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-   -   tx / rx question (https://www.rcuniverse.com/forum/beginners-85/2820220-tx-rx-question.html)

Rubberduck 03-29-2005 04:31 PM

tx / rx question
 
I have a JR Quattro radio on ch #33. I want/need to switch this due to another guy at the field being on the same channel. Normally we are out there at the same time, and since he has 10+ planes on ch 33, and I have just one, it's easiest for me to switch.

The question is, can I just swap the crystals in the rx and the tx to another channel? I've read conflicting reports that say I can't change the tx crystal at all, or that I can change it if I remain in the same band. Which is it?

Thanks!

BigSkyRCFlyer 03-29-2005 04:42 PM

RE: tx / rx question
 
Send it in............

DBCherry 03-29-2005 04:44 PM

RE: tx / rx question
 
It is illegal (FCC) to change the transmitting frequency, period. I know that people do it, but you run the risk of losing range or bleeding over onto other channels.

It is fine to change receivers crystals.

Sell your Quattro and buy another one. Shouldn't cost you much to change if you buy a good used one.
Dennis-

BigSkyRCFlyer 03-29-2005 04:50 PM

RE: tx / rx question
 
.

NJAIRSTRIKE 03-29-2005 04:50 PM

RE: tx / rx question
 
with a futaba all you gotta do is change the crystal but if your receive is low band just make sure its Low band Channel 11 through 35 and not high band crystal then it would be wrong. I dont think JR has high and low band so I'm assuming that you can get whatever channel crystal you choose. I'm not 100% sure just wait a lil bit longer and you'll get better responses.

bruce88123 03-29-2005 05:27 PM

RE: tx / rx question
 
It is illegal. If you want to make sure, just call your local FCC office and tell them where to come and issue the citation and confiscate the illegal equipment at. Just because you can sometimes get away with something does not make it correct or smart. Sort of like jumping into a lake without knowing what is below the surface. They sell crystal sets so that you can take the new equipment to a proper facility and have it properly tuned and not expect the facility to stock every possible crystal. Yes, odds are in your favor but it's still not right. Synthesizer modules deal with a whole different type of freq generation and the modules have been proved and certified by the FCC to comply with all appropriate regulations. It is not illegal to jump bands in Futaba receivers but you may sacrifice range and therein lose a plane. [:'(]

-pkh- 03-29-2005 05:29 PM

RE: tx / rx question
 

ORIGINAL: BigSkyRCer
...I have never seen any type of (FCC) warning in my 20 + years of RC, maybe due to living in Montana?[8D]
Here you go.... here's Futaba's warning about swapping TX xtals, along with a quote of the FCC regulations...

http://www.futaba-rc.com/faq/service-faq.html#q2


bruce88123 03-29-2005 05:32 PM

RE: tx / rx question
 
And that does apply to Montana too.

BTW- I do have the appropriate license, FCC Commercial Radio Telephone General and I don't tune my own because I don't have the appropriate manuals to do it properly.
I tune/align aircraft radios for a major airline EVERY day but a man has to know his limitations and what he is allowed to do by law. I am NOT going to endanger my license and my job by tuning a transmitter without the proper information available. For me the would violate FCC & FAA regulations and could lead to dead people in a worst case scenario.

BigSkyRCFlyer 03-29-2005 05:32 PM

RE: tx / rx question
 
Bruce, no one said for you to endanger your license and tune an RC radio, so I don't see your point there, sorry.
Then I guess a LOT of people should be in jail.........HAHAHAHAHA Sheesh guys, chill. Mental note to self......No more Highly illegal Crystal Swaps...Everyone listen up on this. Don't do it!!! My only gripe is THERE should be more adverts on this, and warnings in view, not in the "fine" print. I am not the only one, who has done this out of "Lack of knowing" not trying to break the law. Period. I think Futaba/JR, etc, etc, should list this warning on each TX crystal they sell, most people do not know this, as we all do not work on radios and deal with the FCC. Isn't the purpose of RCU to Educate, not Flame? Dang. Now I/We know not to do this and knowing is half the battle. Good Day.

bruce88123 03-29-2005 05:49 PM

RE: tx / rx question
 
No flames were intended by me, only to be emphatic. I fully agree that it should be in large print on the front of the manual but how many of us read those either except when we have a programming question?

Sorry if anyone felt flamed, just don't want to see any lost planes for such a little thing.

Bruce :)

It would help if they didn't put the crystals in the front of the radio and make it so easy to do.

BigSkyRCFlyer 03-29-2005 05:57 PM

RE: tx / rx question
 
Bruce, I agree. I as one, did not know this. I thought you just had to send it in, for them to tune it, so you wouldn't loose range or have any issues with the electronics, I did not know it was illegal, honestly and a lot of people do not. I think the TX crystals should not be sold then, and if you want to change the channel, then you have to send it in, and they install the crystal, not buy it from Tower and then the owner sends it in, too easy to just use the radio, etc. Maybe just some better warnings about changing the TX channel with our radios and accessories.

RCKen 03-29-2005 08:30 PM

RE: tx / rx question
 
Going to repeat the same message here, but as said a few times above. DO NOT CHANGE IT YOURSELF. There are people around that will tell you to just go ahead and do it, it's easy. That's true it is easy, but think about this. You could go down to the gas station and fill your tank and drive away without paying. You would probably get away with it, but are you 100% sure you wouldn't get caught?? Legal issues aside, changing the crystals could de-tune you radio to the point that it doesn't function 100%. This is like the legal part of it, you would more than likely be fine doing it yourself, but is it worth the chance of it reducing the range of your radio? Think about this (you may not have planes this expensive, but I'm making a point.) --- Dave Patrick Ultimate Bipe-$400, YS 140 4-stroke engine-$550, misc parts-$100, high torque servos - $225, Airtronics flight pack-$115. That's almost $1,400. Cost of sending your radio in to have it retuned - $30+shipping. In my book it's cheap insurance to losing the plane.

IMHO those who tell you to do it in spite of the laws and common sense are acting irresponsibly.

Rubberduck 03-29-2005 08:54 PM

RE: tx / rx question
 
Thanks for the answers. I'll have to wait to send it in as currently it is in my only flyable plane. Once I get my 4* finished and get comfortable with that, the JR will go in to have the crystal changed. That'll give me the chance to get it fixed too (throttle trim slider doesn't "click" anymore, just slides up and down smoothly).

DBCherry 03-30-2005 06:16 AM

RE: tx / rx question
 
The reason they make the crystals so easy to change is because it's not illegal in the rest of the world, only in the US. [:o]

But our radio frequncies are so crowded that the FCC has had to regulate them closely.
Dennis-

Cyclic Hardover 03-30-2005 08:48 AM

RE: tx / rx question
 
If you had Futaba, you would not have to go through all that as long as your frequency change remained on one side of the high or low band.

I do not know how JR works on this but is a waste of money and time and its a hassle for some. As far as being illegal, you have a better chance of being hit by a 1 inch meteor than having the FCC come knocking on your door. Compare the legalities to this, its also illegal to go 31mph in a 30 mph zone.

Whatever you do, make sure you do a range check


bruce88123 03-30-2005 09:23 AM

RE: tx / rx question
 
Snoop Doggy Bag-
"If you had Futaba, you would not have to go through all that as long as your frequency change remained on one side of the high or low band."
This is true only with respect to the receivers.

"I do not know how JR works on this but is a waste of money and time and its a hassle for some."
I will have to acknowledge you may not know how JR works and that YOU consider it a waste.

There are many laws on the books that are hassles and considered wastes of time and money. They are none the less still laws. If you do not like them, campaign for a change through the AMA frequency committee. I attempt to obey the laws every day and NO I don't always manage to do it. But I don't blatantly flaunt them like you endorse.
These are my last words on this subject as the laws ARE clear
May I suggest you do not encourage others to disregard the laws
BTW- if there were to be an accident, this could also be used to show negligence and possibly give the insurance companies (including AMA) grounds to drop coverage and leave you liable for all damages.

mrbass111 03-30-2005 10:32 AM

RE: tx / rx question
 
buy the hitec optic 6 with the spectra module. you can set the tx to any channel you want. and it also can be changed to positive shift. then you can sell your jr.
http://www2.towerhobbies.com/cgi-bin...&I=LXGZS6&P=ML

2slow2matter 03-30-2005 02:38 PM

RE: tx / rx question
 


ORIGINAL: bruce88123


BTW- if there were to be an accident, this could also be used to show negligence and possibly give the insurance companies (including AMA) grounds to drop coverage and leave you liable for all damages.
That says it all right there. It's just not worth the risk to save a few bucks. For the cost of 30 bucks (2 gallons of fuel) you might save someone's life. And, you might not even realize it. You might keep your radio from bleeding into frequencies that are not RC--in other words, your plane might fly great, and you might not shoot anyone down, but are you sure you're not interfering with a construction crew down the road, or something else where someone else could potentially get hurt? You're risking everything you own, and putting your family in financial jeopardy if your insurance drops a claim.

BTW,
Ignorance is NO excuse of the law. That, by the way, is law. So it doesn't matter if you know or not. These are not wal-mart toys we're dealing with here.

Cyclic Hardover 03-30-2005 07:17 PM

RE: tx / rx question
 
oh! oh! oh! Okay! Listen Bruce, I am so sorry for being so ignorant, unsafe and thinking only of myself. I am not going to waste my time mincing words with you since you appear to know everything. You must be "the one" that every field of pilots experiences. My reply was in regards to receiver part as the subject was. I gave you no cause to flame me and I will not accept it. Go get a rise from somebody else who cares.

FLYBOY 03-31-2005 10:50 AM

RE: tx / rx question
 
If it has a module in the back of it, you can legally change that module to change the freq. You just can't change a crystal in the module.

I have sent them in before to be changed, but it has been a long time. The turn around on Futaba is usually really fast. The last time I sent something to them was a receiver I screwed up and they had it back in less than 15 days. It was nice, and because it was only a week old, it seems to me that they didn't even charge me, even though it was my screw up that hurt it. That was nice of them.

Flypaper 2 03-31-2005 10:51 AM

RE: tx / rx question
 
On the Futaba, all you need to do is replace the module in the back to change channels. All the RF goodies are in the module.

bruce88123 03-31-2005 11:09 AM

RE: tx / rx question
 
Of course not all of the Futaba's have modules. But I imagine most know that. It would certainly make life easier.

piper_chuck 03-31-2005 11:16 AM

RE: tx / rx question
 

ORIGINAL: BigSkyRCer
I am not the only one, who has done this out of "Lack of knowing" not trying to break the law. Period. I think Futaba/JR, etc, etc, should list this warning on each TX crystal they sell, most people do not know this, as we all do not work on radios and deal with the FCC.
It is clearly stated in the Futaba manuals that transmitter crystals can only be changed by an authorized service center. It's also been discussed here many times and almost every time, one or more people make it obvious that they knew what they were supposed to do, but changed the crystal on their own anyway. I do agree that there should be clear instructions provided with the transmitter crystals.

Edit: forgot to mention, it's also been mentioned several times that hobby shop owners, who DID know better STILL advised customers to change them on their own.

jcankur 03-31-2005 11:36 AM

RE: tx / rx question
 

ORIGINAL: piper_chuck
Edit: forgot to mention, it's also been mentioned several times that hobby shop owners, who DID know better STILL advised customers to change them on their own.
Yes, Chuck, trying to sell the radio which is on a different channel than the buyer already uses - they're concerned about their profit ONLY not about the buyer and other RC-ers who may suffer the consequences.

BTW a radio which is not retuned after a crystal change may shoot down a plane using an adjacent frequency channel while flying perfectly fine the plane on the same channel.

-pkh- 03-31-2005 01:02 PM

RE: tx / rx question
 
I was flying my foamy yesterday, and when I did a low pass in front of the flight line, I got some severe glitches... a buddy of mine was next to me with an illegally retuned TX. Was it his TX, or was it my crappy feather RX, or a combination of both... I'll never know for sure! I do know that when I flew without him next to me with his TX, it flew fine! When I landed it, an severe aileron glitch hit, flip it sideways, and snapped my stick fuse on the foamy... nothing an hour and $2 worth of materials can't fix, but I'd hate to cause more severe damage to someone else's plane because I was too cheap to retune my radio properly...


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