XPS discriminates against non US customers - Page 3 - RC Groups
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Oct 16, 2007, 04:05 AM
The Revegetator
Chris F's Avatar
Yeah, simple as that! Thanks Jim.
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Oct 16, 2007, 04:45 AM
The reviewer
XJet's Avatar
Jim's been pitching the telemetry aspect because it seems very easy to do with the RF units (XBee Pro) he's using.

These nice little bits of electronics have the ability to not only handle the digital data needed to relay the stick positions to the servos but they also have several pins that offer a one-to-one virtual connection between the two modules (transmitter/receiver or receiver/transmitter).

In theory therefore, all you've got to do in order to provide telemetry is (for instance) to hook a barometric sensor up to one of the analog input pins on the receiver and the corresponding voltage will appear on the matching pin on the transmitter module.

A piece of cake.

However, as with most things, there are a few little "gotchas" involved in making use of this clever functionality and (to be honest) I think JD has done the right thing by sticking to the critical essentials of providing as good a control-link as possible (given the limitations of the RF units) rather than mucking around with add-on fluff like telemetry.

I spend six days a week working full-time on UAV control systems (including telemetry) so I know just how useless a lot of stuff like altitude, airspeed, position and most other forms of telemetry are to model-fliers. Most of this stuff would be soon turned-off or unused by anyone with half a brain.

And there's a whole lot more to telemetry than just getting data back from the plane. The biggest problem by far is exactly how you then make that information available to the pilot.

It's just not practical to have people constantly looking down at an LCD screen perched atop their transmitter because, with most models (especially if you're flying with others) it's very easy to lose track of where your model is or which model it is.

With UAVs we don't have quite the same problem because we don't actually fly the aircraft (except on takeoffs and landings *sometimes*). We can therefore make use of this telemetry through an onscreen display as part of the base-station system. It's either overlaid on the video or displayed as glass instruments on an LCD screen beside the waypoint mapping.

So, even once Jim gets his telemetry back to the transmitter, what's he going to do with it?

I suspect that if/when he delivers on telemetry we're going to see a rash of crashes caused by people forgetting to fly their models -- too focused instead on watching its airspeed, altitude or whatever via the little screen on their transmitter.

Even though I have access to telemetry information when flying a UAV, I still do take-offs and landings by the seat of my virtual-pants so to speak. There's just no time to look at any instruments when you're only half a mistake above the ground ;-)

Having said that -- there are some very useful applications for telemetry in RC equipment and I know that most of those will be available shortly, albeit not from XPS.
Oct 16, 2007, 04:57 AM
The Revegetator
Chris F's Avatar
Thanks XJet,

It is good to have your knowledge available here; it gives us a much better insight to the real XPS situation. The only real time telemetry I would be interested in would be audio. Especially when flying thermal sailplanes with the beeping instrument (can't remember what it's called) that tells you if your climbing or sinking. I probably wouldn't pay the money for it anyway. I can catch thermals without it and it's just a bit of fun as far as I'm concerned.
Oct 16, 2007, 05:06 AM
Registered User
Right now I'm chuckling to myself as people anxiously wait for the long-promised 6-channel parkflier receiver.

It ain't going to happen -- outside of the EU.

There are very good technical reasons why there are major problems in trying to get this parkflier receiver to work with the current transmitter module and I suspect Jim has discovered them already -- hence the slippage and the limitation to the EU market (where the problem won't be so apparent).
Can you elaborate? I have two of the six channel Rx's (Got in just before the NZ door slammed shut) and they are working just fine. Of course I am using them in close range parkflyers as designed.

Oct 16, 2007, 06:20 AM
Registered User
CrashingDutchman's Avatar

Are you involved in the product you are talking about or are you just a 'messenger' ?

Just curious!
Oct 16, 2007, 08:57 AM
The Revegetator
Chris F's Avatar
Originally Posted by henrykk
Hi Louie,

if you would like some interesting reading, have a look at this info that was passed on to me - makes for an ineteresting read and an insight into JD and his business practices - may make people reconsider using XPS - it did for me

The following post was from here:

EASYTIGER -> RE: XtremeLink™ - 2.4GHz for Futaba, JR, and Hitec radios (10/3/2006 3:57:55 AM)

....Someone just sent me a list of some older Jim Drew related threads in other businesses, you can read them and make of it what you will, and know that this is not the first time he has done something like this.







Henry that is amazing stuff. Jim Drew the king of HYPE has left a string of unhappy people behind him. And it's interesting that he has a history of pleading to have his own posts deleted on other forums as well as deleting ours here at RCG! It makes me wonder if XPS will be the same as his other company WAS and talk up things that never happen.

I'm very glad I didn't hand my money over to him, he reminds me very much of an old boss of mine. I just hope he does the right thing by all the people who have already bought Xtreme Link stuff. I wouldn't touch him with the proverbial 40ft pole.
Oct 16, 2007, 09:50 AM
Registered User
CrashingDutchman's Avatar
Read the 2nd comment in this page (posting from 2008/8/1):

No wonder why Jim Drew is today one of the most hated people in the Mac & PC world
Probably, he isn't the most hated person in MAC & PC world, but you don't use such strong wording without a reason
Oct 16, 2007, 10:14 AM
<- Balsa flies better ->
wolw's Avatar
They probably bought an underpriced superior product worth +$400, that Jim sold for $150 but later lost interest in and stopped supporting.

Oct 16, 2007, 10:20 AM
Registered User
CrashingDutchman's Avatar
Oh Jim, if you are reading this, please join in to comment.

Be sure that we don't delete your posts!
Oct 16, 2007, 01:19 PM
Registered User
BTW, the Corona 4ch synthesized rx are available from UH. Only 60 units of 72MHz. Too bad they are 4ch. I am only interested in 6ch or more.

Oct 16, 2007, 03:15 PM
The reviewer
XJet's Avatar
Note that the Corona units are also only single-conversion and there have been some issues with their fixed-frequency SC units and 2IM/3IM rejection. ie: watch out if you're flying in close proximity to other transmitters on the same band.

As for the technical issues with the 6-channel park-flier unit -- it boils down to the fact that the XPS modules are bi-directional with a positive-acknowledgement protocol. This means that the transmitter expects the receiver to say "yep, got that" within a short space of time or it re-sends the data.

In the regular system, the transmitter and receiver are both using relatively efficient antennas (quarter wave or dipole) so the RF link is strong.

However, if you use the lower-power version of the RF board to keep costs and weight down, and if you go to the chip-antenna (for the same reasons) then there's a very good chance that although the receiver will hear the transmitter, the reply (the "oky, got that" message) will not be picked up by the transmitter.

This means the transmitter will re-send the same data multiple times -- effectively polluting the frequencies used with unnecessary retransmissions.

This won't be such an issue where the output of the transmitter is limited to 10mW (as in many European countries) because the receiver and transmitter outputs will be pretty similar (balanced) in signal strength (ie: the receiver will stop hearing the transmitter about the same time the transmitter stops hearing the receiver).

In the USA and other countries where the XPS transmitter is set to 100mW however, it would be possible for just a few XPS systems to very quickly saturate the frequencies on which they're operating and thus create a situation where latency increases significantly.

Perhaps Jim will deny this is a problem -- in which case he's welcome to describe how this potential problem is handled, but without a viable explanation (rather than "it's a secret") I'll remain unconvinced :-)

So Heather, I'm sure your 6-channel unit works just fine -- but if you fly too far away I bet your transmitter starts using three-times the time-slots (bandwidth) than it should. not a problem if you're flying without a lot of other XPS systems around but if you were at a very busy event with lots of other XPS parkflier systems in operation then I'm not so sure.
Oct 16, 2007, 04:27 PM
And You're Not
You guys might ask Xjet how an American distributor of Saito engines was discriminating against New Zealand customers.

Or ask Hokusei why I can't buy direct from them.

Discrimination! Discrimination I tell you!

Then, back off and get a grip. Not every company in the world will deal direct to customers from every other country.
Latest blog entry: My Quad
Oct 16, 2007, 10:27 PM
Registered User
Hey Jeffery, I have no problem with that. What I have a problem with is this: Jim Drew said he contacted United Hobbies first off and got no reply from them. When I contacted UH for him and Hand from UH came on the thread to say he will get in touch with JD after he comes back from a trade show, JD started giving specious (read b.s.) reasons why he will not deal with UH now, such as UH selling other competing brands such as Spektrum and ASSAN.

Doesn't he realize that both Graupner and ME both sells other brands also, such as Spektrum and JR? What's he gonna do then? Cut these 2 off? That's why his reasons are specious and bs. Maybe he just assumes we are fools.

Oh, btw, that's when threads started disappearing. He just doesn't want us to know or doesn't give a damn about the rest of the people outside the US.

Oct 16, 2007, 10:42 PM
And You're Not
I'd rather quit the hobby (or the business) than deal with UH. I don't blame anyone for not wanting to deal with them. Maybe he was just trying to be more diplomatic than I am, I don't know. And I see no reason why he should leave threads concerning dealing with such companies in his forum, if it was up to me UH would have no representation here at all. I don't see why he owes you any explanation as to why.

And sorry if this comes off as harsh, but man, there must be 10K posts about bad service from UH here. Why anybody would even contemplate doing business with them is just beyond me.
Latest blog entry: My Quad
Oct 17, 2007, 12:25 AM
Registered User
I have order thousands of USD worth of goods from them. I have received all of them in good condition. Anything that is not working or missing was replaced quite promptly. So what is the problem? You cannot make comments such as these based on the experience of a few vociferous people who make thousands of posts on any 1 subject. I think UH has a lot of satisfied customers who never made any postings to that effect. If you go thru those complaints thread, count how many ACTUAL INDIVIDUALS there are in total making all those post. I don't thinkg there are 10K individuals or even 1K or 100 such individuals.

Anyway, I am satisfied with UH and their service and, especially, their prices.

Back to the topic: It was JD who said that he contacted them FIRST! If he cannot contact them or his email slip thru the cracks, then he should be happy that I got them to respond to him. So, what is his problem? Was he bs'ing us when JD said he tried to contact them? Anyway, I am not saying that he MUST deal thru UH. He can deal thru Tom's Internet Store for all I care, as long as Tom's Internet Store has good prices and reasonably fast service.


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