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Old Feb 23, 2012, 08:16 AM
Taranis Tyro...
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Originally Posted by Harry H View Post
Why can't some people just tell about what they own . Why bash something they don't have or ever intend on using
I agree - I can never understand why people become so tribal about RC kit and TXs in particular. I just go with the "best" option based on the situation. Sometimes best is cheapest to get the job done, at others it's 100% reliability, at others it's flexibility or some other performance aspect.

Over the years I have owned Hitec, JR and Multiplex TXs, and all of them had their strengths and weaknesses, so I just don’t get why some will only consider products from a single brand (and yes I know with 2.4 sometimes brand loyalty is forced on us, but there are still some flexible options – FrSky FASST receivers for example). When Spektrum came out with the first spread spectrum sets everything else suddenly seemed immediately obsolete; now even the biggest Spektrum fans would have a hard time advocating DSM2 is not one of the weaker 2.4 implementations (hence the arrival of DSMX). For most applications though I believe DSM2 remains fit for purpose and well priced. Only one thing is certain – the more choice and competition we have, the better it is for all. Horse for courses and all that!

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Originally Posted by erkq View Post
Jeez... 4 pages talking about iPods, cars, ATM's, airports... what would really be useful to me is an example... just one example of something that can be programmed into a DX8 that can't be done on the A9. I just got a brand new DX8 for $269 shipped and I'd like to feel good about it! Four pages, and it is mentioned, but no example...
I have played with a DX8 in a hobby shop and borrowed a friends Aurora for the weekend recently when I was thinking about buying one, so I have a bit of insight but not much! Here’s my 2c…

If you’ve used JR/Futaba/Spektrum before you’re more likely to warm to the DX8 quickly – the programming logic is similar to most Asian radios. That means it’s quick to set up for most standard models, but will probably (though I can’t prove this through usage) lack some flexibility for complex models. Certainly as a glider guider the mixing options still don’t tick all the boxes I need, and the concerns around DSM2 do worry me – all the BNF stuff is still DSM2 at the moment, right?

The Aurora on the other hand is a flexible as anything I’ve seen recently – it’s not a million miles from a Mpx P4000 – but that means if you’re coming from JR/Futaba/Spektrum it is going to feel alien at first despite the fact they’ve done a nice job with the model setup wizard. Assigning the switches anywhere and the inputs-to-outputs style mixing is likely to give you a better end result in terms of ultimate control, but it will take longer to get there. On the up side the Hitec 2.4 implementation seems pretty bullet-proof with only a small number of reported issues compared to DSM2 (mostly around the update procedure which does seem a little rocky), though the BODA aerials are more difficult to install cleanly and elegantly, particularly in carbon gliders. Re: your original question I find it difficult to believe there is anything a DX8 can do that an Aurora can’t from the mixing perspective, but am sure someone will now prove me wrong immediately!

Which is better? If most of your models don’t require complex mixing, fly in locations where DSM2 is proven to work without issues and want to take advantage of BNF then the DX8 is the pick. If you fly gliders or more complex power models and are prepared to invest the time in getting to know it, the Hitec is better – it has more ultimate mixing and control flexibility. If I was starting out from scratch, the Aurora would be the one I would go for. What DID I go for? A FrSky 2.4 conversion of my Mpx Evo, so I practice what I preach!

Matt
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Old Feb 23, 2012, 08:52 AM
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Originally Posted by MattyB View Post
... If most of your models donít require complex mixing, ...
What do you consider complex?
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Old Feb 23, 2012, 08:57 AM
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Originally Posted by MattyB View Post
I agree - I can never understand why people become so tribal about RC kit and TXs in particular.
I personally get uptight when a rep for a company spreads BS or slight falsehoods in an effort to make his system look superior. I think that's what gets people going more than anything else in a thread like this.

Opinion threads like this should be left to consumers of this tech only. Company reps should stay clear.

But again, that's just MY OPINION
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Old Feb 23, 2012, 09:59 AM
Taranis Tyro...
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Originally Posted by freechip View Post
What do you consider complex?
For me complex is my 4 servo wing F3F planes or my DLGs - they require lots of flight modes with differing rates/expo, multipoint mixing curves, servo slowing etc. Some of this I can do with my Evo, some I can fudge, and other bits I have to live without! From what I saw of the Aurora it would address most of these limitations, though probably not all; the DX8 seemed more limited and less flexible, though I didn't handle it for long enough to be certain. I can't talk to how either would handle other complex models like multi engine scale, large helis or jets as I don't fly those myself.

Your mileage may vary etc etc..

PS - If you want to know the radio I'd really like, on paper at least it's one of these, though at ~1000 euros it's pretty spendy. Maybe one day they will actually release it!

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Old Feb 23, 2012, 10:34 AM
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Originally Posted by freechip View Post
having paid full price which ended up being close to 500$ canadian from LHS, of course you should feel good.

Price I paid to be first I guess..
Mine was Tx only. That $500 sounds like an Rx was in there too.
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Old Feb 23, 2012, 10:40 AM
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Originally Posted by MattyB View Post
I have played with a DX8 in a hobby shop and borrowed a friends Aurora for the weekend recently when I was thinking about buying one, so I have a bit of insight but not much! Hereís my 2cÖ

If youíve used JR/Futaba/Spektrum before youíre more likely to warm to the DX8 quickly Ė the programming logic is similar to most Asian radios. That means itís quick to set up for most standard models, but will probably (though I canít prove this through usage) lack some flexibility for complex models. Certainly as a glider guider the mixing options still donít tick all the boxes I need, and the concerns around DSM2 do worry me Ė all the BNF stuff is still DSM2 at the moment, right?

The Aurora on the other hand is a flexible as anything Iíve seen recently Ė itís not a million miles from a Mpx P4000 Ė but that means if youíre coming from JR/Futaba/Spektrum it is going to feel alien at first despite the fact theyíve done a nice job with the model setup wizard. Assigning the switches anywhere and the inputs-to-outputs style mixing is likely to give you a better end result in terms of ultimate control, but it will take longer to get there. On the up side the Hitec 2.4 implementation seems pretty bullet-proof with only a small number of reported issues compared to DSM2 (mostly around the update procedure which does seem a little rocky), though the BODA aerials are more difficult to install cleanly and elegantly, particularly in carbon gliders. Re: your original question I find it difficult to believe there is anything a DX8 can do that an Aurora canít from the mixing perspective, but am sure someone will now prove me wrong immediately!

Which is better? If most of your models donít require complex mixing, fly in locations where DSM2 is proven to work without issues and want to take advantage of BNF then the DX8 is the pick. If you fly gliders or more complex power models and are prepared to invest the time in getting to know it, the Hitec is better Ė it has more ultimate mixing and control flexibility. If I was starting out from scratch, the Aurora would be the one I would go for. What DID I go for? A FrSky 2.4 conversion of my Mpx Evo, so I practice what I preach!

Matt
Thanks, Matt!

"Re: your original question I find it difficult to believe there is anything a DX8 can do that an Aurora canít from the mixing perspective"

Yes, the A9 seems more advanced. That why I asked the question.

And, yes, BNF is DSM2 and all my stuff is also 22ms 1024. But in my area no one has had trouble with it, even with Orange Rx's, which I use shamelessly!
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Old Feb 23, 2012, 10:59 AM
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Originally Posted by erkq View Post
And, yes, BNF is DSM2 and all my stuff is also 22ms 1024. But in my area no one has had trouble with it, even with Orange Rx's, which I use shamelessly!
I think you've summed up the problem for DSM2 very succinctly right there!

The mostly silent majority have had few or no issues, but those that have experienced problems tend to have had more than one (probably because they fly in locations with noisy RF where non-hopping 2.4 is more vulnerable). Those people are therefore understandably vocal on the forums, so DSM2 gets a bad name forcing Spektrum to come up with DSMX.

From an RF perspective I would still be prepared to buy a Spektrum set if I flew at the same field all the time and knew others who already did so with success. Unfortunately though as a sloper I need pretty advanced glider mixing (which until the 18 Spektrum just didn't have), and I tend to fly from a lots of different sites where I don't know anything about the RF environment. For this reason I do prefer the hopping solutions from Jeti, FrSky, Mpx, Futaba FASST etc.
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Last edited by MattyB; Feb 24, 2012 at 07:02 AM. Reason: Added Futaba to my "hoppers" list!
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Old Feb 23, 2012, 11:02 AM
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Originally Posted by MattyB View Post
For this reason I do prefer the hopping solutions from Jeti, FrSky, Mpx etc.
Is Futaba a "hopper" too with their FASST? I know you weren't specifically excluding it, seeing the "etc.".
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Old Feb 23, 2012, 11:18 AM
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United States, TN, Jamestown
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Originally Posted by erkq View Post
Is Futaba a "hopper" too with their FASST? I know you weren't specifically excluding it, seeing the "etc.".
It sure is, and always has been.
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Old Feb 24, 2012, 06:50 AM
Taranis Tyro...
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Originally Posted by erkq View Post
Is Futaba a "hopper" too with their FASST? I know you weren't specifically excluding it, seeing the "etc.".
Yep it is, I just forgot to mention it initially - addressed now.

I am far from an expert on the technicalities of the various 2.4 implementations, but luckily there are others around who are. If you're interested in the detail there is a good discussion of the of the various approaches here (though there's plenty of "my system's best" too!). One particularly inciteful post is below - his conclusion on the real world importance of the technological differences is very interesting...

Quote:
Originally Posted by Daemon View Post
Hypothetical tests setup:
Put up 80 planes all using 2.4Ghz systems broken down in these proportions.
20 of them non-hopping single channel (older XPS, older Assan, many others)
20 of them non-hopping dual channel (JR/Spektrum)
20 non-adaptive hopping (Futaba FASST, Airtronics FHSS, new XPS, maybe MPX M-LINK)
20 bi-directional adaptive hopping (Jeti Duplex, Hitec AFHSS)
For the sake of argument assume all systems have equal
sensitivity and ability to see or not see through noise, and in
these test cases none can see through the noise where they overlap
with it. And yes this is not technically accurate for a lot of reasons
which Xjet covered), but we're just comparing based on the ability to hop alone.

Test #1
Jam half the 2.4Ghz band with high power noise *after* all are in the air.

Test results:
Statistically speaking, about half of the non-hopping single channel
systems will fall out of the sky immediately because they chose a
channel inside the new jamming noise.
About one quarter of the dual channel non-hopping systems will have
picked both of their channels inside the noise and will fall out of the sky.
All of the non-adaptive hopping systems will drop about half
their packets, but since they generally send two packets per frame a
high percentage (not 100%, but high %) of frames will get
through cleanly and relatively solid control is retained.
Any true adaptive hopping systems will map out the noise, losing
a few packets in the process and then continue to hop around
in the clear area of the band with close to 100% of packets
getting through.

Test 1 Totals:
About 10 single channel, and 5 dual channel non-hopping systems
fall from the sky, and none of the hopping systems.
Advantage goes to hopping systems.

Test #2
If you took another approach and swept a narrow band jamming signal
very slowly across the whole 2.4Ghz band, it would eventually kill all single
channel non-hopping systems (all 20), most dual channel systems would be
ok as long as the narrow band noise can't span both chosen channels)
and the hopping systems, for the most part would see nothing wrong at all
losing some tiny % of their packets, while dropping an even tinier % of frames.
Advantage goes to dual channel non-hopping and all hopping.

Test #3
The only time the non-hopping system has an advantage
is when most of the band is jammed and the non-hopping
system was either switched on with the noise already
present (so it picks a channel outside of it) or it just got lucky.
If 90% of the band is jammed after the fact though,
then 10% of non-hopping systems get 100% their packets through while
100% of hopping systems only get 10% of their packets through. It's
a hypothetical advantage for non-hopping but statistically
so close to "entire band jammed" (which kills everyone)
that it lends little weight to non-hopping.

Test #4
Another way to look at it, is if you were purposely
trying to knock every plane from the sky, what would
it take. With two narrow band high powered sources of
noise I could kill every non-hopping system in the air (including the two
channel ones) with a combination sweep (like working all
combinations of a 2 number combination lock). To knock any/all
hopping systems down I'd have to saturate the majority of the 2.4Ghz
band at once which is a lot harder.

That's why many people generally believe that hopping systems are
"technically superior". In the majority of extreme real world, bench and
yes, even hypothetical tests, a hopping system gives you the highest odds
of retaining full control of your aircraft, while a non-hopping system is only
a coin flip or three away from failure. I know that'll be easy
to take out of context, but please don't. In the real world
I freely admit that the most extreme examples of interference are
very rare, but if/when they do, the odds speak for themselves.


Countering the assertion that they're
""Technically Superior" in ALL possible conditions" is a strawman
argument though, since few are claiming that. It only
needs to be better in the majority of cases, not "ALL" of them.

But you may be surprised to find that I don't really disagree with your
general conclusion. In the real world the kind of noise that could block
any SS R/C signal completely is extremely rare, although I have
seen it. I agree that most should choose their system
for other reasons. I just don't happen to agree with most
people's reasons (low cost being #1). I have run into
the more practical limitations of several systems, whether it's tied to
diversity, antenna design, packaging, durability, telemetry, and
resistance to high levels of off band noise.

I own 4 different 2.4Ghz systems and they all have real world practical
strengths and limitations that have absolutely nothing to do with cost.
I use one that is fairly unpopular around here (XPS) daily with no
problems and have for a couple years in my combat and DS foamies.
I use FASST in my FPV video plane though because it has proven itself
(through my own testing and that of many other FPV pilots) to be the most
resistant to other onboard sources of Rf noise (High powered 900Mhz and
1.3Ghz video transmitters, that swamp most other 2.4Ghz systems) and
longest practical range (I've flown it 2 miles away in same high noise FPV
environment).

But sure, if you set the bar really low, all the 2.4Ghz systems will clear it just fine.

ian
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Old Feb 24, 2012, 08:24 AM
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Nice write up -
My question- this "jamming device" which is quite selective and only turns on after a radio is linked up, seems to be hypothetical at best
never saw such a thing -or occurrance BUT a selective device could be built .
Just can't imagine it being used for any practical reason.
A jammer which simply knocks 2.4 completely seems more likely.
In actual use -since 2.4 was brought out by Spektrum - I have seen nothing -in the real world -to suggest such occurrances happen.
Can you suggest a real occurrance?
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Old Feb 24, 2012, 04:11 PM
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MattyB's Avatar
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Originally Posted by richard hanson View Post
In actual use -since 2.4 was brought out by Spektrum - I have seen nothing -in the real world -to suggest such occurrances happen.
Can you suggest a real occurrance?
No, not personally, but then the original poster does state this is a hypothetical thought experiment designed only to explain the differences in how the systems operate. Daemon is a very helpful guy I know from the slope forum though, so send him a PM if you have other questions.

At the end of the day though we are all agreeing - in 99.99% of real world situations all the dual channel systems are plenty resilient enough.
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Old Feb 24, 2012, 06:51 PM
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Originally Posted by MattyB View Post
No, not personally, but then the original poster does state this is a hypothetical thought experiment designed only to explain the differences in how the systems operate. Daemon is a very helpful guy I know from the slope forum though, so send him a PM if you have other questions.

At the end of the day though we are all agreeing - in 99.99% of real world situations all the dual channel systems are plenty resilient enough.
I was not trying to belittle the hypothosis-
I understand what he is saying but because the actual methods used in 2.4 spread spectrum,for "sending'' info- is so different than the systems which had everything on a 72 mhz channel, I think the casual observer might think that only one radio can use the same channel during the same time frame.
As you noted- in actual practice the dual channels work very well. I have never had a problem of being locked out and have flown DSM2 since it's release to the public.
Maybe living in the wild wild west, I never see a crowded /interferrence laden spectrum
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Old Feb 24, 2012, 07:25 PM
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Its all personal preference.
I have had an Eclipse7 for 12yrs and a DX7. I recently found myself wanting something new and was looking at Futaba and Hitec. I decided on the Hitec afer a month of going back and forth. The A9 i purchased had all the updated software ,so i did not need the programmer.

Receivers,up until Hitec released the Minima's they didn't offer a small receiver.That is why both Sektrum and futaba held their ground in small planes and multicopters.While the minima's are $45 ea it won't be long before they are offered in pairs of 3 like the others,or Hobbyking comes up with something like they did for the others.

The feel of the Aurora is just like my broke-in eclipse7. It's different in all aspects but the programming is very easy.It's far more capable then I intend to use it,but also allows possibilities I didn't have before.

In the end I went with what I believed I could get the best support and bang for my buck that is available,without sacrifice in performance and quality.
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Old Feb 26, 2012, 10:10 AM
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Now that you have a new DX8 you'll have to give a comparison of the two...

Quote:
Originally Posted by seefest View Post
Thats ok, thats your opinion, but the A9 screen is still a major selling point of this radio.

And I guess you probably wouldn't like the touch screens on Futabas 14MZ and 18MZ either.
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