Turner2

So, Spektrum receivers shouldn't need this extra stuff but you only fly JR and orange with this extra stuff. Brilliant.

lawrence b

Aerocal,
I will give it a try and see if I can explain the basic differences between the two systems.

The Spektrum early 2.4 systems only used 2 different frequency's that your signal hopped between during your transmissions, every time you turn on your Spektrum TX it will select a different set of the 2 frequency's within the 2.4 band. The problem is that sometimes the 2 frequencys that come up are right next to each other so a external interference signal could "shoot down" both of your signals. Spektrum fixed this with their newer systems by using three sets of the old dual hopping circuits, so now with Spektrum you have 6 different frequency's that will be different each time you turn on your TX. By doing this it makes the possibility of interference much less because of the random frequencies being spread further apart and not popping up right next to each other. The 6 frequencies that do pop up at random every time you turn on your TX do not change during the entire flight, and this is the huge difference between Spektrum & Futaba.
Futaba's Fasst system actually uses a "smart" hopping frequency system which will look ahead prior to hopping to the next frequency. If the system sees interference on the frequency that is going to hop to it will go to the next frequency and so on. I am told that Futaba developed this special chip just for their systems so the Futaba signal will actually run the entire 2.4 spread during your flight hopping to only the clear frequencies to transmit your signal.
This can be seen on an oscilloscope, Spektrum will only send a signal on 6 fixed frequencies, and the Futaba will scan the entire 2.4 range the entire time. As I said each time you turn on your Spekteum the 6 frequencies are different but the cool thing about the Futaba system is that it runs the entire 2.4 range all the time!

I also know of a group in the military who run commercially available R/C systems and every year this group will test all the systems to see how well the signals stand up to a bombardment of outside interference. These guys will bench check all the brands and Futaba always comes out on top because of their "hopping" system being able to dodge the outside interference.

Hopefully this makes some sense to you,

sro2004

The gentleman approaches Spectrum wanting a DX18 as "compensation" for his many crashed airplanes. Spectrum tells him no. The gentleman kicks off his PR blitz to smear the company and exact his revenge.

Now, conveniently, the gentleman takes exception to a few critical posts and proclaims he is through, thinking this a graceful exit from his campaign.

Sir, please follow through on your promise to produce conclusive evidence of the inherent issue with Spectrum receivers. Otherwise, your credibility is nil and you are exposed.

Turner2

I'm not a radio technology expert but even I can see that your descriptions of DSM2 and DSMX are dead wrong in some areas and backwards in others. I recommend you do a little research before trying to school us on this stuff.

lawrence b

Please then, set us all straight. I await your explanation of the differences between the two systems.

I am only going on what my engineering friends (who are experts in their fields) have told and showed me, I am by no means a radio expert!

Larry B

AndyKunz

Larry,

When you talk about 2 frequencies you're talking about DSM2. The information that the 2 frequencies were adjacent is incorrect, and is based on a video that Bruce did using inadequate equipment. I forget the exact number, but IIRC the minimum spacing was 8MHz unless the band was especially crowded.

With DSMX that's all gone. It uses 23 frequencies spread pretty much evenly across the 80 MHz band. In addition, because our transmissions are very short bursts, we do not need to listen before talking like Futaba and others need to do to be compliant. That means that you don't have to worry about latency variations - our transmissions ALWAYS come out on time.

If somebody is saying we're only using 6 frequencies they are way, way wrong. We use 23. They're spread across the entire 80 MHz available. Please check with us for information like this. You can PM me if you like.

Andy

lawrence b

Andy,
I will relay that info to my Albuquerque friends. I am considering changing over to Futaba because of what I have been told, I feel a whole lot better about my Spektrum stuff after hearing what you have told me!
I really like my Spektrum DX8 and have had NO problems with it so I kinda hate to change over, and I really don't want to learn how to program a Futaba!

Like AeroCal said, we never stop learning! Thank you Andy!
Larry B

AndyKunz

DX8's operating version 2.0 or higher code are DSMX. We shipped them with the hardware capability from the very start, and made it available as an AirWare upgrade in 2010.

When you bind to a DSMX receiver you should see it tell you that it was a DSMX bind. The Frame Rate screen would allow you to limit it to DSM2 if you wanted for some reason, but nowadays most people are using DSMX receivers.

Andy

BC98

I had a the same problem, had flown once and every thing was fine. Next flight , took off and about 100 feet lost control would get it back and it would happen again, this went on for what seemed like a week. It ended up in the top of a tree.
I use two LiFe 2s batt on the rx, check them before each flight and also do a range check.

BC98

kurtataltos

As a newbie to THIS board... reading this particular forum thread is entertaining and somewhat amusing. I used to fly Futaba's in the 80's... great radios, now flying Spektrum, doing just fine ! But this thread... you have got to be kidding....

Apparently the prime OP has "the answer" for supposed issues with Spektrum and has been touting "the answer" for some time, willing to post a video to prove how bad Spektrum is, blah, blah, blah. But... no specifics. Odd. Threatening a class action suit (ohhhhhh...) Blah, blah, blah. Still no specifics. Having been pressed for SOMETHING of substance from the OP, the focus point appears to be brown-outs caused by the Spektrum receiver not being able to handle current required by large servos ( still in theory mode, no specifics). Or is it batteries ? Or charging ? Or fortuitous distortion and swamp gas ? OP lost "$40,000" due to these failures supposedly caused by Spektrum. Oooooookay.... yet you still chose to continue to fly Spektrum. More "odd". How hard would it be to measure the current on a fully loaded receiver, maxed out, and see whether it goes brown in spec or out of spec? Even exceed the spec (current draw) in the testing and see what happens.... Not hard at all... Measuring current is not considered a technical achievement in modern science. Really. But rather than actually DO something to prove a perception (word carefully chosen) its far more fun (apparently) to blast away on a forum. Funny reading. I think some folks need to check their med schedules and perhaps lay off the recreational drugs. If you have f-a-c-t-s, great !!! I look forward to reading them and thoroughly appreciate your efforts. Innuendo, sour grapes, whining, guessing, subjective commentary, bombastic rhetoric and capital letter flames... sorry, your credibility is nil, zero, zilch, nada, zip. I will gleefully await demonstrated f-a-c-t-s. Until that time, I will continue to fly my Spektrum without worry. Enjoy in good health.

lawrence b

Andy,
Another quick question for you, with the Spektrum system does the TX use the same 23 frequencies the entire flight or does the system hop to different frequencies during the same flight?

I am also guessing that every time I turn on the TX it picks a different set of 23 frequencies to transmit on?

And would I be correct in saying that the Spektrum fires it's transmission in short bursts to the RX instead of a continuous signal like Futaba?

Thanks in advance for any info, and I must apologize for being incorrect in my explanation! I am still learning

Larry B

TOPGUN WINNER

My Feedback: (27)

SOE2004.... ANOTHER BULL S____ POST FOR WHATEVER REASON. WHAT HAPPENED WAS THIS:
I HAD RADIO FAILURE ON A DOZEN AIRCRAFT IN FRONT OF HUNDREDS OF WITNESSES. I THOUGHT SOMEONE LIKE YOU APPEAR TO BE MIGHT HAVE JAMMED OVER 30 AIRCRAFT AT OUR CLUB.

I SENT MY RADIO Tx AND MAYBE 6 RECEIVERS TO MY TRUSTED COMPANY SPEKTRUM..(.I TALKED AT LEAST 100 PEOPLE INTO BUYING SPEKTRUM Tx IN THE LAST 4 YEARS._

THEY HAD MY RADIO FOR 3 WEEKS AND SAID THEY COULD NOT FIND ANYTHING WRONG WITH THE Tx....TODAY AFTER MY TESTING I KNOW IT IS TRUE. I LOVE SPEKTRUM Tx.

THEY DID SEND ME SOME NEW Rx AND i THANKED THEM VERY MUCH...I did ask them to replace my Tx with a different one ( They did not know what was wrong with it but it did fail and I had the videos .) I asked for a DX-18 and they said how about a new DX-7 and I said "great...I love that Tx. All was good...I thought.

Put all new stuff in my original test aircraft and guess what...Same old thing...

Then it dawned on me...They know they have a problem and are covering it up...They are not doing the right tests...It would be very simple to do.

I called them to tell them I would do the tests for them...They would not take my call.

I went through three weeks of developing my methodology and started testing right from scratch. All the Spektrum Rx woud brown out if you used digital servos (6 servos- all Spektrum) o.k.

Sounds like the can't handle the Amps it takes and causes a brown out...Now comes test Aircraft #2 a 500" yak-55 with a new os-55AX six HI-TEK - 645 MG Servos (standard at the clubs i fly at)

I tested the radio system and it worked perfect on the ground (I neglected to put pressure on the control surfaces to simulate air pressure when flying) We went to the field and flew some high speed racing planes just for fun and then i told my friends...lets try the yak-55.

Did the range check as I always do with first or anytime i bind a Rx. All was well...Snap roll on the ground no problem.

Half throttle take of into the wind and all is well. Gave it full power and pulled up on 45 and it went nuts...No control of any kind...cut the throttle and it kept going crazy untill it hit the ground...battery checked 6.4 volts.

Scrapped the plane and when I was leaving someone said use your orange Rx you never had a problem with them.

I was pissed off...another airplane bites the dust thanks to Spektrum.

I got out my first test aircraft ...The gas Su-26 . I left everything exactly the same...never even charged the battery that had been sitting...I put in a cheep Hobby King Rx and got out my camera. This airplane failed every time with the DX-7 & DX-8...a snap caused instant brown out. Still using the Spectrum Digital Servos exactly as before.

I absolutely could get that $17.00 Orange Rx to fail no matter what i did....I even held the control surfaces and it kept on going. That was the first time I had ever tested an Orange product because they had never gave me a reason to.

I tried to get through to someone in top management. I told the phone operator that i had found out what their problem was and it was not the Transmitter. She tried to connect me with their Corporate Attorney...What was she going to do?

Then I asked to speak with Dan Smith Supervisor of the Support Team...A very nice Guy that goes out of the way to help a customer.

He told my to tell him what the problem was and how to fix it. I said I still wanted a cheap DX-18 and i would send him everything.( the yak was worth $700 more than double what the radio cost.)

He said I could not talk to anyone at corporate period. I asked him to pass on my message. If Spectrum was just going to cover it up again I would post it on u-tube...He thought i should do that. So I said fine and hung up.

Some Club Members stopped by and said I should put it on RCU and that we would get a lot of support to fix the problem...Well, a few Spectrum people started to harass me because I I new how to fix it. I told them I would post the Movies and the explanations for a simple fix on Monday.

I wanted the input from my friends and fellow pilots. to substantiate what we already knew. Then I would post the movies...I even asked for help on downloading because I never did anything like this before. Right now, I no longer feel the need to do anything more. I told you the problem. I told you how to test it and get the same results. I told you a simple fix...YOU CAN FORGET THE MOVIES AND POPCORN. A HALF DOZEN "BLACK HATS" RUINED IT FOR ME AND EVERYONE ELSE. GOODBYE TO MY FRIENDS...TO THE BLACK HATS WELL YOU KNOW WHO YOU ARE.

IF YOU EVER SEE AN OLD COWBOY MOVIE LIKE THE LONE RANGER: THE GOOD GUYS WORE WHITE HATS AND THE BAD GUYS WORE THE BLACK HATS...IT WAS FOR THE LITTLE KIDS TO UNDERSTAND.

Turner2

DSM2 selected two clear frequencies on start up and stayed on them throughout the session. It did not hop during the session.

DSMX is a hopping system. Before you edited your post you said otherwise. I think you need to do some more editing.

Turner2

Dude, you should read your own posts while looking in a mirror. You more than anyone here can benefit from your advice above.

AndyKunz

The 23 frequencies are fixed for the entire flight. Because of the full spectrum usage, there is no need to dynamically change frequencies.

Futaba outputs in bursts too - it has to, that's a necessity for compliance! Futaba is on for more than 10% of the time, so it has to listen before it's allowed to talk. We use less bandwidth, so we can talk anytime we want.

Most of us here are still learning. I'm certainly in that category too!

Andy

skyarrow1

Ok... first off, while I have been flying for years, I still consider myself a beginner. I just don't get a lot of time to fly. I fly Spectrum with a DX-18 first generation. In the little time I have flown with it, I have had no issue and I fly giant scale. While a lot of what being said about Spectrum concerns me since some of my models are not cheep.

One question I would have would be, if someone has lost thousands of dollars worth of planes, why would you not have changed to a different radio earlier?
Have there never been brownouts with Futaba? If the answer is no, why does not everyone fly Futaba then?

We have people flying at our field with planes that are worth 5x what mine are worth and they fly Spectrum and due to their recommendations is why I currently do.

Not trying to be a smarta@# here, just curious and trying to learn.

Thanks,
Mike

lawrence b

Turner2,
According to Andy the DSMX is not a frequency hopping system, it stays on the randomly chosen 23 frequencies that are selected when you turn on your TX. That's if I'm understanding his explanation correctly.
Or does the signal "hop" among the selected 23 frequencies? In that case you are correct!
Larry B

HoundDog

My Feedback: (49)

I don't know why there are so many radio induced crashes with Spectrums other that there are a lot of them at any given field. I thought that when Spectrum finally went to a hopping system it would cure the problem going from DSM2 to DSNX. Maybe many are still using the old DSM2 receivers with the newer Transmitters. Never did understand why Spectrums radio systems would be come UNBOUND for no apparent reason. I've never had a Radio caused crash except when I tried to use Futaba CAPS 9 with the 1st & 2nd software version of the Xtreme Power Systems Modules. I've used Airtronics Futaba, HiTec RCD Aurora 9 Transmitter. Never had a radio failure of any kind not even a brown out because the Xmitter allows me to set up a minimum Receiver Voltage thru the built in Telemetry system.

I have noticed that very fuew of the JET and BIG BIRD or IMAC flyers don't seem to have all the problems that the less experienced pilots seem to have.

So in conclusion I guess the old adage of "U get what U pay for" still stands.

AndyKunz

Yes.

It transmits on channel X, then 4ms later again. 11ms after the first it transmits on channel Y, then 4ms later again. 11ms later it transmits on channel Z, ...

X, Y, and Z (and 20 other letters ) are arranged in a pseudo-random sequence which causes it to hop across the entire spectrum, hitting every one of the 23 frequencies about twice per second.

That's pretty much the same way they all work.

Andy

AndyKunz

My only radio-related crash was due to a bug in my software in non-production code.

Andy

dirtybird

My Feedback: (5)

IF YOU UNDERSTAND COMPUTER PROGRAMMING I HIGHLY RECOMMEND THE "TARANUS PLUS" Tx THEY ARE THE FUTURE OF RC. ONLY $200 WITH A BEAUTIFUL CASE....FULL TELEMETRY INCLUDED AND DOES EVERYTHING THE FUTABA DOES...JUST TAKES TIME TO FIGURE OUT THE PROGRAMMING...CHECK OUT U-TUBE ..IT PRETTY MUCH DOMINATES THE DRONE & QUAD PILOTS.
A 16 CHANNEL RECEIVER WITH TELEMETRY IS ONLY $32.00...IT HAS S-BUS..I FLY MY BIG QUAD WITH ONLY ONE PLUG IN....I HAVE GPS, AUTO LAND AND AUTOMATIC HOME THAT LANDS WITHIN TWO FEET OF TAKE OFF.

There is one thing I agree with.
I have had Taranis since 2013. I still crash but with the telemetry log I always know what went wrong. Its never been the radio.
I don't think it is hard to program if you stay away from it exotic features but they are there if you want to play with them. It sure is a lot easier to program then my multiplex.

AndyKunz

Something good has come out of this thread. I had never heard about plaques on the moon, so over lunch today I did a little googling and found two related items.

1) Anybody can have their name on the moon: http://www.nasa.gov/home/hqnews/2008..._The_Moon.html

2) The lunar landers actually had plaques on them: https://en.wikipedia.org/wiki/Lunar_plaque

Andy
PS - My name is in a book in Heaven.

TOPGUN WINNER

My Feedback: (27)

MIKE...GOOD INPUT AND WELL STATED.

I HAVE EXPLAINED IT IN SEVERAL THREADS. GO BACK AND RE-READ THE ONES ABOUT THE TEST.. IF YOU FLY STICKS AND SMALL PLANES WITH 4 OR 5 STANDARD SERVOS YOU WILL LOVE YOUR SPEKTRUM AND NEVER HAVE A PROBLEM.

THE Tx IS GREAT IT IS ONLY THE Rx THAT IS BAD...IF TOU USE HEAVY DUTY SERVOS, DIGITAL SERVOS OR FLY 3-D WITH SIX SERVOS YOU WILL HAVE A PROBLEM. RUN THE TEST AT HOME. IF YOU REALLY WANT TO LEARN, I WILL SEND YOU THE VIDIOS OF OUR TESTS...SELF EXPLAINING. VERY SIMPLE NO SPECIAL ELECTRONIC EQUIPMENT.

I EXPLAINED WHY IN A RECENT THREAD...WE DID NOT THINK THE PROBLEM WAS SPEKTRUM...LATEST AND GREATEST TECHNOLOGY...MOST PEOPLE FLYING STICKS WITH .46 TT ENGINES.

IT NEVER INTERED OUR MINDS THAT THE Rx WOULD NOT SUPPORT THE SERVOS.

sro2004

I guess that's part of the issue, Topgun Winner. You continue to mention testing and results, yet, there's nothing you've shared which indicates any valid testing. I'm no electrical engineer, but I assume to test your hypothesis, you would need to set up a test rig consisting of in-plane radio equipment and a method to increase servo load in a controllable, measureable manner. You could then drop in various Spektrum receivers and load up the draw to determine the amperage where the receiver looses power. Then, to make the test results mean anything, you'd need to test a number of different brands in the same way. Anything short of this is simply subjective hearsay.

rgburrill

Really? Not disclosd to the public? Where have you been the last many years that this problem has been disclosed?