Go Back  RCU Forums > RC Airplanes > Beginners
 Frequency hogs >

Frequency hogs

Community
Search
Notices
Beginners Beginners in RC start here for help.

Frequency hogs

Thread Tools
 
Search this Thread
 
Old 03-10-2007 | 06:34 PM
  #26  
opjose's Avatar
 
Joined: Nov 2005
Posts: 12,624
Likes: 0
Received 0 Likes on 0 Posts
From: Poolesville, MD
Default RE: Frequency hogs


ORIGINAL: 2slow2matter

JR does not sell a 7 channel radio that is module based. Period.
Let's see;

My old X-347 has a module
My XP783 has a module
My 8302 has a module
And my 10X's have modules

All are interchangable.

The 7202 doesn't though.


Old 03-12-2007 | 09:48 PM
  #27  
Senior Member
My Feedback: (1)
 
Joined: Aug 2004
Posts: 2,424
Likes: 0
Received 0 Likes on 0 Posts
From: Springtown, TX
Default RE: Frequency hogs

Those radios are no longer offered by JR, so therefore, JR no longer produces a 7 channel radio that utilizes modules.
Also, the 7202 uses flash memory rather than a battery backup. The 6102 uses the battery. At least, that's what JR tells us.
Old 03-13-2007 | 06:12 AM
  #28  
B.L.E.'s Avatar
Senior Member
 
Joined: Aug 2005
Posts: 1,333
Likes: 0
Received 0 Likes on 0 Posts
From: Austin, TX
Default RE: Frequency hogs

If you are going to spend the extra money to get a radio with frequency modules, why not just get a 2.4 GHz radio and be done with it? I just bought a Spektrum DX7 a month or two ago and I am loving it!
Old 03-13-2007 | 08:45 AM
  #29  
CGRetired's Avatar
My Feedback: (1)
 
Joined: Sep 2004
Posts: 8,999
Likes: 0
Received 3 Likes on 3 Posts
From: Galloway, NJ
Default RE: Frequency hogs

Now you've done it. Re-opened up an old can of worms..

I too have the new Spektrum DX7 and have bought three receivers so far, and counting. I am changing over to this fine radio system. I still love and use my Channel 11 Airtronics RD8000, by the way, and it has all I need to fly with. The DX7 is equally capable and then some, with the addition of being totally safe at the field with others flying anything they darned well please. No modules, no frequency issues, no mess, no fuss. (Yes, we use a pin system and include 2.4GHz in our pin system as well as the 50 MHz frequencies, by the way. That way we know who is flying what.)

My only problem is remembering to raise the antenna on the RD8000 after using the DX7 for a while.. [:@] but I am getting over that little mistake after a few, well, "damaged" airplanes.

DS.
Old 03-13-2007 | 08:53 AM
  #30  
Senior Member
 
Joined: Oct 2004
Posts: 298
Likes: 0
Received 0 Likes on 0 Posts
From: Richmond, TX
Default RE: Frequency hogs


ORIGINAL: B.L.E.

If you are going to spend the extra money to get a radio with frequency modules, why not just get a 2.4 GHz radio and be done with it? I just bought a Spektrum DX7 a month or two ago and I am loving it!

Lets say you have 5 models. You don't want to invest a bunch of money to convert all of them to 2.4 at the same time. With a module radio, you can only convert them as you want to, and still only need one radio at the field. just pop the correct module in to fly the plane of choice.

Lets say you have a modle with retracts, smoke, flaps, doors on a seperat channel, and all other controls. From my counting that is 8 channels needed, an module 9303 would do the trick.

I am sure there are many other reasons, but for some the decision to just get a DX-7 is not easy.

I have just about decided to get a 6M instead of 2.4. There are only 2 other fliers at my field on 6M, so there are plenty of channels available and I really don't need to worry about interferance or how a new technology will work.
Old 03-13-2007 | 09:05 AM
  #31  
foosball_movie's Avatar
Thread Starter
Senior Member
 
Joined: Jan 2007
Posts: 432
Likes: 0
Received 0 Likes on 0 Posts
From: Denton, TX
Default RE: Frequency hogs

I read a couple of articles ( [link=http://www.robotmarketplace.com/marketplace_rc_radioDX7.html]here's one[/link] ) on the DX 7. This sounds perfect! No more asking if someone is on my channel. When I upgrade from my Hobbistar trainer, I think I'll pick up DX 7 as well. Will Futaba servos work with the DX-7 receiver?
Old 03-13-2007 | 11:45 AM
  #32  
 
Joined: Nov 2004
Posts: 11,703
Likes: 0
Received 1 Like on 1 Post
From: Memphis, TN
Default RE: Frequency hogs


ORIGINAL: foosball_movie

I read a couple of articles ( [link=http://www.robotmarketplace.com/marketplace_rc_radioDX7.html]here's one[/link] ) on the DX 7. This sounds perfect! No more asking if someone is on my channel. When I upgrade from my Hobbistar trainer, I think I'll pick up DX 7 as well. Will Futaba servos work with the DX-7 receiver?
Yes. Might have to take off the little alignment tab on the servo/extension plugs.
Old 03-13-2007 | 11:58 AM
  #33  
foosball_movie's Avatar
Thread Starter
Senior Member
 
Joined: Jan 2007
Posts: 432
Likes: 0
Received 0 Likes on 0 Posts
From: Denton, TX
Default RE: Frequency hogs

Does Futaba make a TX/RX that does the same thing as the DX - 7?
Old 03-13-2007 | 12:28 PM
  #34  
 
Joined: Nov 2004
Posts: 11,703
Likes: 0
Received 1 Like on 1 Post
From: Memphis, TN
Default RE: Frequency hogs

Not exactly the same thing.
http://www.towerhobbies.com/products/pdf/towj62web.pdf
note: this pkg is without servos. they have other packages with servos available
Old 03-13-2007 | 12:42 PM
  #35  
 
Joined: Jan 2007
Posts: 104
Likes: 0
Received 0 Likes on 0 Posts
From: Fulton, MO
Default RE: Frequency hogs

Now this is all new to me. Please bare with me on this as I am trying to understand.

So I show up to fly with my Vangaurd 6 channel FM system that I originally purchased on channel 42. When I arrive I see "Bob" is there and I know that he flys using channel 42. Okay that is fine, because when this issue came up I reviewed the club frequency list and ordered up three crystals sets that are either open or have limited use. If I have read this thread correctly it is illegal for me pull out a crystal set that corresponds with an open channel and swap the crystals in both the TX and RX at the field.

Is this exactly what this thread is saying?

I do not see anything wrong doing this. The transmitter still broadcasts on the 72 Mhz frequency all I have done is alter exactly where in that frequency the information is transmitted.

Old 03-13-2007 | 12:45 PM
  #36  
 
Joined: Jan 2007
Posts: 104
Likes: 0
Received 0 Likes on 0 Posts
From: Fulton, MO
Default RE: Frequency hogs

Why? In my radios the crystal is right there on the back with a simple cover over it and a number. The same applies for the RX. All I need is a small screw driver and a set of needle nose pliers to change the crystals. All I need to remember to do is put the stickers on the covers so I know the channels.


ORIGINAL: bruce88123

You do NOT need a NEW transmitter. You can have an authorized service center change the crystal for you and perform any necessary retuning/checks required. First step is to poll your club to find out what channels are in use so you can request a currently unused channel or a more lightly used channel.
It IS legal for YOU to change RX crystals and you can do this yourself. One condition exists on this IF using Futaba radios. Most of their RX are Hi/Lo band segregated and crystals must be swapped within the same "range" of the band. If you move accross the band you should also send the RX in for retuning. Futaba's latest RX do not have this limitation.
Old 03-13-2007 | 12:59 PM
  #37  
sfsjkid's Avatar
 
Joined: Dec 2003
Posts: 592
Likes: 0
Received 1 Like on 1 Post
From: fremont, CA
Default RE: Frequency hogs

Yeah, the crystal setup is pretty misleading, comes from trying to make a common case for all of the world? FCC does not allow this in the US, possibly due to our closer channel spacings(?), You'll note that there is a spot of glue that supposedlly prevents us from swapping crystals, but generally no mention in manuals. I have seen 2 cases of interference caused by TX crystal swapping.

This question is so "popular" RCG has a sticky in their radio section.

http://www.rcgroups.com/forums/showthread.php?t=94580
Old 03-13-2007 | 01:00 PM
  #38  
RCKen's Avatar
RCU Forum Manager/Admin
My Feedback: (9)
 
Joined: Jul 2002
Posts: 28,236
Likes: 0
Received 31 Likes on 27 Posts
From: Lawton, OK
Default RE: Frequency hogs

Yes, you are absolutely correct. It is illegal for users in the United States to change the crystals in their transmiiters. This must be done by an authorized repair shop because the output frequency must be verified and adjusted if needed.

I understand that you crystal is easy to access for you and this is confusing. The reason for this is that these radios are sold worldwide, and it's only illegal in the US to change the crystal. The are not going to redesign the case just for sales in the US. This is why the crystal is easy to access on your radio.

If I remember correctly the fine for changing these out if caught is $10,000

Ken
Old 03-13-2007 | 01:03 PM
  #39  
RCKen's Avatar
RCU Forum Manager/Admin
My Feedback: (9)
 
Joined: Jul 2002
Posts: 28,236
Likes: 0
Received 31 Likes on 27 Posts
From: Lawton, OK
Default RE: Frequency hogs

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.

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]

[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]

[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]
Old 03-13-2007 | 01:08 PM
  #40  
CGRetired's Avatar
My Feedback: (1)
 
Joined: Sep 2004
Posts: 8,999
Likes: 0
Received 3 Likes on 3 Posts
From: Galloway, NJ
Default RE: Frequency hogs

Unfortunately, the manufacturers made it to easy to simply go ahead and change the crystals out. The bad part of this is the liability that is assumed once you change the TX crystal. If it is off frequency (It is not simply a place holder, the actual transmit frequency is changed and must be centered on that frequency not on the left or right of that center frequency) it will intefere with the adjacent frequency. It also could 'spatter' over other bands if it is not done correctly.

When they (radio shops like the manufacturer or Radio South for instance) swap out the TX crystal, they will check the output with a spectrum analyzer and see where the center frequency is and adjust it accordingly (if needed). Most systems use a phase lock loop system that digitally locks the frequency on center. What can be a problem is if you have a crystal that is problematic, and you will never know it until it causes problems, it could spill over to another channel and cause that channel to be corrupt. This will cause someone on that channel to have some serious problems.

So, you cannot just swap transmitter crystals out. Receiver crystals, on the other hand, do not transmit anything (for all practical purposes). So, if it does not work you will know it right away, or if it is not exactly right, your range check will fail. Easy to tell. Not so with the transmitter.
Old 03-13-2007 | 01:16 PM
  #41  
 
Joined: Jan 2007
Posts: 104
Likes: 0
Received 0 Likes on 0 Posts
From: Fulton, MO
Default RE: Frequency hogs

Thanks for all the information.

Old 03-13-2007 | 01:34 PM
  #42  
 
Joined: Nov 2004
Posts: 11,703
Likes: 0
Received 1 Like on 1 Post
From: Memphis, TN
Default RE: Frequency hogs

We operate in a VERY tight frequency environment in the U.S. Tighter than overseas. It would be too easy to interfere not just with another pilot but TV stations and other people who have PAID for the right to a clean/clear signal.
Old 03-13-2007 | 01:42 PM
  #43  
foosball_movie's Avatar
Thread Starter
Senior Member
 
Joined: Jan 2007
Posts: 432
Likes: 0
Received 0 Likes on 0 Posts
From: Denton, TX
Default RE: Frequency hogs

I must be missing something here. Why would someone stick with a FM crystal dependent transmitter when broad spectrum transmitters are available and cost around the same price?
Old 03-13-2007 | 01:53 PM
  #44  
chopper man's Avatar
Senior Member
 
Joined: Feb 2004
Posts: 801
Likes: 0
Received 0 Likes on 0 Posts
From: Pooler, GA
Default RE: Frequency hogs


ORIGINAL: foosball_movie

I must be missing something here. Why would someone stick with a FM crystal dependent transmitter when broad spectrum transmitters are available and cost around the same price?
It must be nice to extra cash laying around
I'm lucky to have the FM radio.
chopper man
Old 03-13-2007 | 01:59 PM
  #45  
sfsjkid's Avatar
 
Joined: Dec 2003
Posts: 592
Likes: 0
Received 1 Like on 1 Post
From: fremont, CA
Default RE: Frequency hogs

I've made the switch to SS on my cars, which was easy since I only have a couple. Now when it comes to planes, well I'd have to switch out 15~20 RX's, some of which need more than 7 channels. 2.4ghz does prevent shootdowns, but my feeling is that the band was choosen due to FCC regulations and low cost, easily available 2.4gHz modules made for modems, wi-fi etc., though this is not true of Futaba, and dealing with multiple antennas, albiet very short, necessitated by directionality and blocking issues. Also, the skeptic in me wonders where all of this will be in say 5 years, when as we see more and more things using 2.4gHz (I'm not talking just r/c here). Remember phones on 900mHz? Don't get me wrong, like I said I've made the switch in my cars, but my "old" 72mHz equipment is reliable enough to make it hard to justify going out and spending a grand or two switching out RX's right off.

BTW I do have a synthesized TX which allows me to pick any 72mHz frequency, allowing me to pick an open frequency. I though it would be a great feature to have but if someone shows up later the frequecy I've choosen for the day, a lot of times I won't switch. When I first started out, I was doing flight after flight, but have found that I enjoy the people at the field also, I've met a lot of good people sharing frequencies. As I've gone bigger (.90cu-in +), I find if I'm not pacing myself I can easily go thru a gallon or more of fuel in a day, so BS keeps me out of the poor farm also
Old 03-13-2007 | 02:00 PM
  #46  
foosball_movie's Avatar
Thread Starter
Senior Member
 
Joined: Jan 2007
Posts: 432
Likes: 0
Received 0 Likes on 0 Posts
From: Denton, TX
Default RE: Frequency hogs

It must be nice to extra cash laying around
True. However, is the trend heading away from FM crystal channel based TX/RX systems? If I was to start from scratch and buy a new plane and a new TX, why would I want a FM crystal based TX? From what I've seen, the DX-7 or similar system is the way to go.
Old 03-13-2007 | 02:29 PM
  #47  
 
Joined: Nov 2004
Posts: 11,703
Likes: 0
Received 1 Like on 1 Post
From: Memphis, TN
Default RE: Frequency hogs

Some of the "INTRODUCTORY" 4 channels are still cheaper. It's getting harder and harder to justify NOT going the extra mile but MANY of the beginners are on a shoestring budget and looking to save every penny they can.

It's an individual choice. That's why we try to tell you your options (like a menu) and let YOU choose. Hamburger or T-Bone. Either way, you eat (or fly).
Old 03-13-2007 | 02:54 PM
  #48  
sfsjkid's Avatar
 
Joined: Dec 2003
Posts: 592
Likes: 0
Received 1 Like on 1 Post
From: fremont, CA
Default RE: Frequency hogs

Good point Bruce, in fact I almost do a victory dance when a beginner shows up with a 9c and we don't have to match trims or throws with the buddy box.

Also, as I aluded to one post earlier, 2.4gHz is a new technology, and while it may be t-bone and for the vast majority of flyers, there have been several crash incidents posted on the various forums. More disconcernting is the fact that our field had had three...
Old 03-13-2007 | 03:31 PM
  #49  
 
Joined: Nov 2004
Posts: 11,703
Likes: 0
Received 1 Like on 1 Post
From: Memphis, TN
Default RE: Frequency hogs

I don't know about Spektrum but Futabas manual has several cautions about TX antenna positioning. Might be a good idea to give THEIR manual a read. MIGHT pick up some additional info. I know you can download it at the Tower site.
Old 03-13-2007 | 03:55 PM
  #50  
Junior Member
 
Joined: Mar 2007
Posts: 2
Received 0 Likes on 0 Posts
From: jax. beach, FL
Default RE: Frequency hogs

yes you can change channels on your transmitter. I have a jr10x and all I have to do is change the module in the back and change my rx channel and im ready to go


Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service

Copyright © 2026 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.