Radio without xtal

Hello group -
I bought a radio without battery or xtal to use just with computer simulation flight software. Now I'm wondering if I could use it with a
plane I'm about to buy. The plane comes with engine, servos & receiver.
The radio is a Futaba T4YF. On the back there is a sticker that says 26, 72.310 MHz - so I'm thinking it was set up for channel 26, right? So if the receiver in the plane doesn't understand this I buy a new receiver and the system works, right?
Anyone see any problems with this plan?
Tnx - LeeH
--
To reply substitute centurytel for nospam.

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Wouldn't it make more sense if you put a new or good nicad pack in the transmitter and plugged in a crystal ..in the transmitter..that matched your current receiver? Should work just fine. Buying another receiver would not be particularly cost effective...in my opinion.
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Lee Hopper wrote:

Are you in the US? If so, the first problem is it's against FCC regulations to change the transmitter crystal on your own. You need to send it to a licensed repair person to be sure the transmitter is within specs with the new crystal. Many people will tell you it's ok to do it on your own. That's complete B.S. The FCC rule is in place to protect other people who share the narrowly spaced frequencies being used by R/C fliers. Including shipping, this will probably end up costing $30-50. Note, this assumes that they don't discover a problem with the transmitter while they're trying to tune it to the new crystal.
Moving on. You didn't say what kind of receiver you got. It may or may not be compatable with your transmitter. If it is, great, all you've bought is a couple crystals. However, if it isn't, you now need a new receiver and crystal too. Receiver crystal, $14 (including shipping), new receiver, $50 (an approximation, will not be much lower).
How about the batteries for the transmitter and receiver? Are those in good shape? If not, you'll be buying those too. Receiver battery $10-20, transmitter, $15-30.
This is adding up, isn't it? We haven't even talked about the servos and whether they are in good shape. Here's another option, which in the long run may be easier. You can buy a new 4 channel system for $90-130. This system will include a new transmitter, receiver, battery packs, crystals, servos, switch harness, charger, etc. You'll start off knowing everything is in perfect working order, and you'll still have the old transmitter to use with your simulator. Here's an example: http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LWB178 **&P=1 Use ad number 011T4 in on your shopping cart box and they'll knock $20 off your order.
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C G wrote:

No, THAT is cxomplete BS. Provided you get te crystal that is matched to teh make of transmitter, it will be withing spec, especially if it matches the channel for which teh TX is set up.
In Europe we change crytsals all teh time qquite legally, and teh only problems are when a vrystal from one brand is used in another brand transmitter. These have been shown to sometimes be off frequency by half a channel or even more.
Whereas fiting the correct crystal is accuraet to a 100Hz or so,
The FCC rule is in place to protect

I suspect they don't actually tune *anything* to the new crystal. Just check that its on frequenc 0-m which it will be if te hcrystal is kosher, and the sideband emnssion is correct, which it will be if you are wihin half a dozen channels of where it was originally set up.
<snip bumptious tale of woe of all the things that could go wrong if you are as dumb as Lee>
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The Natural Philosopher wrote:

You are wrong, and it's not worth arguing with you. The US law says the user can't change the tx crystal. It's done because the tx may be out of spec with a new crystal.

That's nice. However, it appears we are just a bit more careful on this side of the pond. What you do over there really doesn't matter, the rules here are different. So, your advice is meaningless if the OP is in the US.
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C G wrote:

What the law says, and what will technically work and be with US legal specs are two different things.

Look at what your law says carefully. I would be fairly certain that what is actually prohibited is operating equipment that is out of spec. And that for this reason only 'competent people' can make crystal changes.
How you adjudge competence is propbably not defined.
Ther are two issues when changing crytsla. The fiorst is, will teh actual frequency be accurate? Test done here and elsewhere show that as long as the correct brand of crystal for the transmitter is chosen, the transmitter are indeed operating on the correct frequency. If a different brand is chosen the reults are unpredictable and may be out by up to 3khz - enough to be completely illegal in anyones book.
The second issue is what sidebands the transmitter is producing outside teh allowed spectrum. In general the power stages of transmitters are not so narrowly tuned that going a few channels one way or another will make any significanbt difference. Going from one end of teh whole band to the other however may result in slightly lower transmitted power and slightly higher out of band transmission. Its unlikely that these will be out of spec, but merely sub optimal. That's all.
Sadly, to be sure, you need a few thousand dollars of spectrum analsyer and the wit to use one.
Something very few TX repair shops have. Despite calling thesmelves competent etc.
They probably just tune it up for peak output and take it in trust tht the sidebands are withing spec.
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The Natural Philosopher wrote:

The law is designed to ensure that the equipment stays within the bounds of what is needed to properly share the very closely spaced frequencies.

It defines who can make frequency changes.

I have looked at the law. And competence is defined, it's based on obtaining the proper licenses. Obtaining such licenses is based on passing tests which show competence.
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C G wrote:

Er, no it isn't.
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| You are wrong, and it's not worth arguing with you. The US law says the | user can't change the tx crystal. It's done because the tx may be out | of spec with a new crystal.
With all this arguing about the law, I'm surprised that nobody has yet actually given a link to the actual law in question. Just lots of chest pounding ...
http://www.access.gpo.gov/nara/cfr/waisidx_00/47cfr95_00.html lets you read the actual laws (look for the R/C Rule links), and http://www.vantec.com/FCCregs1.htm is a good link for the relevant bits with a little discussion.
http://www.rcgroups.com/forums/showthread.php?t 580 covers it as well, perhaps in a smaller and easier to read format than the vantec link.
Looking at the actual regulations, it looks like you can't legally change your crystals in the US. However it also says that internal repairs or internal adjustments should (not must!) be made by or supervised by `a person certified as technically qualified to perform transmitter maintenance and repair duties ... by an organization or committee representative of users in those service'.
So it's as clear as mud. :)
http://www.rcgroups.com/forums/showthread.php?t 8828 is good too, and somebody actually asked the FCC to clarify the rules there, and the FCC said you _can't_ change crystals. This would seem to be pretty authoritative.
I saw a link somewhere where somebody had gone through the FCC regulations and determined that it *was* OK to change crystals. If I recall correctly, their argument was either based on the idea that everybody was technically qualified, or on the statement about `should be made' (and not `must be made'.) I can't seem to find this now ...
http://groups.google.ca/group/rec.models.rc.air/msg/3eca525dc24d17f4 isn't quite what I was thinking of, but it does suggest that it's OK to change crystals. Of course, the R/C regulations never said you needed a commercial radio operator license -- only that adjustments _should_ be made by a person certified as technically qualified ...
Of course, that's all about the legality of the matter. Practically, the FCC isn't going to care. They're spread very thin, and don't even usually go after the CBers using thousands of watts and operating out of band, they're certainly not going to go after somebody using 1/4 watt who changed a crystal.
The _only_ time it's likely to ever be an issue is if there's a serious accident. If somebody gets injured by an R/C plane and gets dollar signs in their eyes, their lawyer will start looking for violations of any sort to bolster their case, and they'll probably zoom right in on the transmitter's stated frequency not matching the crystal if that manufacturer mounted channel sticker is still there. Same goes for somebody getting killed and the police investigating.
--
Doug McLaren, snipped-for-privacy@frenzy.com
To envision how a 4-processor system running [SunOS] 4.1.x works, think
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Doug McLaren wrote:

Actually, there are just a few gorillas who have never bothered to read the FCC regulations, or radio manufacturer's instructions, and are trying to justify ignoring the law so they can save a few $.
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| Actually, there are just a few gorillas who have never bothered to | read the FCC regulations, or radio manufacturer's instructions, and | are trying to justify ignoring the law so they can save a few $.
Actually, I was thinking of you as one of the chest-pounders. My favorite statement of yours was `However, it appears we are just a bit more careful on this side of the pond' -- truly, comedic gold, confusing `possibly restrictive' with `careful'! (And yes, I'm on the same side of the pond.)
You've been stating that the regulations are clear, but they're not. I have read them, and recently. Like most legal documents (yes, these are legal documents, with the force of law behind them), they're not that clear.
Ultimately, the regulations _do_ say who should make adjustments --
The internal repairs or internal adjustments should be performed by or under the immediate supervision and responsibility of a person certified as technically qualified to perform transmitter maintenance and repair duties in the private land mobile services and fixed services by an organization or committee representative of users in those services.
But they use the world `should' rather than `must'. `Should' is not generally a word used in legally binding phrases.
The crystals must not be easily accessible to the user -- that part is relatively clear. But that's an issue for the manufacturer, not the end user. This may say that the FCC intends for users not to change crystals, but it doesn't prohibit it, not by itself.
Generally, if a judge finds you guilty of the word of the law, but innocent according to the spirit of the law, he can (should? must?) find you innocent of the crime in a court. But it does _not_ go the other way -- in order to be found guilty, you need to be guilty of the words of the law, not the spirit. In this case, the spirit may be that you need to be qualified to change crystals, but I'm not sure the words say that.
http://www.rcgroups.com/forums/showpost.php?p 40118&postcountf gives an interpetation of the rules from somebody in the FCC. But there's contradictions in what he says -- Specifically --
He confirmed that you do NOT have to be a certified Radio Operator class technician to perform repairs. The internal repairs or internal adjustments should {note: not MUST) be performed ...
vs.
he said that we cannot legally change R/C xtals unless they are in a certified module
Assuming that changing a crystal is an internal adjustment (and it is -- the rules say so elsewhere), these two statements do not jive.
I've read over the regulations carefully enough. But I'm not a lawyer, and not any more familiar with the FCC regulations than any other amateur radio operator would be, so I certainly wouldn't suggest that people trust my interpetation of the rules.
In my last post about this, I didn't actually say which side I believed -- because I'm not quite sure. But if I were to make a guess based on the FCC regulations that I've read on the R/C service, I'd say that
1) it's illegal for manufacturers to make the transmitter crystals accessible like they have been doing, but
2) it's legal for end-users to change transmitter crystals all they want, as long as their radios stay within the rules about bandwidth and emissions and such.
Now, it would be nice if people could use a spectrum analyzer or something similar after each crystal change, but the rules do not require that -- you don't have to verify that your signal is within the bandwith allocated, as long as it is. And it would be nice if you were technically qualified to make repairs or adjustments (including crystal changes) to your transmitter, but since the regulations say `should' and not `must', I'd say it's still legal to do it, even if you're not qualified.
Now, if there was an accident and a lawsuit, they lawyers for the plaintiff certainly would look at those words about `should' and use it to bolster their case if adjustments weren't made by somebody the FCC thought should make them, but ultimately you might be found `negligent', which is not the same as guilty of violating FCC law.
Of course, what we really need is spread spectrum to come, ready to save us from all the problems associated with crystal changes. The technology is here, and indeed you can even buy modules and receivers intended for R/C car use in the 2.4 gHz band, but that's not quite sutiable for R/C plane use ...
--
Doug McLaren, snipped-for-privacy@frenzy.com
I always use my spelling chequer, so of coarse there are no missed aches.
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Doug -
Thankyou for your considered thoughts on this subject.
Just to keep the pot boiling, are you familiar with the Futaba "synthesized transmitter module"? Looks like you can change transmit frequency to be any channel in the 72MHz band but you need a reciever to match whatever channel you choose. <http://www2.towerhobbies.com/cgi-bin/wti0001p?&I=LXHKB1 for example (and *only* $90 to go with your $340 9C radio) :)
Perhaps the FCC is just lagging behind current technology in some cases. ------------- Doug McLaren wrote: ...

--
LeeH
To reply substitute centurytel for nospam.
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Ditto the thanks Doug!
Interestingly, Kraft radio had a synthesized radio some 20 years ago. And both the TX and RX could easily change freqs with the spin of a couple of switches. As I recall though, they were somewhat cost prohibitive.
And I seem to recall in more recent years a synthesized radio where you set the TX freq and the RX picked it up and adjusted automatically. I do think there was jumper cable involved in this but don't recall the details.
Chuck

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Doug McLaren wrote:

Actually, ALL of the people I know are careful about this kind of thing, there just seem to be a few people who have little concern for others who are not so careful.

I've read them too, not long before you posted the links, but before this thread appeard. They are clear enough to make it obvious what should be done. Unfortunately, the people who want to do things their own way will always find an excuse to ignore what should be done and do whatever they damn well please. Regulations are usually meaningless to people like that since they obviously know better.

Actually, they do say must in many places, such as: "You must comply with rules (see R/C Rule 18, Sec. 95.218, for the penalties for violations) when you operate a station in the R/C service".

Not by itself, but it's obvious that the FCC's intent here is that the crystal should be an internal part and that the users can't change internal parts.

They jive just fine, if you've got a radio with a user replaceable frequency module, you can change it. If you've got a radio with just a crystal, you can't change it.

Interesting that you choose to interpret the rules opposite what the anonymous FCC person said. The cite you provided made it pretty clear that the FCC said users CANNOT change crystals. Here's another person who says the average Joe should not change the crystals: http://www.bergent.net/crystals.html

Based on your interpretation, it appears you are in the camp who wants to find a loophole to justify doing what you want.

I don't care about what happens after an accident, I care about preventing them. Anecdotal observations of people who have changed their crystals and said they have no problem is not justification for ignoring the FCC regs or what's clearly documented in the manufacturer's instructions. From your cite: '(1) The xtals are accessible. Therefore, why can't I change them? [Answer] Because the xtal is an "internal" component. Please see 95.222'. This is very clear, except to those who are going to ignore the regs anyway.
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C G wrote:

And when is a crystal not a 'user replaceeable frequency module' ?
I'd say thats exactly what it is.
The fact that futaba et al can change freqeuncies without changing te power stage tuning implies that its band, not spot, tuned anyway...
So in effect changing a crystal and moving a channel on a synth TX are identical in effect.
Apart from the possibility of plugging in a wrong Crystal, which can be checked in a moment with a freq counter...
..no. Its just another exaomple of a litigious culture protecting itself against the CO Jones of this world.
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The Natural Philosopher wrote:

That's nice, but since you don't know WTF you are talking about, what you say is worth nothing.

Sure, whatever you say.
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| The Natural Philosopher wrote: | > C G wrote:
| >> They jive just fine, if you've got a radio with a user replaceable | >> frequency module, you can change it. If you've got a radio with just | >> a crystal, you can't change it. | >> | > And when is a crystal not a 'user replaceeable frequency module' ? | > | > I'd say thats exactly what it is.
Common sense would certainly tell you that, right?
Well, the FCC seems to think otherwise --
(b) An R/C transmitter which incorporates plug-in frequency determining modules which are changed by the used 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.
I agree, it seems a strange distinction, but there it is ...
| That's nice, but since you don't know WTF you are talking about, what | you say is worth nothing.
Of course, C G loves to pound his chest, but won't go to the trouble of backing up his assertion, as if you weren't even worth the trouble. So it seems I've done it for him.
| > The fact that futaba et al can change freqeuncies without changing te | > power stage tuning implies that its band, not spot, tuned anyway...
I believe it's been pretty well established that this is true. But hopefully when Futaba changes a transmitter crystal, they at least measure the output on a spectrum analyzer and makes sure it's within the limits specified by the law. If that checks out OK, I doubt they do much else.
| > So in effect changing a crystal and moving a channel on a synth TX are | > identical in effect. | > | > Apart from the possibility of plugging in a wrong Crystal, which can be | > checked in a moment with a freq counter...
In a moment? That's all it takes for somebody putting in the wrong crystal to crash a plane. If you're flying with somebody else, you owe it to them to be more careful than that.
And a few of the current batch of synthesizers don't help. The Hitec Spectra has tiny little knobs to adjust, but they're so small that you could easily confuse a 3 with a 4. And to make matters worse, they're hidden from view when the module is installed. The Futaba 9C synthesized module is a little better -- the knobs are visible when installed, but they're still itty bitty.
(But there should be no doubt that synthesized modules are legal according to the FCC regulations. Really, at this point in the game, if you plan on changing transmitter crystals on a regular basis, you should just get a synthesized module and be done with it.)
| > ..no. Its just another exaomple of a litigious culture protecting itself | > against the CO Jones of this world. | | Sure, whatever you say.
The FCC regulations are not `another example of a litigious culture protecting itself'. Why would the FCC need to protect itself from litigation? The R/C section of them were written 20 or so years ago. Things have changed since then, but the regulations have not, not yet.
C G seems to think I'm looking for loopholes. Not explicitly, but if the question is `is it legal?', loopholes certainly count. The question is `is it legal for the end user to change their transmitter crystals in the US?' And I think the answer is yes, based on my reading of the FCC regulations. I'm not a lawyer, but that's my take.
I specifically did _not_ answer the question `_should_ the end user change their transmitter crystals?' or `does the FCC think that end users should change their transmitter crystals?', only if it appeared to be legal or illegal according to the current FCC regulations.
And as for the FCC person who commented on the regulations, I suspect I've actually spent more time reading that part of the regulations than he did. (Which sounds odd, but his response seemed pretty broilerplate-ish. Not that I saw his exact response, only somebody's interpetation of it.) To get a better answer, we'd probably need to get a lawyer to go over the regulations, _one familiar with FCC law_, or we'd need the FCC to make some sort of official ruling clarifying it. I imagine that a court case regarding somebody changing crystals could clarify it too, but I don't think that's likely to ever happen.
And while the FCC does specify who it thinks ought to work on transmitters, `The Natural Philosopher' would probably fit those qualifications if he were to work on a transmitter over here. So jumping on his case as being irresponsible or whatever else seems a bit silly.
--
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To err is human, but to really foul things up requires a computer.
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Doug McLaren wrote:

I'm not going to waste my time providing cites to people who don't care to read them anyway. I've had several discussions with people who assert that anyone can change the crystals. Most of them already had heard that it was something they weren't supposed to do. Even after being shown the regulations, prior discussions on the subject, and comments from experts in the industry, they still said they were going to do what they want. This discussion is just another example, as your words below show.

Yes, you ARE looking for loopholes. The FCC says the end user can't change crystals by themself. Industry experts say end users can't change crystals by themselves. Manufacturers say end users can't change the crystals by themselves. The discussion you cited ended with the same conclusion. In spite of all these sources, you still try to interpret the rules in a manner that makes it sound ok for end users to change their own crystals.

The difference is meaningless. The point to the discussion is that end users should not change the crystals. The primary reason in the US is that it's against FCC regulations. The FCC says this. The manufacturers say this. Many industry experts say this. Doing a lawyer wannabe analysis of the regulations trying to dispute these sources does little but give people an excuse to ignore the regs. I can hear Joe Sixpack now, "Dat Doug guy on dem dar usenet news thingie said it was ok, so golly, it must be ok. Hey bubba, check this out..." In the end, unless you work for the FCC, or are a judge trying a case on this subject, your interpretation of the rules is insignificant. This rule does not create a significant burden, or expense. It's pathetic that people who spend hundreds or thousands of $ on engines, radios, and models look for excuses to save the $20 to $30 it takes to properly change a crystal.
For the safety of all of us, people should follow the advice of industry experts (rather than the local bubba), the manufacturers, and FCC regulations.

When people have to answer the same question over and over, they tend to shorten it to something that's in your words, "broilerplate-ish".

Anyone who tells the average Joe that it's ok to change his own Tx crystal, if he's in the US, is ignorant, or irresponsible.
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Good! Go be a freq nazi somewhere else!

Fact is, I can change a crystal and neither you, your experts nor the FCC would be able to tell the difference. With the exception of any labels on the box.

proving there are total jerks throughout this hobby! Yet another reason I am thankful I don't have to rely on the AMA and the club system.
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Chuck Jones wrote:

I'm just telling people the rules. If you've got issues with them, it's not my problem. Take your issues elsewhere.

Yes, your lack of concern for your fellow modellers does show that you are quite a jerk.
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