrong" crystals in them than we realize. Whether this is a real problem or not was the end I was seeking through this thread.

Jesse
Old 01-04-2004, 12:03 PM
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Default RE: Illegal radios?

I can not determine whether c/f is intentionally trolling for comments by using bad or uneducated statements or if he is really as uniformed as his statements appear. Regardless, in the USA we (the hobbiest) is a secondary user of these frequencies and there are many commercial paying users of the frequencies sandwiched in between each of our assigned frequencies. Any time you change out a crystal in a unit not designed for it you can cause interferance to these users even though you can still get your job done. This could cause serious damage or even loss of life to these other users if your transmitter platters into their assigned frequencies. Since you do not know if you need an X cut or Y cut crystal in your transmitter and may use the wrong one, this alone can cause problems. Also, all crystals have a tolerance, they are mechanically ground quartz and usually need padding with inductance or capacitance to be exactly on frequency. That is why you must have the proper tools and training to adjust them when you change crystals. Neither is inexpensive, may exceed 4 figure values. All we need is a few accidents to happen to the paying users of these frequencies sandwiched in between ours for us to loose all our privledges so please obey the law, our very future depends on it.
Old 01-04-2004, 03:30 PM
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c/f
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Default RE: Illegal radios?

OK,

I'm confused it does'nt happen, I guess in 28 years on the contest curcuit and 75+ trophies latter this issues has as much relevance to real world application as does the posted speed limit.
Old 01-04-2004, 06:13 PM
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Default RE: Illegal radios?

It happens everywhere, and at almost every club. The FCC is the one responsible for that LAW, yes LAW. According to the FCC it is illegal for a Transmitter crystal to b e changed or installed by anyone other than a certified tech on the equipment the crystal is being changed in. You can legally change the RX crystal, but not TX crystal. How many people out there actually send their Radios back to the manufactorer thought just to unplug a crsytal and swap it for another?

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