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Reason for not upgrading to 2.4

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Old 05-03-2009, 01:50 PM
  #76  
cap10b
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Default RE: Reason for not upgrading to 2.4

All,
I want to chime in a little here only because I was over on the Hobby People site and listened to a 2.4 seminar that Mike Greenshields put on at the Expo 2009. Quote "just because 2.4 is here DOES NOT MEAN that suddenly 72 Mghz is bad" Mike goes on to say that 72 Mghz has served the industry well and will continue to serve us well. But try not to think of the new digital radios as RF stations but as computers.

The latency of the systems allows the mfg to update and build on a system not unlike Microsoft did on Windows. Where in the upgrades can go forward and be backward compatible at the same time. That's how these aftermarket Mfg's are able to make add
on systems for MODULE based radios and bring those systems up to 2.4.

Thinking of the radios as computers lets you know that not everyone needs nor wants a GAMERS COMPUTER, many wont ever use all
that functionality. Some will, just because they can afford the expense other won't because they have other plans for the money.

Either way when you look at this as a SYSTEM and not as a single one time piece of equipment it might make some more at ease that they can venture into 2.4 at their own pace and if they so choose back out and not be out a ton of money.

That seminar was very informative.

And a little tid bit of history I didnt know.........the fastest RC Radio in our industry is still a 1975 (72 Mghz FM) Kraft radio that was measured at .03 MS with a range of over 25,000 feet. I guess Phill Kraft really did know what he was doing.

jds

Old 05-03-2009, 05:10 PM
  #77  
rmh
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Default RE: Reason for not upgrading to 2.4


ORIGINAL: cap10b

All,
I want to chime in a little here only because I was over on the Hobby People site and listened to a 2.4 seminar that Mike Greenshields put on at the Expo 2009. Quote "just because 2.4 is here DOES NOT MEAN that suddenly 72 Mghz is bad" Mike goes on to say that 72 Mghz has served the industry well and will continue to serve us well. But try not to think of the new digital radios as RF stations but as computers.

The latency of the systems allows the mfg to update and build on a system not unlike Microsoft did on Windows. Where in the upgrades can go forward and be backward compatible at the same time. That's how these aftermarket Mfg's are able to make add
on systems for MODULE based radios and bring those systems up to 2.4.

Thinking of the radios as computers lets you know that not everyone needs nor wants a GAMERS COMPUTER, many wont ever use all
that functionality. Some will, just because they can afford the expense other won't because they have other plans for the money.

Either way when you look at this as a SYSTEM and not as a single one time piece of equipment it might make some more at ease that they can venture into 2.4 at their own pace and if they so choose back out and not be out a ton of money.

That seminar was very informative.

And a little tid bit of history I didnt know.........the fastest RC Radio in our industry is still a 1975 (72 Mghz FM) Kraft radio that was measured at .03 MS with a range of over 25,000 feet. I guess Phill Kraft really did know what he was doing.

jds

I do remembe the Kraft and ProLine systems and On a side note, The ProLine designer Jim Fosgate lives up the canyon from me - The " speed "of the those systems as noted is hardly relevant as regards the SYSTEM operation as compared to the 2.4 SYSTEM such as th e present DSM2. by Spektrum.

The new spread spectrum setups are light years ahead of the 72 stuff in overall system performance
Otherwise -why bother?
just being on a setup where frequency control is not an issue is not the only advantage
If you start with the rx size/ruggedness and parts count - you see the initial advantge
If you get into possible number of channels all with excellent resolution and matched operation of mixed channels -the ante again goes up. The list goes on-

But yes the old 72'design did work very well for what it was .







Old 05-04-2009, 07:26 AM
  #78  
outdoorhunting
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Default RE: Reason for not upgrading to 2.4

Yea.I think most guys arealways looking for bargins, I know I am.
Old 05-04-2009, 03:21 PM
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Don Lowe
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Default RE: Reason for not upgrading to 2.4

What we have now in R/C is awesome. 72 is remarkable and has given us many years of wonderful flying. Technology moves on and for one who spent a career in aerospace technology I am thrilled at the new emergenceSS. Modeling can only benefit from all of this and our pleasure in this hobby is only increased!
Old 05-05-2009, 10:59 AM
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Default RE: Reason for not upgrading to 2.4

It's been just uner 48 hours since I made my offer to you folks who want to "dump" your 72 MHz stuff. I have had one response from one who participated in this thread. I guess the rest of you guys didn't REALLY want to dump your stuff. You just wanted to sound indignant and scold all of us who don't see the need to change right now.

I am still looking for a good 72MHz computerized Futaba or Hitec system that someone can't "give" away, I don't consider $100.00 plus or minus a couple of bucks as "giving" it away. Onewasp said he couldn't get $10.00 for a good receiver and that is by far the most expensive component of a system. I don't have a list from him. It would be interesting to see what he actually has and what he really thinks this "worthless" stuff should bring.
Old 05-05-2009, 01:07 PM
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dirtybird
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Default RE: Reason for not upgrading to 2.4

I was the one that responded. Let me explain why:
I converted a 6 year old Lazy Ace to electric power. I use 9 A123 cells on a Scorpion 4025 motor. The ESC is a Chinese knockoff that I bought at an expo for $35.
The LA flies about 6 minutes and I can charge in 10.
I used an Xtreme 2.4 system in my Futaba 9C.
I flew the LA for about 50 flights and switched it back to 72 using a PCM receiver while I sent my 2.4 stuff back for update.
On the 72mhz flight the receiver went into failsafe at about 100 yards and the airplane crashed. It seems the 72 PCM receiver was wiped out by the noise generated by the KO BEC. It hadn't bothered the 2.4 system.
Old 05-05-2009, 05:04 PM
  #82  
8178
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Default RE: Reason for not upgrading to 2.4

Interesting question. When I bought my 12FG system last year I decided with the numerous 2.4 problems Futaba was having I would be better off with a 72 mhz system. I also expected Futaba would be working on new 2.4 equipment solutions to resolve the problems. They aren’t fools about what RCers will tolerate. So I bought the 72 12FG and upgraded all my systems with r5114 G3 PCM receivers. It cost more to go with the 72 system but it works extremely well with zero problems. The G3 is really high end quality stuff.

New r5114 G3 receivers are still available but on the other hand had I gone with 2.4 and upgraded my systems with r6014FS receivers I would now have a bunch of discontinued equipment. See here http://www3.towerhobbies.com/cgi-bin/wti0093p?&C=LDW I’ll eventually upgrade to 2.4 when the third or fourth generation of 2.4 stuff is ready a few years.

Greatly appreciate all the testing the early adopters are doing with the 2.4 systems so it will work well when I’m ready to upgrade.



Old 05-05-2009, 05:04 PM
  #83  
rmh
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Default RE: Reason for not upgrading to 2.4

Ididn't respond because within a month of getting my first DX7, I sold/gave away /threwaway ALL 72/53/50 stuff. That was one month after initial release.
I watched the clowns and the technically ignorant screw up their new 2,4 stuf and howl they wus robbed . "It aint completely idiot proof!!"
W T F is?
Old 05-05-2009, 07:05 PM
  #84  
dirtybird
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Default RE: Reason for not upgrading to 2.4

I can understand that if you have 72 equipment and don't want to spend a lot of money to upgrade to 2.4. 72 equipment has worked reliably for many years.
That said, 2.4 solves a couple of serious problems that bother 72mhz.
1) The possibility of being shot down by your fellow flier.
2) Problems of locally generated noise. (RFI from ignition or whatever) I worked one whole season trying to eliminate ignition noise on one of my airplanes.

What I don't understand is why anyone would buy equipment on 72,50 or whatever. Saying that there are bugs to be worked yet is just showing lack of knowledge. The 2.4 equipment has been on the market for more than two years. The chips have been used for many years in telephones, Futaba has used it in industrial equipment for many years. The basic patent for the technique was issued before WW2. In fact Tesla propose such a transmission way back about 1910. Its been around before I was born and I am 82.
Old 05-06-2009, 04:44 AM
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cap10b
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Default RE: Reason for not upgrading to 2.4

DB,
I'll second that, Greenshields mentioned in his talk that many military sources for the US Government among them Hughes Aircraft worked on 2.4 technology way back in the 50's and that the military and civilian industrial communities have pretty much spent millions of dollars in research and development. So the statement "wait for the stuff to get perfected" is kinda silly, what they really mean is wait for the QC of the brand of equipment they fly to get perfected.

jds
Old 05-06-2009, 07:31 AM
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rmh
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Default RE: Reason for not upgrading to 2.4

It will never be perfect enough for some
Charging batteries is a challange for some
Just a fact of life.
Old 05-07-2009, 12:15 AM
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Default RE: Reason for not upgrading to 2.4

I was planning on upgrading just as soon as my ATX RD8000 breaks........but the thing just keeps on going!!!
Old 05-07-2009, 11:40 AM
  #88  
Robotech
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Default RE: Reason for not upgrading to 2.4

Like many who have posted here I have not "upgraded" yet but expect I will in the near future as it becomes necessary.

One item I have to take issue with in several posts is using ignition noise as a reason to switch over. Using 2.4GHz to mask or hide a faulty ignition or a poor installation is just plain silly.
Old 05-07-2009, 12:30 PM
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dirtybird
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Default RE: Reason for not upgrading to 2.4


ORIGINAL: Robotech

Like many who have posted here I have not "upgraded" yet but expect I will in the near future as it becomes necessary.

One item I have to take issue with in several posts is using ignition noise as a reason to switch over. Using 2.4GHz to mask or hide a faulty ignition or a poor installation is just plain silly.
Shielding is much more effective for 2.4ghz as it it is for 72mhz. It does not eliminate the ignition noise problem but it makes it much more manageable. As to it being silly I guess is in the eye of the beholder.
Old 05-07-2009, 01:30 PM
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Default RE: Reason for not upgrading to 2.4


ORIGINAL: onewasp

tankertoad,

YOU are quite misinformed !!!!!

Spektrum reboots faster than you can click a stop watch.
It was a problem for a very few (those who didn't size batteries properly or who don't check their systems prior to flight, though I have only read of it. I have NEVER seen it nor have we had it occur locally. We still have generation one {firmware}Spektrums flying daily.

I fly a full load of high end digitals and have done so since they came out!
NO PROBLEM. We have a 35% Bipe flying DX7 and all digitals on 4.8Volts without problems (I happen to use A123)

Seriously, I feel that the problem is with the operator in your case____simply the way it computes
You have been at this 4 years according to your profile so some reading is in order for you.
I don't wish to seem overly harsh to someone so new to the hobby, but you simply have neither the credentials nor the experience to make a radio system judgment.

Look up XJet and go to his site on 2.4GHz and study it. He is an RF Engineer who is also an RC'r That is an unusual combination!

I will post back with the exact site so that you can get up to date. Even then you will need to keep reading as you can't define SS in a few pages. It is unique. It is the state of the art in RC.


Edit addition: Here is the link I promised: be certain to click forward at the end of each page.
http://www.rcmodelreviews.com/spreadspectrum01.shtml

Here also is a link on the Quick Connect Firmware update (note the date. This is over two months AFTER it was first available:http://www.rcuniverse.com/forum/m_70...tm.htm#7080754

Yet another site: http://www.rcgroups.com/forums/showthread.php?t=1038506


The links provided by onewasp give an excellent description of spread spectrum. Unfortunately for onewasp, the links provided also offer a couple of qualifiers that work against his barrage of insults to us "lay people:"

1) Of course if you ask enough people you're bound to find someone who has had problems with almost any brand of radio, and these new 2.4GHz systems are no better.
It's well worth remembering that we're still dealing with first-generation equipment here so there will inevitably be teething troubles and issues that need to be addressed. Indeed, both JR/Spektrum and Futaba have already faced some of these problems but things now appear to be quite stable.


2)It is true that you can't be shot down by another 2.4GHz radio control system but there is still always a chance that other forms of interference can cause you to lose control of your model. The 2.4GHz band is used by a very wide range of other electronic equipment from wireless internet to microwave ovens. There's no guarantee that one of these other devices won't interfere with your RC set.

I've been told by several people in the telecomm industry that, in some cases, microwave systems used for SCADA and process control don't use part of the 2.4 GHz bandthe systems use the ENTIRE BAND. At this point, wouldn't the symptoms be the same as if 72 MHz systems on identical frequencies were being used (erratic control or complete lockout)?

Thought I'd contribute to the discussion (and provide another target for onewasp. Bring on the ad hominem attacks).

-RamItOn









Old 05-07-2009, 03:24 PM
  #91  
rmh
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Default RE: Reason for not upgrading to 2.4

Ad hominy
or True Grits
Apparantly you don't fly 2.4 Spread Spektrum (DSM2
Notwitstanding the potential horrors-
In actual practice - they work like a charm
Of course there are those who could screw up a wet dream or bust an anvil wif a rubber mallet.
You can't fix ignorance.
Old 05-07-2009, 03:32 PM
  #92  
RamItOn
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Default RE: Reason for not upgrading to 2.4

Right, ad hominem. Don't address my arguments (or those posited by onewasp's idol, the author of the article I cited) but rather insult my intelligence. You have the zeal of a true believer. Vote for Obama lately?
Old 05-07-2009, 04:21 PM
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dirtybird
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Default RE: Reason for not upgrading to 2.4


ORIGINAL: RamItOn






2)It is true that you can't be shot down by another 2.4GHz radio control system but there is still always a chance that other forms of interference can cause you to lose control of your model. The 2.4GHz band is used by a very wide range of other electronic equipment from wireless internet to microwave ovens. There's no guarantee that one of these other devices won't interfere with your RC set.

I've been told by several people in the telecomm industry that, in some cases, microwave systems used for SCADA and process control don't use part of the 2.4 GHz bandthe systems use the ENTIRE BAND. At this point, wouldn't the symptoms be the same as if 72 MHz systems on identical frequencies were being used (erratic control or complete lockout)?

Thought I'd contribute to the discussion (and provide another target for onewasp. Bring on the ad hominem attacks).

-RamItOn
As for item 2 I live in a complex that has three wifi towers to provide service for residents that live in metal mobile homes. My 2.4 systems work just fine in the midst of all of this. I have set my system in front of the microwave ovens I have access to and they never missed a beat even when I managed to cheat the door interlock and operate the microwave with the door open.

I worked in the telecom industry but I must confess I don't know what SCADA is. As far as process control, it would seem to me that you would have a requirement for a very short range. It would be uneconomical to use high power. I certainly don't know why you would need the whole band. If you need high power for process control over a long distance I would think the prudent thing to do is go to 900mhz where you are permitted higher power. Otherwise the FCC might frown on your operation
Old 05-07-2009, 05:30 PM
  #94  
RamItOn
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Default RE: Reason for not upgrading to 2.4

Hi Dirtybird,

From what I was told, the 2.4 GHz band runs from 2.39 GHz to 2.5 GHz. Of that, the city utility in question uses from 2.4 GHz to 2.483 GHz @ 20 watts (or so, including antenna gain), and the distance between nodes isn't more than a few miles. Depending upon where our RC systems lie in that band, we could have up to 100 MHz of bandwidth on the lower side, and about 15 MHz on the upper sidemore than enough to accomodate our radios. To complicate things, however, is that competing power companies in the area also run on the same band, but possibly not on the same wedge that this utility does. Furthermore, I've been told that Ham radio operators have priority over all others on this band, and can run up the power to 500 watts...anywhere on it. The aforementioned coupled with the wireless networks, microwave ovens, wireless phones, and whatever the hell else the FCC decides to place here gives this guy pause when considering make the switch from 72 to 2.4. He's been doing this for awhile, so it gives me pause, as well.

I acknowledge that with any new technology, there is a learning curve. However, this guy's opinion and the problems that I've read about on this site (Spektrum recall, anyone?) combined with the fact that the pro-2.4 guys' arguments consist of nothing more than name-calling and statements of "that can't happen" in response to user problems that did happen give me pause. Even the guy who wrote the article that onewasp worships stated in black and white that there have been problems in the past.


SCADA = Supervising Control And Data Acquisition (I didn't know, either. Apparently, SCADA is process control).

Thanks for keeping it civil, DB.

-RamItOn
Old 05-07-2009, 08:41 PM
  #95  
dirtybird
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Default RE: Reason for not upgrading to 2.4

It was my understanding that transmissions in the 2.4ghz band are limited to 100mw.I hope that some one that knows the correct information will post it.
If hams are permitted 500w I don't think we will have too much to worry about. First 500w in that frequency is not easy to come by. I think you would have to use a klystron. Not a cheap item. Maybe a FET would do it but it surely would be a challenging design effort. Then it would be useless for over the horizon communication. About the only thing you could use it for is RADAR mapping of the moon. Maybe there are hams around that are interested in radar mapping of the moon but I don't think there are many. Even so I would expect them to use a highly directive parabolic antenna. Then the beam would be so narrow if you did cross it you would never know it.
Old 05-07-2009, 09:51 PM
  #96  
rmh
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Default RE: Reason for not upgrading to 2.4

Spektrum recall? that's a new one on me!
and I have use em from day one
updates yes but no recalls.
you really should use the product to get an understanding of it.
Old 05-07-2009, 10:48 PM
  #97  
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Default RE: Reason for not upgrading to 2.4

the DX6i was recalled...

http://www.spektrumrc.com/Articles/A...ArticleID=1901

don't get me wrong - I have a DX7 and a JR9303 w/spektrum module, but yes, there was a recall. The recall was for stick pots, not for 2.4GHz specific stuff, though.
Old 05-08-2009, 06:37 AM
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rmh
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Default RE: Reason for not upgrading to 2.4

Exactly -
The theory of 2.4 has been beaten to a fare thee well, by aspiring and sometimes retiring RF amateurs and professionals
The bottom line is that as used -for our application, it is very good .
Thadvances in mfg small electronics has further changed the scene, to give use simple ,very small rugged bits of hardware that will do ,in the space of a mouse turd, what the radios of a few years back could never hope to achieve in any practical size.
Old 05-08-2009, 11:52 AM
  #99  
RamItOn
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Default RE: Reason for not upgrading to 2.4

Dirtybird, dick Hanson,

I won't deny that 2.4 GHz works. Obviously, it does. The reason for my original post was to refute the claims made by onewasp (explicit or implicit) that a) all 72 MHz users are cavemen, and b) there are absolutely NO problems with the 2.4 GHz band. I've never had a problem with radio hits when using 72 MHz PCM, and only one instance of a hit with FM. Thus, justifying the upgrade in my case (about 15 airplanes) can't be done.

We can go 'round and 'round on technicalities here or there on RADARs, power levels allowed (500 watts is 500 watts, regardless of generation method; and when the microwave system has to be shut down for a tech to work on it, I am assuming that the transmission level is higher than .1 W), but the point is that the author of the link that onewasp posted expressed some reservation about the technology, a guy who works with radios for a living and flies RC expressed reservations about it, and there have been several threads started by seemingly competent pilots that have trouble with it. Thus, it isn't perfect. It doesn't have to be, but to pretend that there is a consensus among techs and engineers as well as users that the technology has been perfected and works without flaw is to ignore evidence.

Where's onewasp in all of this? I really was hoping to have my masculinity/technical competence/RC piloting questioned.

-Tony
Old 05-08-2009, 12:06 PM
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Dick T.
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Default RE: Reason for not upgrading to 2.4


ORIGINAL: RamItOn

Where's onewasp in all of this? I really was hoping to have my masculinity/technical competence/RC piloting questioned.

-Tony
Onewasp's head is so far up Xjet's rear he can't hear you.


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