AM Transmitters
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AM Transmitters
I bought a 4 channel airplane kit awhile ago, put it together and now I'm curious....
THe transmitter has a 27mhz crystal in it and the transmitter says "AM" on it. Does this mean that any crystal I put in there that it will only transmit on the AM frequency or is that specified by the cyrstal only?
The transmitter isn't bad or anything but I was wondering if I could use it to power other airplanes as long as I changed the crystal to a 72mhz with the appropriate matching channel for the receiver. It would save me a good 30-50 dollars that I could spend on servos, etc. on a new ARF package.
THe transmitter has a 27mhz crystal in it and the transmitter says "AM" on it. Does this mean that any crystal I put in there that it will only transmit on the AM frequency or is that specified by the cyrstal only?
The transmitter isn't bad or anything but I was wondering if I could use it to power other airplanes as long as I changed the crystal to a 72mhz with the appropriate matching channel for the receiver. It would save me a good 30-50 dollars that I could spend on servos, etc. on a new ARF package.
#2
RE: AM Transmitters
it is illegal to change crystals in transmitters,but that being said if you are on the 27 mhz band you could not change the cystal to work in the 72 mhz band two different animals.it is legal to fly on the 27 band but it is shared with boats,cars and cb
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RE: AM Transmitters
Hmm. Well the transmitter has the crystal in the front with a pullout tab just like you would from a regular JR kit or something like that. I have another plane that had a 2 channel transmitter with a removable crystal and I swap the crystals to control either one plane or the other with this 4 channel transmitter on the 27mhz AM band.
#4
RE: AM Transmitters
do a little research and you will find that it is illegal to change crystals in a tx and that by doing so can cause the reduction of range to your model and rf noiise on another frequency.but hey what do Iknow I've only been doing this since 1970
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RE: AM Transmitters
I’m not denying anything that you’re saying. But I guess that means that for every new plane that I decide to purchase, I have to cannibalize my old system and put it in the new one or if I get a new set of equipment that I have to have a separate transmitter for every single plane I buy? I think some transmitters have channel selectors don’t they?
#6
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RE: AM Transmitters
It is indeed illegal to change the crystals in an RC transmitter in the US. It is punishable by up to $10,000 per incident.
In addition, you don't want to fly an RC plane on a 27 Mhz radio because there are too many other things that can interfere with it. Many of the "cheap" RC toys out there are on 27 Mhz and you never know where they are. It's just too risky IMHO.
If you are interested in the full text of the regulations concerning this matter they can be found at:
[link=http://www.access.gpo.gov/nara/cfr/waisidx_04/47cfr95_04.html]FCC Title 47, Part 95 - Personal Radio Services[/link]
Copied from Futaba's website
Copied from FCC regulations concerning this issue
Ken
In addition, you don't want to fly an RC plane on a 27 Mhz radio because there are too many other things that can interfere with it. Many of the "cheap" RC toys out there are on 27 Mhz and you never know where they are. It's just too risky IMHO.
If you are interested in the full text of the regulations concerning this matter they can be found at:
[link=http://www.access.gpo.gov/nara/cfr/waisidx_04/47cfr95_04.html]FCC Title 47, Part 95 - Personal Radio Services[/link]
Copied 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. 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.
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.
Copied from FCC regulations concerning this issue
[Code of Federal Regulations]
[Title 47, Volume 5]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR95.221]
[Page 539]
TITLE 47--TELECOMMUNICATION CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION (CONTINUED)
PART 95_PERSONAL RADIO SERVICES--Table of Contents
Subpart C_Radio Control (R/C) Radio Service
Sec. 95.221 (R/C Rule 21) How do I have my R/C transmitter serviced?
(a) You may adjust an antenna to your R/C transmitter and you may make radio checks. (A radio check means a one-way transmission for a short time in order to test the transmitter.)
(b) You are responsible for the proper operation of the station at all times and are expected to provide for observations, servicing and maintenance as often as may be necessary to ensure proper operation. Each internal repair and each internal adjustment to an FCC certificated 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.
(c) Except as provided in paragraph
(d) of this section, each internal repair and each internal adjustment of an R/C transmitter in which signals are transmitted must be made using a nonradiating (``dummy'') antenna. (d) Brief test signals (signals not longer than one minute during any five minute period) using a radiating antenna may be transmitted in order to:
(1) Adjust a transmitter to an antenna;
(2) Detect or measure radiation of energy other than the intended signal; or
(3) Tune a receiver to your R/C transmitter.
(Secs. 4(i) and 303(r), Communications Act of 1934, as amended, 47 U.S.C. 154(i) and 303(r), and sec. 553 of the Administrative Procedures Act, 5 U.S.C. 553) [48 FR 24890, June 3, 1983, as amended at 49 FR 20673, May 16, 1984; 63 FR 36610, July 7, 1998]
[Title 47, Volume 5]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR95.221]
[Page 539]
TITLE 47--TELECOMMUNICATION CHAPTER I--FEDERAL COMMUNICATIONS COMMISSION (CONTINUED)
PART 95_PERSONAL RADIO SERVICES--Table of Contents
Subpart C_Radio Control (R/C) Radio Service
Sec. 95.221 (R/C Rule 21) How do I have my R/C transmitter serviced?
(a) You may adjust an antenna to your R/C transmitter and you may make radio checks. (A radio check means a one-way transmission for a short time in order to test the transmitter.)
(b) You are responsible for the proper operation of the station at all times and are expected to provide for observations, servicing and maintenance as often as may be necessary to ensure proper operation. Each internal repair and each internal adjustment to an FCC certificated 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.
(c) Except as provided in paragraph
(d) of this section, each internal repair and each internal adjustment of an R/C transmitter in which signals are transmitted must be made using a nonradiating (``dummy'') antenna. (d) Brief test signals (signals not longer than one minute during any five minute period) using a radiating antenna may be transmitted in order to:
(1) Adjust a transmitter to an antenna;
(2) Detect or measure radiation of energy other than the intended signal; or
(3) Tune a receiver to your R/C transmitter.
(Secs. 4(i) and 303(r), Communications Act of 1934, as amended, 47 U.S.C. 154(i) and 303(r), and sec. 553 of the Administrative Procedures Act, 5 U.S.C. 553) [48 FR 24890, June 3, 1983, as amended at 49 FR 20673, May 16, 1984; 63 FR 36610, July 7, 1998]
[Code of Federal Regulations]
[Title 47, Volume 5]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR95.222]
[Page 539-540]
TITLE 47--TELECOMMUNICATION
CHAPTER I--FEDERAL COMMUNICATIONS
COMMISSION (CONTINUED)
PART 95_PERSONAL RADIO SERVICES--Table of Contents
Subpart C_Radio Control (R/C) Radio Service
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.)
[48 FR 24894, June 3, 1983, as amended at 63 FR 36610, July 7, 1998]
[Title 47, Volume 5]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR95.222]
[Page 539-540]
TITLE 47--TELECOMMUNICATION
CHAPTER I--FEDERAL COMMUNICATIONS
COMMISSION (CONTINUED)
PART 95_PERSONAL RADIO SERVICES--Table of Contents
Subpart C_Radio Control (R/C) Radio Service
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.)
[48 FR 24894, June 3, 1983, as amended at 63 FR 36610, July 7, 1998]
[Code of Federal Regulations]
[Title 47, Volume 5]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR95.645]
[Page 561]
TITLE 47--TELECOMMUNICATION
CHAPTER I--FEDERAL COMMUNICATIONS
COMMISSION (CONTINUED)
PART 95_PERSONAL RADIO SERVICES--Table of Contents
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.
[53 FR 36789, Sept. 22, 1988. Redesignated at 61 FR 28769, June 6, 1996, and further redesignated at 61 FR 46567, Sept. 4, 1996; 63 FR 36610, July 7, 1998]
[Title 47, Volume 5]
[Revised as of October 1, 2004]
From the U.S. Government Printing Office via GPO Access
[CITE: 47CFR95.645]
[Page 561]
TITLE 47--TELECOMMUNICATION
CHAPTER I--FEDERAL COMMUNICATIONS
COMMISSION (CONTINUED)
PART 95_PERSONAL RADIO SERVICES--Table of Contents
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.
[53 FR 36789, Sept. 22, 1988. Redesignated at 61 FR 28769, June 6, 1996, and further redesignated at 61 FR 46567, Sept. 4, 1996; 63 FR 36610, July 7, 1998]
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RE: AM Transmitters
So that being said, I would assume the idea is to just buy appropriate crystals for any receivers you pick up, yes? Thanks for the info. If the 27mhz band is that goofy as far as interference I may as well pick up a regular pack then.
#8
RE: AM Transmitters
but of course there's always the outlaws that will change the crystals in their transmitters. so who's to know. upgrade to fm and get a radio that will last you years to come. the futaba 6 ex is good.
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RE: AM Transmitters
Computer radios? Are those the ones that are on the 900-2.4mhz band? Not to waste your time, but could you perhaps reccomend me any certain computer models? Otherwise, yah I was looking at the Futaba packs or the GWS/JR ones specifically (6 channels so I can add stuff in a few years if I wanted to).
WHen you get a 6 channel transmitter, and the two extra channels are toggles, can you still link a servo to those say, if you wanted to create a "barndoor" system to drop bombs or a glider or parachute men, etc.?
WHen you get a 6 channel transmitter, and the two extra channels are toggles, can you still link a servo to those say, if you wanted to create a "barndoor" system to drop bombs or a glider or parachute men, etc.?
#11
RE: AM Transmitters
Here is an inexpensive 4 channel computer radio with 4 plane memory
http://www2.towerhobbies.com/cgi-bin...=LXKJD8**&P=SM
Basic 6 channel 72 MHz with 6 model memory
http://www2.towerhobbies.com/cgi-bin...=LXHYK7**&P=SM
Same radio in 2.4 GHz
http://www2.towerhobbies.com/cgi-bin...&I=LXPZT8&P=SM
The Spektrum DX7 since you asked http://www.horizonhobby.com/Products...ProdID=SPM2710
There are of course other brands that are just about as good. I just know these better.
The 2 extra channels can be switches or knobs but you have the functions about right.
http://www2.towerhobbies.com/cgi-bin...=LXKJD8**&P=SM
Basic 6 channel 72 MHz with 6 model memory
http://www2.towerhobbies.com/cgi-bin...=LXHYK7**&P=SM
Same radio in 2.4 GHz
http://www2.towerhobbies.com/cgi-bin...&I=LXPZT8&P=SM
The Spektrum DX7 since you asked http://www.horizonhobby.com/Products...ProdID=SPM2710
There are of course other brands that are just about as good. I just know these better.
The 2 extra channels can be switches or knobs but you have the functions about right.
#12
My Feedback: (7)
RE: AM Transmitters
My suggestion: Go to your local flying site and ask what the most popular unit everyone is flying there. That way when you need help you have the same equipment. I have been an Airtronics man from the start and have to much invested to switch. I have three radios all computer versions. RD6000 and the 8000, I can fly a total of 18 different modelson these three. I do keep a log book in my flight box of the model and what radio it uses for safety reasons.
Most of the computer radios today re good and the extra channels are ther for your own imagination and workings. Candy drop, glider tow, bomb drop, flaps, retracts, what ever.
Spend the money upfront, you will be glad you did.
Jim
Most of the computer radios today re good and the extra channels are ther for your own imagination and workings. Candy drop, glider tow, bomb drop, flaps, retracts, what ever.
Spend the money upfront, you will be glad you did.
Jim
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RE: AM Transmitters
Great advice guys, thank you very much! Having plane memory looks like a huge advantage.
I haven't looked into much of what groups actually fly out where I am (I live in Southern California, out by Riverside and San Bernardino). It's hard enough for me to find an empty lot that has asphalt and/or grass (I'm lucky if I find a single school that's open enough or even accessable). I'm not sure if it's the culture for everything to be locked down or unavailable out here but it sure seems unfriendly Dirt lots suck because they're way too hot and landing is impossible unless I'm flying my little EPP planes.
I haven't looked into much of what groups actually fly out where I am (I live in Southern California, out by Riverside and San Bernardino). It's hard enough for me to find an empty lot that has asphalt and/or grass (I'm lucky if I find a single school that's open enough or even accessable). I'm not sure if it's the culture for everything to be locked down or unavailable out here but it sure seems unfriendly Dirt lots suck because they're way too hot and landing is impossible unless I'm flying my little EPP planes.
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RE: AM Transmitters
hi
got some bad news for you. it is illegal to change crystals in an rc transmitter except by a shop where it can be realigned.
also 27 mhz is not the best frequency to fly on due to possible CB radio interference.
good luck and happy flying
pt19 flyer
got some bad news for you. it is illegal to change crystals in an rc transmitter except by a shop where it can be realigned.
also 27 mhz is not the best frequency to fly on due to possible CB radio interference.
good luck and happy flying
pt19 flyer