Frequency change in a 9303

[tracerbob]

Three other people at our flying field are on the same channel (56)as I and I'm considering swapping out the crystals to either one channel up or down so I don't have to chase down the frequency pin all the time. I do this all the time with my R/C boats no problem. So I look in the manual to see what it sez and basically they state oh no don't do that! Only a qualified tech can only do it. Come on! Have any of you swapped out the cristals in a 9303 with no ill effect?

[Peter]

yep . ( but we have to get the module recertified here in Aus . )

or get a synthesised module for it ......even easier !!

[Pinecone]

It is against FCC regulations in the US. Do so and crash and hurt someone, you may not like the results in court. Like wanton disregard of Federal regualtions, negligence, etc.

Will it work, yeah, but in the US today, you may be in for a very bad ride.

I agree, buy the synthesized module and be done with crystals.

[WayneBrown]

I've done it with no problems numerous times.
Now I'm all synthesized, and don't worry about it.
Range check your gear prior to flight.

[kgfly]

Wait a month and get one of these instead, no more worries: http://www.xtremepowersystems.net/

[WayneBrown]

yeah, like I'm going to trust my $1200 kit to that.. :badair:

[kgfly]

Why not Wayne ? Just because it's new and you want to see it proved by others or do you have some other insight ?

[WayneBrown]

I've been a paying customer (read BETA tester) for several new products to the market, and don't enjoy the rebuild, crash, rebuild aspect of the hobby that much.
It's almost acceptable to fly a machine into the ground yourself, but the helpless feeling you get when you have no control really sucks.

[kgfly]

Well I did say "wait a month" as I think you will see a lot of feedback (hopefully good, maybe bad) about this very attractive new solution in that time (maybe 2 months, cannot be sure). If I was in tracebob's shoes I'd go with XPS for sure. Different strokes... :wink:

[BarracudaHockey]

There's more to it than crashing yours or someone elses model (more likely) doing illegal freqency swaps.

We are free loading on the band between channels used by high paying commercial customers. If they cause interference with us nobody will likely care, but cause problems for them and you will find out all about what the FCC can do.

Will you get away with it more often than not? Yes probably. Is it a good idea? No, probably not. If you arent going to be using it for a week or so send it to radio south, let them do it legally, tune it up, clean the stick pots and give the radio a once over.

[HeliDan]

Interesting. What about changing the crystals on gear when it is right out there for ya? Some of my lower end radios as well as my car transmitters and receivers have the crystal right out in front of you. I thought that was to make changing channels more easy? Also, why do the hobby shops sell the crystals then? :?:

Thanx for you help

[BarracudaHockey]

Also, why do the hobby shops sell the crystals then?

Because there's people with the right equipment that can verify output bandwidth and power levels making it legal to change transmitter crystals.

How fast will your car go? Does that make it legal?


What about changing the crystals on gear when it is right out there for ya

There's usually a dab of hot glue or something similar to conform to the "freqency determining components shall not be user accessable" legal drivel.

[WayneBrown]

on gear frmo the 70's and early 80's, I think this would hold truer than the present.
I was around for the 'big change' that prompted the gold stickers on the transmitters, back when AM was on the decline, and FM was just really beginning.
Our latest radio gear is narrow band enough not to bleed into adjoining channels enough to cause adverse reaction.
You still 'should' send your gear in for tuning, however.

[BarracudaHockey]

Yep me too, my first Futaba 6 channel radio was on Brown and White. You could also turn your tv to the right channel and make sure everything was transmitting correctly by watching the bars on the screen.

[RCHeliJim]

The Spektrum DX7 will be out soon - no more channel worries for me :D:D:D:D

Soon enough, threads like this will be a thing of the past.

[kgfly]

The Spektrum DX7 will be out soon - no more channel worries for me :D:D:D:D

Soon enough, threads like this will be a thing of the past.

Yup :D

[tracerbob]

Are the FCC rules different for 75Mhz radios? It's standard practice to have alternate frequencies when you go boat racing at a IMPBA or NAMBA sactioned event. So what If I'm breaking the some FCC regulation. What are they going to do, drive up to my flying field with a truck full of storm troopers, rough me up and drag me off to Gitmo? I don't think so. All I want to do is get in more flying time. :arggg: BTW, How many portable phones and minicam transmitters are on 2.4 Ghz? All of mine are, along with my wireless headphones.

[kgfly]

BTW, How many portable phones and minicam transmitters are on 2.4 Ghz? All of mine are, along with my wireless headphones.

Yup and shouldn't be any problem at all. That's part of the benefit of Spread Spectrum, *much* more efficient use of spectrum to allow multiple users to share the band. The ISM band is 80MHz wide and you can have hundreds of simultaneous connections at once. To any one connection, the others just look like noise. For very high bandwidth connections like 54Mb/s WiFi this can reduce range or throughput. For R/C applications with tiny data rates of the order of 250kb/s, the noise tolerance is very high indeed without significant degradation.

I am aware of a small number of interference problems reported with Spektrum DX6 setups where a video downlink tx was located next to the AR6000 Rx AND the video tx was turned on after the Rx. If it is turned on beforehand there is no problem since the Spektrum will detect it and select a lower noise channel or not initialise at all if the noise level is extreme. Even in many of these cases the problem was alleviated by moving the downlink tx away from the Rx. I operate my Spektrum right next to my WiFi laptop and cordless phone when working on my heli all the time without ever a single glitch.

There has been massive amounts of testing of Spektrum 2.4GHz systems in all kinds of challenging RF situations and it has performed outstandingly well. The XPS system is new and is being tested, but I am optimisitic that it too will prove much more robust, reliable and safer than legacy 27/35/36/45/72MHz FM (PPM or PCM) systems.

[BarracudaHockey]

Heres some reading from CFR47 Part 95 Personal Radio service.
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.)

(b) If the FCC finds that you have violated any section of the

Communications Act or the FCC Rules, you may be ordered to stop whatever

action caused the violation. (See section 312(b) of the Communications

Act.)

(c) If a federal court finds that you have willfully and knowingly

violated any FCC Rule, you may be fined up to $500 for each day you

committed the violation. (See section 502 of the Communications Act.)

(d) If a Federal court finds that you have willfully and knowingly

violated any provision of the Communications Act, you may be fined up to

$10,000, or you may be imprisoned for one year, or both. (See section

501 of the Communications Act.)



There's more

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.)


And
R/C transmitter (see R/C Rule 9) must be made in accord with the

Technical Regulations (see subpart E). 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.

[BarracudaHockey]

The industry interpretation is.

Crystal swapping is illegal in any of the R/C bands. (excluding ham bands)
Module swapping and PLL tuning is good to go (pll= synth modules)
A drop of hot glue makes the crystal not user accessable
Anyone with the right training and equipment to verify output can work on the transmitter.
The FCC doesnt care about recievers, only what you do with the transmitter.

There are no commercial users in the 75mhz band so the likely hood that they will bother you is slim.

If you are unfortunate enough to be involved in an accident or cause one, and an investigation turns up the fact you were operating illegally, your insurace would likely kiss you goodbye.

[Pinecone]

And I do know someone who is out about $25K for illegal operation (his case was off channel and over power on CB), but they just MAY come get you.

[tracerbob]

Wow, did I open a can of worms or what! :shock:

[DavidH]

Crystal swapping is illegal in any of the R/C bands.


Not in the 50 mhz and 53 mhz band. You have to hold at least a Tech license to use those bands.

David

[BarracudaHockey]

Sorry I was refering to the non ham bands, 27mhz, 72mhz and 75 mhz.

50 and 53mhz are not regulated by the R/C provisions of CFR47 Part 95, they are covered under the ham rules, whatever they are.

[WayneBrown]

Wow, did I open a can of worms or what! :shock:
See what you started? :D :D