rhklenke

My Feedback: (24)

I don't care about that. I have no interest in buying a Spektrum-based system for my own use. However, if the XG7 (soon to be followed by the XG9 I hear?) were available through an authorized US distributer, I'd be very interested in checking it out and possibly going all JR for my radios - as opposed to the split personality I have now...

Bob

malcolmm

Since I don't fly at large events with hundreds of flyers, I guess I shouldn't be concerned with the limitations of DSM2.

However, isn't there another consideration that makes frequency hopping safer? Obviously we aren't the only users of the 2.4 band. From what I have been told, if there is a lot of non RC traffic on 2.4, DSM2 isn't as safe as frequency hopping. This makes sense to me, if either of the two channels that your DSM2 radio selects becomes noisy after you turn on your transmitter/receiver, DSM2 is now down to one good channel.

I have a 9503, and since I fly away from populated areas, I'm not that concerned. However, to me, frequency hopping always seemed like a better protocol, and I'm surprised that it took Horizon so long to improve it. And since I'm planning on moving into giant scale, I really would like the additional safety of DSMX.

I also wish JR had included softward upgradability with the 9503, like the DX8 has. For a premium radio, JR has fallen far behind the state of the art. It's annoying enough that I have to pay $75, plus shipping from Canda, to upgrade my less than one year old radio. More annoying is that I have to send it in to Horizon and be unable to fly for what I would guess is at least a few weeks.

rhklenke

My Feedback: (24)

If it works for you and you're happy with it, then all is well.

That is an issue, and sometimes DSM2 will select two channels that are very close to each other , so a wide-band signal, like a Wi Fi router, or an FM video transmitter, can take out both (turning the TX off and on again usually cures it, but you have to have a spectrum analyzer to even know that it happened). As you said, in any noisy environment, picking a specific channel and not moving off of it can leave you more vulnerable to interference. I would bet, however, that this limitation has not come into play for the majority of DSM2 users, and also has no bearing on issues like brown outs, RX's becoming unbound, etc., or again, needing to have satellite RX's... Those are firmware, quality control, and receiver design issues.

Bob

karl hibbs

My Feedback: (6)

I heard HH is coming out with a on board spectrum analyzer that just plugs in to one of the antenna ports ,that way you can see if it starts up on 2 channels to close together. then you can just reboot.

impulse09

My Feedback: (3)

Bandaids...

gruntled

I can't tell you how many times I cycled my X9303 with a spectrum analyzer running trying to get it to pick two channels next to each other . . . I never once got it to happen.

rhklenke

My Feedback: (24)

We've seen it before, maybe 4 or 5 times out of 50 or 60 flights when we were checking with the spectrum analyzer...

Bob

FILE IFR

An original AR6000 RX.... your statement suggests it is a better RX, but what/which RXs in their product line would be less "champion".... and why?

gruntled

I never had any trouble with any of them when installed properly and used for their intended purpose. Obviously others have not had the same results as I have. Why? Dunno.

gruntled

Were you using a native 2.4 system or module based - just curious? Please post an unedited video cycling yours and coming up with adjacent channels one out of 12 times. I would be interested to see it. I would likewise be willing to post an unedited video of me cycling my X9303 100 times.

HighPlains

My Feedback: (1)

Has anyone on this entire thread ever studied "communications theory"?

rhklenke

My Feedback: (24)

It was on a JR 12X. It only gets checked when flying the research aircraft, not the training aircraft. It has happened enough that checking the frequencies and rebooting the TX if necessary is in the pre-flight checklist.

I have no desire or need to play dueling videos with you although if you want to see a video of some of the operations, look here:

http://www.youtube.com/watch?v=NM38A7Ojidw

Bob

bigplumbs

I doubt it

gruntled

Bob:Very cool plane. I am sorry you take it as 'dueling videos'. I have never seen anything like what you are describing and would really like to see it first hand. I am sure many others would too. A picture is worth a thousand words as they say.

rhklenke

My Feedback: (24)

Yes, both at the undergraduate and graduate level, although its not what I do now...

Bob

rhklenke

My Feedback: (24)

Well, it has happened in that project, more than once, and they were concerned enough about it that checking it for the research flights has become part of the checklist. That's about all I can tell you although if you look around, I believe that you will find others discussing this issue and there may even be some video evidence of it - I seem to recall that one of the "independent" testers out there caught during testing...

Whether you believe it or not is entirely up to you although for most users I doubt that it would cause a problem - unless it happened to occur and then some sort of wide-band noise source popped up.

Bob

HighPlains

My Feedback: (1)

Then there is some hope for rational discussion.

Craig B.

I have been reading this thread and I am amazed at the floored logic that is often used to attack/defend radio systems.

For the record I own and operate Futaba (14mz) and JR (12x and DSX9) radios in my jets. Both have their strengths and weaknesses.

I am not a radio tech, but the argument that, because JR gives you the option of using multiple satellites, they must have inferior receivers, is just pure rubbish. If it was necessary to use 2 satellites with a JR921 receiver, would JR not supply them with 2 satellites? The system will function well without the second satellite but it gives you the option of additional path diversity.

If path diversity and antenna position was not important, why do Futaba receivers need two antennae? Must be something wrong with them then hey? No, just simple physics at play requiring diversity in terms of antenna alignment/positioning. It cracks me up when all of the Futaba champions jump on here and pull JR/Spekrtum systems apart for having what their system requires too! Hilarious!

No matter how great you think your receivers are, there are simple physical limitations associated with transmission of 2.4GHz signal. Having additional receivers located in different locations within the airframe has to minimise your chances of having your signal shielded by carbon fibre, stainless thrust tubes etc or having an antenna (or only 2) orientated so they are pointing at the source signal rather than perpendicular to it. If these factors are irrelevant, why does the Futaba manual recommend that your should install your receiver antenna as far apart as possible and at right angles to each other? Furthermore, why doesn't Futaba include a module that allows the user to verify how brilliant their receivers are? Must be a big cover up/conspiracy there I guess?!!

One of the best Jet pilots in the world has had a "fly away" on a jet with the Futaba system. Guess its not as perfect as some would have us believe. I wonder if a receiver in the tail of that aircraft would have made a difference. I know if I was the owner of that jet I would have like to have had that extra chance.

Having said the above, I welcome JR adopting a frequency hopping system because philosophically, if not technically, I can appreciate the merits of that approach and I do think it would be safer than DSM2.

Would I like Futaba to have multiple satellites? YES!

Would I like to have Data logging on my Futaba receivers? YES and I would be alot more comfortable using my 14MZ if it did give me factual data on its performance rather than having to rely on the assurances of posters on internet forums.

It is a pity that Futaba is unlikely to listen to or even here my comments posted above.

And as for, "it has the option of four receivers so it must need them to perform adequately when compared to my two antenna perfect receiver system".......well I guess your two wheel drive family car would outperform my 4wd subara STI in the wet then huh? Ridiculous logic!

FILE IFR

The reason (as I understand it) why Spec/JR offers more than one satellites for their RXs (note: they didn't do this in the very beginning) is because of the 'pick 2 freq. and stay there' method of communication. If one frequency gets 'stepped on' and is rendered no good for the remainder of the flight, the second frequency is all it has to work with.... if the airplane is in a turn or in some type of unusual attitude and the only working frequency is blocked or shaded, it's lights out for the airplane.

... That's why a second or multiple satellites are offered to increase the chances of a succsesful flight. "Hoppers" don't have to worry about it too much.

If I'm mistaken about my understanding on this, please let me know where I'm wrong.

rhklenke

My Feedback: (24)

Gee Craig, thanks for pointing out that a Futaba RX has two antennas - just like all JR and Spektrum receivers, I never noticed that. Let me know when you're going to demonstrate flying your jet with a 921 RX (with its two antennas) and no satellites, that should be fun to watch.

Later...

Bob

Craig B.

Hey Bob,

What's with the sarcasm? I did not say I would fly my jet with no satellites. Perhaps you should go back and re-read my post. I fly helis with that receiver and only one satellite, even on electric helis with their noisy environment. Never a problem.

Seems like you have taken my comments about Futaba very personally. Why? Are you are rep or do you just need personal vindication? I use both Futaba and JR. I have just been pointing out floored logic used to criticise radio systems. Nothing more, nothing less. So take a chill pill mate.

I don't understand why you, and some others, find the need to sanctimoniously gun down other people and wish ill will on others, whilst distorting what was said as you did in your post. Surely you are a bigger person than that? That's the sort of attitude that makes people with valuable contributions not bother with this forum any longer. Go and read some other forums like the scale forum. You just don't find that sort of agro attitude over there.

BTW, thanks for proving me correct......

Anyway, I have better things to do than sit on RCU generating thousands of posts so I am off to do some building. Too many keyboard warriors here. Have fun.

bigplumbs

Why on earth can people not accept the simple fact that Both Futaba and JR/Spec 2.4 systems (The ones we have now) all work very well and far better than the previous 35 Mg or 72 mg. When I started in this hobby there was ony 35/72 and the forums were full of stories about interferance and lockouts. Not now despite what some would have you believe.

Lots of the high tech stuff we used to put in our jets was to overcome these problems. This stuff is now generally not necessary but people still put it all in there.

People should go with the weight of evidence in each case and not harp on about the odd few problems that there have been and will always be.

Many people on here worry about things that simply do not need to worry about. It all works well and the new stuff will hopefully be an improvement.

Oh no I said improvement............... That must surely mean that the previous stuff was all crap [&o]....... Panic Panic Panic

bigplumbs

Very well said

bobl2

My Feedback: (14)

+1.

rcjetsaok

My Feedback: (7)

Many people on here worry about things that simply do not need to worry about. It all works well and the new stuff will hopefully be an improvement.




AMEN !!!! Can I get a Hell Yea !!!!![sm=thumbup.gif]


Danno