Illegal Xstal Change

[HeliDan]

I remember reading in this forum that it is illegal to change the crystals in a radio/receiver because they must also re-align the system. On readyheli.com, they mention the ability to change the crystals in the radio to fly when you current freq is in use.

I'm confused.

:fly

[Pinecone]

In the US, the FCC regs say that you cannot swap crystals in transmitters. You can swap MODULES. So radios that use modules (JR 9303, Futaba 9, Hitec Eclipse 7 and Optic 6, etc) you can swap the modules, but not the crystals in the modules.

In other countries you can legally swap crystals. I know many people in the US do so, but personally it doesn't pass my legal test. That is, would be happy trying to explain in court why you did that and that is had NOTHING to do with why your aircraft (heli or airplane) went and hit that person.l

[spork]

Pinecone is right. It's not legal in the U.S. But... I bought a 7CHP on ebay. He said he had it on CH 18. In fact it wasn't a CH 18 radio. He had stuck a CH 18 crystal in it. But I put it on the spectrum analyzer, and found that it was well within all specs for CH 18. So in this case I'd be happy to argue the case in court if it ever came to that.

[BarracudaHockey]

To add to what they correctly said, the FCC cares nothing about recievers, only transmitters.

The fine is something on the order of 10 grand per occurance if doing so interferes with a commercial user that complains and if they can track it to you, there's commercial freqencies between ours on the 72mhz band, thats why its illegal in the first place or as Pinceone said, you end up explaining yourself in the case of an accident.

Rick, since there's nowhere that I can find that defines a qualified tech Id say if you have the proper equipment, and the expertise to verify the equipment is within specs and you know what the specs are, you are probably a "qualified technician" since theres no license requirement that I'm aware of for repairing RC equipment.

[rkeith2]

General FCC Technician license and the proper equipment like a Motorola or IFR Service Monitor that is capable of seeing that the TX is on center frequency, the modulation is not too high and there is no spuriousout of band emissions. :glasses2:

[spork]

Rick, since there's nowhere that I can find that defines a qualified tech Id say if you have the proper equipment, and the expertise to verify the equipment is within specs and you know what the specs are, you are probably a "qualified technician" since theres no license requirement that I'm aware of for repairing RC equipment.

Crap! I thought I was being an outlaw. Living on the edge. :mrgreen:

General FCC Technician license and the proper equipment...

Maybe I'm an outlaw after all. I have a ham license, but I'm guessing that's not what you mean.

[BarracudaHockey]

I've been through the regs and couldnt find where it specified, not that I'm saying you are wrong but I've never been able to nail it down.

[MarkD]

Let me get this right and please correct me if I've got the wrong idea??

In the USA your're not allowed to say remove the freq module (FF9 for ex) then remove the crystal and put another then plug the module back into the Tx in to change which channel you are using??

If so where does the Futaba Sythesized module sit in this law

Seems very restrictive compared to the UK where we can just swap out crystals to an unused channel

[BarracudaHockey]

Synth is PLL tuned, you arent changing freqency determining components so they are fine.

You can change modules because it has the entire tunable rf section, you cannot swap crystals, either in the transmitter or a module.

Seems restrictive is a relative thing, outwardly yes. However when you consider that we are pretty much freeloaders in the band, and high paying commercial users are inbetween our channels, things like remote controlled cranes etc then it makes sense that we cannot cause these commercial users any interference.

This AFAIK doesnt apply to 50 mhz (ham band) and I dont think 27mhz

Are you going to
A. Cause a problem or insurance incident AND
B. Get caught?

Probably not. Is it a good idea to follow the law given the possible consequences? I think so but its up to whatever you can afford in fines and lawyer fees, for me I'd rather pay the 20 bucks to get a transmitter tuned and be done with it.

[MarkD]

I suppose it does make sense when you say there are other (high paying) users between channels which we don't get with the 35Mhz

I take it this is why the 2.4Ghz has taken off so well over there :D and not so over here

[Pinecone]

Yeap, FCC General ticket. Ham ticket for 50 MHz.

[johndoe25]

Yeap, FCC General ticket. Ham ticket for 50 MHz.

Pinecone, a no-code tech can be on 50 MHz or 6 meters.

[rkeith2]

Sorry guys I should have clarified a little =

Hams are encouraged and required to maintain their transmitters within spec.

Commercial applications require FCC lic'd technicians to "legally" adjust output networks and frequencies.
:smokin:

[Pinecone]

That's what I was saying. :)

And 50Mhz and 6m are the same thing. One by frequency, one by wave length. Like 2m or 144MHz or 440Mhz or 70cm, etc.

[rkeith2]

Meter Band Frequency Range and Use
160 meters 1800-2000 kHz ham radio
120 meters 2300-2498 kHz broadcasting
90 meters 3200 to 3400 kHz broadcasting
80 meters 3500 to 4000 kHz ham radio
60 meters 4750 to 4995 kHz broadcasting
49 meters 5950 to 6250 kHz broadcasting
41 meters 7100 to 7300 kHz broadcasting
40 meters 7000 to 7300 kHz ham radio
31 meters 9500 to 9900 kHz broadcasting
30 meters 10100 to 10150 kHz ham radio
25 meters 11650 to 11975 kHz broadcasting
22 meters 13600 to 13800 kHz broadcasting
20 meters 14000 to 14350 kHz ham radio
19 meters 15100 to 15600 kHz broadcasting
17 meters 18068 to 18168 kHz ham radio
16 meters 17550 to 17900 kHz broadcasting
15 meters 21000 to 21450 kHz ham radio
13 meters 21450 to 21850 kHz broadcasting
12 meters 24890 to 24990 ham radio
11 meters 25670 to 27990 kHz broadcasting, CB
10 meters 28000 to 29700 kHz ham radio

[Pinecone]

http://www.arrl.org/FandES/field/regulations/allocate.html#17

Ham Bans VHF and higher

6 M - 50.0 - 54.0 MHz

2 M - 144.0 - 148 MHz

1.25 M - 222.0 - 225.0 MHz

70 CM (or 0.7 M) - 420 - 450 MHz

33 CM - 902 - 928 MHz

and so forth up to 300 GHz.

And BTW 2.300 - 2.31 GHz and 2.39 - 2.45 Ghz are also ham bands.

[rkeith2]

Thx Terry -

Good info for all

[Pinecone]

There are a couple of great charts. Yaesu makes one off pretty much all the ham bands.

The other one I have from somewhere is pretty much the entire RF spectrum and what uses what parts, icnluding major users of shared bands. VERY cool. When I am home I will have to see if there is info on where it came from.

It is also funny, but in the ham world certain bands are refered to by frequency and otehrs by wave length. YOu talk of 6 m, and 2m, but 220 and 440 MHz. Know idea of why.

[matrix1171]

correct me if i'm wrong but, i thought it was illeagal to change bands(like 27mghz to 40 and so on)i also thought that only then would you have to realign the system. i run on the surface most of the time and we change CHANNELS all the time not freqs. just a question

[HeliDan]

correct me if i'm wrong but, i thought it was illeagal to change bands(like 27mghz to 40 and so on)i also thought that only then would you have to realign the system. i run on the surface most of the time and we change CHANNELS all the time not freqs. just a question

Well, we were originally talking about a freq change, not band change. And yes, apparently a freq change is illegal.

[matrix1171]

ok, so what your saying, changing to i different channel in a specifc band 27, 40, 72,75(the most popular 27and 75) and so on is illeagl. i'm asking because when i was racing rc cars at big events the entry forms requrie at least three different channels just trying to understand because it doesn't make sense to me... maybe i'm missing something :dontknow

[HeliDan]

ok, so what your saying, changing to i different channel in a specifc band 27, 40, 72,75(the most popular 27and 75) and so on is illeagl. i'm asking because when i was racing rc cars at big events the entry forms requrie at least three different channels just trying to understand because it doesn't make sense to me... maybe i'm missing something :dontknow

I am not sure about changing bands, but I doubt these radios are designed for a band change, if they use crystals.

It is illegal to change the crystal in the transmitter without going through a licensed radio tech. :arggg:

[matrix1171]

ok, i could believe that if the crystal was hard wired to the board and sealed but, these
crystals are removedable. bands, however, are not they require a licensed radio tech beacause the band width is tuned.

[spork]

ok, i could believe that if the crystal was hard wired to the board and sealed but, these
crystals are removedable. bands, however, are not they require a licensed radio tech beacause the band width is tuned.

I know it sounds crazy, but it is definitely illegal to change our crystals in our transmitters unless you have a qualified radio tech check and/or re-tune the radio to insure it is in spec. This is true for any crystal change, even within bands - even within the "low" or "high" portion of the band (as Futaba used to define it). That's why many of the radios have removable RF modules. You may change the entire tuned RF module in the field.

I did change my crystal in my 7CHP, and then checked it out on the spectrum analyzer. It was all well within spec.

[Pinecone]

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, Sec. Sec.
95.209 and 95.210.)

Changing a crystal is NOT changing a plug in module that was certificated as part of the Tx.

And the reason why you don't change crystals:

g) Stations in the 72-76 MHz range are subject to the condition
that inteference will not be caused to the remote control of industrial
equipment operating on the same or adjacent frequencies or to the
reception of television transmissions on Channels 4 and 5. These
frequencies are not afforded any protection from interference due to the
operation of fixed and mobile stations in other services assigned to the
same or adjacent frequencies.

And what can happen if you do:

Sec. 95.218 (R/C Rule 18) What are the penalties for violating these
rules?

(a) If the FCC finds that you have willfully or repeatedly violated
the Communications Act or the FCC Rules, you may have to pay as much as
$10,000 for each violation, up to a total of $75,000. (See Section
503(b) of the Communications Act.)