[sweetpea]

Ok that explains a little more on the testing.....

I want to be clear.......

-the test involves a video transmitting device that operates on or near 2.4

-XPS works fine when the video is turned on first. It scans and moves away from that signal. (as we would expect all the 2.4 to do)

-XPS does not work when the video is turned on after XPS.

Could this be because XPS is using the first avail freq it sees (which seems logical).
Then it gets blasted with a signal on its primary freq which would happen to be the first freq in the order, and maybe there is some harmonics on the adjacent ones it tries to hop to. It can't find anything fast enough that is clear before its default timer goes into failsafe.

I would think the logic is pretty simple for the hop. At start up find the first avail signal. At signs of conflict move sequentially up in freq until you find a clear one or failsafe timer hits or something like that.

So questions I have.

-what is the failsafe timer set to or how many hops does it perform per second? and does it matter if I set the rx failsafe to the lowest setting or highest?

-How long does it sit at each freq it hops to before trying another (assuming it is trying to hop and can't find a clear freq)?

-**is the video feed so bad (strong, wide or whatever) that its blocking XPS from being able to send the hop signal successfully? (i.e. XPS talk of a slow increase of noise over a sudden burst that stays)

-How about trying a video feed at the far end of the 2.4 spectrum. This way XPS locks onto the first avail freq and the video feed is no where near....hows that effect?

-I think I've heard the same issue with Spektrum not working with video in this same manner.....since it too finds the first avail freqs. I have not heard what logic it uses for its second freq but I imagine its sequential as that is pretty easy/common to program. Also is the gap between freqs the same every time? I.E. meaning if during intial bind if the gap isn't say 25 that it must move the first freq and try again(this could explain the long bind times sometimes seen)

-FASST constant freq hopping.....what effect will it have when it hops through several of the video's taken freqs? How many used freqs before it is effected (knowing it hops fast)? Does it hop sequential as well or is it random and may continue to hop in the taken range?

**From what I've read on your results and replies on RCG from XPS this sounds like what is happening. XPS is waiting for the sudden burst to go away (as per their programming since it assumes a burst like that should be temporary). If it was a gradual increase the threshold would be met for a hop before the RX was swamped and unable to transmit the hop or met the level of the sudden burst where it decides to not switch thinking its a burst.


Ok so here is what I'm thinking at this stage: (let me know if you think I'm way off base)

So if this last part is true then one could take away that XPS decided that sudden bursts would not be that long and the risk of changing freqs on both the RX/TX getting the message and accomplishing was greater (be it time or the chance of not reconnecting) than waiting out the burst as far as loss of radio control. Thus they chose to wait it out. Going back to the fact they didn't anticipate 2 things......

1) the higher noise levels at numerous fields in the world (due to whatever is the cause). They probably had a base line that was lower than expected for worse case. These higher noise level fields are in the burst category as far as the freq hopping (just a guess)

2) customers trying to put outside R/C devices on their planes in the same freq range. Again putting the system in the burst signal strength category (this, I think all the manufacturers will be to blame on for not anticipating)

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---in my hindsight it appears that floor noise levels where beyond what they expected to worst case at most fields (probably due to the last 2 yrs of strong housing/business development all across the country and the fact they are not a Corporation with easy access to fields and pilots all across the country for absolute complete testing so they sampled, which again is pretty common practice though not always desired) and these issues have caused a few problems to the system.

1) New antenna for places like Las Vegas
2) customer induced noise floors, by using video on a freq near 2.4
3) customers demanding the satellite rx's now (which XPS stated was a feature of the telemetry in the future). [I also think this reverts back to unexpected noise levels as extra rx's would help in this situation]

I stand by everyone in that this is one fault that I can't ignore. But in the same breath I can't ignore the fault of Spektrum and the low voltage issue (which hasn't been fixed, only bandaged by us, the modelers)

Now the consumer calls foul and tells them they want it to hop no matter what, at any sign of interference. Being aware that many thought this was the case from the get go since they did not understand the complexities of how any of the systems are wired/programmed as no company releases that kind of information in advertising [Noting that XPS original advertising explanations of hopping did not go into this much detail of how it worked as it was probably too hi-tech geeky for most so they generalized which is pretty standard]


Remember...... is my thoughts only, I have no proof to back it up. To me it just seems the logical approach and I could be wrong I also don't yet any experience with FASST, and since they are currently for Futaba radios only (I don't own any of them) I most likely won't get that chance

I know Xjet doesn't have the time nor money to do all the testing we would like......but it would answer more questions to see how the other 2.4 systems react to the same test conditions.