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HelicopterRadio - Servo - Gyro - Gov - Batt › FUTABA Low band crystals in a High Band system
01-29-2007 12:36 AM  10 years agoPost 1
Dood

rrProfessor

Wescanson

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I picked up a used Futaba radio with a TX module on "high band" channel 50. 1028 PCM.

Everything I have owned prior to this, is "low band" equipment on channel 29.

I have an extra channel 29 crystal that I want to put in the TX.
I understand it will work, but what drawbacks are there to doing so?

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01-29-2007 12:43 AM  10 years agoPost 2
Dood

rrProfessor

Wescanson

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Reply sent to me on a PM. Not sure if it is a joke or what. Perhaps someone who doesnt want to get flamed for being wrong?
it will work just as good as any other withthat x-stal!

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01-29-2007 04:11 PM  10 years agoPost 3
BarracudaHockey

rrMaster

Jacksonville FL

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Its illegal (in the US) to swap crystals in the module or transmitter. If you had a module then you could legally swap the whole thing which is the best way to do it.

High band/low band only effects recievers btw.

Andy
AMA 77227
http://www.jaxrc.com

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01-29-2007 04:37 PM  10 years agoPost 4
Dood

rrProfessor

Wescanson

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Thats interesting.

It's illegal to swap the crystal in a TX?

Why? They sell crystals. So what does a guy do when he has 7 Rx's all on one single channel, and he gets a TX on a different channel?

There is no tamper seal or anything on the transmitter module. Its curious why it would be ILLEGAL.
The crystal slides right out, just the same as the RX crystal.

So, could I QUOTE- UNQUOTE BUY a new Transmitter module with a different Crystal?

Who would kow the difference anyway?

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01-29-2007 04:55 PM  10 years agoPost 5
whirlyspud

rrKey Veteran

USA

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They sell gasoline and coke bottles and bed sheets, but they get kind of upset if you buy the gas, pour it in the bottles and add a strip from the blanklet to the opening of the bottle. Go figure.

The FCC does not like you changing the TX side because you probably have no way of checking that it remains in tune when you are all done. I'm sure that if you go ahead and do it anyway, you will not be the first. Like it or not though, it is the law. Like any law, the choice to follow it or not is up to you.

Mike

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01-29-2007 04:57 PM  10 years agoPost 6
heliguy

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Boulder, CO

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An old subject...

The following is copied from the Futaba FAQ's:

How do I change the frequency of my transmitter?

For a module unit: to change the frequency you simply remove the module and replace it with a module on the new channel. You can even change 'bands' (IE 72MHz to 75MHz). All radio frequency circuitry is in the module so there is no need to 'retune' after a module change. (However, the receiver cannot be similarly changed to change bands. If you go to a new band you MUST buy a new receiver on that band. Please see the note below regarding crystal changes, which is valid for ANY receiver where you are changing within one frequency band.) DO NOT attempt to change transmitter frequency by changing the crystal within the module. You must use a module which is properly tuned to the frequency desired.

For a unit with crystals: We CANNOT recommend changing crystals to a different frequency. Changing the crystal on your transmitter is illegal unless you have the proper license. The FCC has established guidelines for the modeler's safety and for the safety of spectators. For safety and FCC reasons we must request that both TX and RX be sent to the service center to ensure proper crystal change and retuning to the new frequency. Crystal based radios cannot be converted to another band without parts replacement, and may not be able to be converted at all. Certain radios can be converted, for example, from 72 to 75MHz. Please contact the service center for any other conversions.

The applicable Federal Regulation is as follows:

TITLE 47—TELECOMMUNICATION COMMISSION (CONTINUED)
PART 95—PERSONAL RADIO SERVICES

Subpart E—Technical Regulations
Sec. 95.645 Control accessibility.
(a) No control, switch or other type of adjustment which, when
manipulated, can result in a violation of the rules shall be accessible from the transmitter operating panel or from exterior of the transmitter enclosure.
(b) An R/C transmitter which incorporates plug-in frequency
determining modules which are changed by the user must be certificated 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.

Al

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01-29-2007 05:01 PM  10 years agoPost 7
BarracudaHockey

rrMaster

Jacksonville FL

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If you get caught for causing a problem its a 10 grand fine per occurance, if that problem involves an insurance claim its likely they would leave you high and dry due to making illegal mods to your transmitter.

There's high paying commercial users sandwhiched between our channels, cause them problems and they will come looking for you.

Andy
AMA 77227
http://www.jaxrc.com

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01-29-2007 09:46 PM  10 years agoPost 8
Dood

rrProfessor

Wescanson

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Thanks guys for that information I did not know.

So, anyone by chance have a Futaba ch. 29 TX module they want to trade for a ch. 50 module?

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HelicopterRadio - Servo - Gyro - Gov - Batt › FUTABA Low band crystals in a High Band system
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