HobbyKing.com New Products Flash Sale
Reply
Thread Tools
Old Mar 13, 2006, 12:56 AM
Paint fixes everything.
Raleigh, NC
Joined Feb 2006
52 Posts
Question
How do you change radio transmitters?

I have a Futaba sky sport four radio that I would like to use for my CX, but switching th crystals did not work. Why is this? Does it have to do with the four in one reciever?
volksdad is offline Find More Posts by volksdad
Reply With Quote
Sign up now
to remove ads between posts
Old Mar 13, 2006, 01:09 AM
Coaxially Fixated
copperclad's Avatar
Rochester N.Y.
Joined Oct 2005
1,899 Posts
hi
i think you just need a single conversion crystal for the RX ( 4 in 1 ) that matches your TX channel , i could be all wet , but i am guessing your sky sport X-tal was a dual conversion RX , dana

PS: did you try putting the BCX TX X-tal in the sky sport TX , or did you try to put the sky sport RX X-tall in the 4 in 1
copperclad is offline Find More Posts by copperclad
Reply With Quote
Old Mar 13, 2006, 01:43 AM
Paint fixes everything.
Raleigh, NC
Joined Feb 2006
52 Posts
I took the x-tal out of the radio that came with the bcx and put it in the other (sky sport four) radio transmitter. The 4 in one would not go green, it stayed red.

Are you saying that i should switch the crystals on the recievers? or thaat i need a new set of xtals to do this?

Whats a dual vs single conversion crystal?

FYI the sky sport is a fairly old radio... At least 5 years, maybe 8! but it was a nice one when it was bought.
volksdad is offline Find More Posts by volksdad
Reply With Quote
Old Mar 13, 2006, 08:07 AM
Coaxially Fixated
copperclad's Avatar
Rochester N.Y.
Joined Oct 2005
1,899 Posts
hi volksdad

i think you will need to switch X-tals in both the RX and the TX , they both have to be on the same channel

and just for your information

there are a mess of things that can be different

positive or negative shift

single or dual conversion

AM or FM

72mhz or 49 mhz

and there are others like SPCM vs PPM

first is shift JR and airtronics are positive shift and won't work with futaba , futaba is negative shift

and as i understand a single conversion RX needs a single conversion X-tal , so a single conversion X-tal on channel 39 is a slightly different frequency than a dual conversion X-tal on channel 39

some older radios were AM and most new stuff is FM

and there are ground VS air frequencies

i could be wrong but i think the BCX TX is negative shift like your futaba sky sport so the sky sport should work , remember both the TX and the RX need to be the same channel so you will have to switch X-tals in both TX and RX

hope i haven't made this more confussing than it already is , dana
copperclad is offline Find More Posts by copperclad
Last edited by copperclad; Mar 13, 2006 at 08:44 AM.
Reply With Quote
Old Mar 26, 2006, 06:28 AM
Paint fixes everything.
Raleigh, NC
Joined Feb 2006
52 Posts
Quote:
Originally Posted by copperclad
i could be wrong but i think the BCX TX is negative shift like your futaba sky sport so the sky sport should work , remember both the TX and the RX need to be the same channel so you will have to switch X-tals in both TX and RX

hope i haven't made this more confusing than it already is , dana
Hey dana:

I've read this more than a couple of times, but I'm confused. If the recieving crystal in the stock transmitter is the the same as the one in the four in 1 (a matched set) then wouldn't i just have to switch the crystal out from the stock transmitter into the new transmitter (sky sport) that I want to use?
OR do I need to get a new set of crystals and install them one in the transmitter and one in the 4 in 1?

OH and thanks for explaining this. I appreciate it.
volksdad is offline Find More Posts by volksdad
Reply With Quote
Old Mar 26, 2006, 08:46 AM
Coaxially Fixated
copperclad's Avatar
Rochester N.Y.
Joined Oct 2005
1,899 Posts
hi

the RX crystal in the skysport could be dual conversion , the RX in the BCX needs to be single conversion

on the TX side it dosen't matter so leave the TX crystal the way it is and get a new single conversion crystal for the BCX RX that is the same frequency as the skysport TX

if you have a local hobby shop they should be able to help , don't feel bad this single , dual , positive , negative , fm , pcm , stuff is confusing at first , dana

or order a FM crystal set that is the same frequency as your skysport from here
http://www.horizonhobby.com/Products...arts%20Listing
and then just use the RX crystal in your BCX , so the skysport TX crystal would be the stock skysport crystal

but the BCX RX would have the new crystal installed
copperclad is offline Find More Posts by copperclad
Last edited by copperclad; Mar 26, 2006 at 09:02 AM.
Reply With Quote
Old Mar 26, 2006, 07:17 PM
Heli's rule!
dacaur's Avatar
Midvale, Utah, USA
Joined Mar 2005
9,332 Posts
all you need is a short single conversion crystal for the RX, that matches the channel of your TX. I personaly use a berg single conversion, I have heard of others using futaba and JR crystals with sucess, here is what you need http://www2.towerhobbies.com/cgi-bin...I=LXBFL1**&P=7 for channels 11-35 or http://www2.towerhobbies.com/cgi-bin...I=LXBFL2**&P=7 for channels 36-60


Technicaly, it is against fcc rules to change out the cystal in your TX....
dacaur is offline Find More Posts by dacaur
Reply With Quote
Old Mar 27, 2006, 01:20 PM
Registered User
FlyH2O's Avatar
Laceys Spring, AL
Joined Sep 2005
144 Posts
Futaba 9CAP Super

Here is how I setup my 9C. I have a synthesized module on my TX and set it to 52 to match my BCX. Parameters: ACRO (no need for a heli mode program) and PPM, Channels: 1 NORM, 2 NORM, 3 REV, and 4 REV, Trims: Throttle centered (if you trim it up to get hover the motors continue to run with throttle off) the rest minor adjustments to suit. It flies great hands off with no Issues. If you wanted you could add a little EXPO to flatten out the middle of the sticks when you’re first learning to hover it for a little finer control.

Larry O
FlyH2O is offline Find More Posts by FlyH2O
Reply With Quote
Old Mar 27, 2006, 04:18 PM
All Thumbs
Rooney7783's Avatar
College Station Texas, Home of the Fightin Texas Aggies
Joined Dec 2005
193 Posts
Technicaly, it is against fcc rules to change out the cystal in your TX....[/QUOTE]


It's not against the rules to change the crystals, it's against the rules to alter it for anything other than it's intended purpose. Otherwise no one in a legit hobby shop would sell tx crystals.
Rooney7783 is offline Find More Posts by Rooney7783
Reply With Quote
Old Mar 27, 2006, 07:48 PM
Electric Coolhunter
Thomas B's Avatar
United States, TX, Fort Worth
Joined Jun 2000
14,640 Posts
Quote:
Originally Posted by volksdad
Hey dana:

I've read this more than a couple of times, but I'm confused. If the recieving crystal in the stock transmitter is the the same as the one in the four in 1 (a matched set) then wouldn't i just have to switch the crystal out from the stock transmitter into the new transmitter (sky sport) that I want to use?
OR do I need to get a new set of crystals and install them one in the transmitter and one in the 4 in 1?

OH and thanks for explaining this. I appreciate it.
Get a single conversion crystal from GWS or JR that matches the existing frequency of your Skysport TX. It should work then. It worked for my Futaba conversion.

Your skysport rx crystal is a dual conversion crystal and will not work in the single conversion Esky 4 in 1.

The Esky radio is single conversion FM.
Thomas B is offline Find More Posts by Thomas B
RCG Plus Member
Latest blog entry: 2014 events and travel
Reply With Quote
Old Mar 27, 2006, 09:37 PM
Heli's rule!
dacaur's Avatar
Midvale, Utah, USA
Joined Mar 2005
9,332 Posts
gws crystals are mini, physically smaller, so wont work
dacaur is offline Find More Posts by dacaur
Reply With Quote
Old Mar 27, 2006, 09:46 PM
Electric Coolhunter
Thomas B's Avatar
United States, TX, Fort Worth
Joined Jun 2000
14,640 Posts
Quote:
Originally Posted by dacaur
gws crystals are mini, physically smaller, so wont work
Guess again.

Some GWS crystals are mini....but some are standard sized.

Check out the STANDARD SIZED GWS crystals at the bottom of this AeroMicro page:


http://www.aeromicro.com/Catalog/cry...2_products.htm
Thomas B is offline Find More Posts by Thomas B
RCG Plus Member
Latest blog entry: 2014 events and travel
Reply With Quote
Old Mar 27, 2006, 09:53 PM
Heli's rule!
dacaur's Avatar
Midvale, Utah, USA
Joined Mar 2005
9,332 Posts
Quote:
Originally Posted by Rooney7783
It's not against the rules to change the crystals, it's against the rules to alter it for anything other than it's intended purpose. Otherwise no one in a legit hobby shop would sell tx crystals.
just because you can buy it and put it in, doesn't make it ok... for example most states have lift laws that say you cannot lift your truck more than a certain amount, yet you can buy lift kits there designed for more than the legal limit...

The "official" reason hobby shops can sell TX crystals is that they are fragile and can break, so you need to be able to replace it... with the same channel

From futaba's website:
How do I change the frequency of my transmitter?
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.

From one of hitecs user manuals:
e. Changing Crystals
Changing crystal to avoid conflicts with other aircraft is possible where permitted. (You must check your local rules before doing so. For example in the US the FCC prohibits the changing of transmitter crystals on 72 and 27MHz).

from JR's website:
Can I change the crystal on my transmitter or module?
No, it must be returned to the authorized JR Service Center per FCC regulations.

From airtronics website:
Q. Can I change channels on my transmitter and receiver without re-tuning?
A. Radios equipped with frequency modules can be changed to another channel by replacing the tuned module with another tuned module. Radios not equipped with frequency modules can not legally be changed without re-tuning the radio to the specific channel. Not only is it against FCC regulations but more important it may shorten your range and/or cause interference with someone else's radio that could therefore cause personal injury.
dacaur is offline Find More Posts by dacaur
Reply With Quote
Old Mar 27, 2006, 10:40 PM
Heli's rule!
dacaur's Avatar
Midvale, Utah, USA
Joined Mar 2005
9,332 Posts
Quote:
Originally Posted by Thomas B
Guess again.

Some GWS crystals are mini....but some are standard sized.

Check out the STANDARD SIZED GWS crystals at the bottom of this AeroMicro page:


http://www.aeromicro.com/Catalog/cry...2_products.htm
i did not know that..
dacaur is offline Find More Posts by dacaur
Reply With Quote
Old Apr 01, 2006, 09:12 AM
Paint fixes everything.
Raleigh, NC
Joined Feb 2006
52 Posts
Quote:
Originally Posted by Thomas B
Get a single conversion crystal from GWS or JR that matches the existing frequency of your Skysport TX. It should work then. It worked for my Futaba conversion.

Your skysport rx crystal is a dual conversion crystal and will not work in the single conversion Esky 4 in 1.

The Esky radio is single conversion FM.

First, thanks to all who've chimed in and offered their experience.

I went to my lhs and showed them this thread and the radio guru there quoted me like $50.00, and also said that it might not work. He explained that i had to buy a new Xtal for my reciever, AND a new Xtal for my transmitter.

he explained that the skysport 4 is a good radio that works with dual conversion xtals and that the bcx system is single conversion, therefore id need to buy two.

If i undrstand you correctly it is possible to use single conversion xtals in a dual conversion tx, but dual conversion xtals wont work in a single conversion tx.

SO i just have to buy one xtal thay matches both the channel and frequency of my bcx rx, and make sure that its single conversion, right? I'm gonna try that link you posted with standard sized GWS xtals....
volksdad is offline Find More Posts by volksdad
Reply With Quote
Reply


Thread Tools

Similar Threads
Category Thread Thread Starter Forum Replies Last Post
Discussion How do you test radio range before you fly? BowerR64 Radios 3 Aug 14, 2007 08:47 PM
Discussion How do you change hole on servo arm?? mcf34 Coaxial Helicopters 1 Feb 14, 2007 03:05 PM
Suggestion How do you change your name? J.E. Johnson Site Suggestions / Complaints 1 Apr 12, 2006 08:28 AM
Pinion Gears- how do you change them? Dadzilla-5 Power Systems 1 Jan 24, 2005 04:31 PM
How do you change under your user name ?? Mopar92 Life, The Universe, and Politics 2 Dec 09, 2003 02:43 PM