Why some XPS users are hopping mad

WILL IT OR WON'T IT HOP?

UPDATE: XPS fixes hopping issues
This article was written before XPS effectively conceded that its system was insufficiently frequency-agile to cope with real-world interference.

The XPS system now appears to be as good as any and better than some - but I'm leaving the following online to act as a piece of history.

ORIGINAL ARTICLE

When the XPS module-based 2.4GHz system was announced there was a flurry of excitement.

In fact the claims being made for this revolutionary system were almost too good to be true.

Not only was it compatible with virtually every RC transmitter on the market but it would provide all the benefits of other 2.4GHz systems and more.

Telemetry, a 5-mile range, the ability for thousands of systems to all run simultaneously without interference -- these were just some of the bold claims being made.

Well after almost 18 months some of the long-promised features still remain undelivered but in the meantime many model fliers have been using XPS without problems.

Unfortunately a growing number of formerly satisfied users have also suffered from unexplained crashes in which their models stop responding to the transmitter. XPS has pointed to a number of possible causes for these crashes and in a number of cases the problems were proven to be caused by poor installation, faulty batteries and other factors outside XPS's control.

But recently a number of people (including myself) decided to put one of XPS's more important claims to the test -- it's claimed ability to hop away from potential interference by automatically changing its frequency.

Despite the best efforts of myself and several others, there is no evidence that the XPS 2.4GHz system is able to change frequencies once it has been turned on, and that's worrying more than a few people.

For their part XPS now claim that their system will only hop under very specific circumstances - which must be even more worrying since those conditions represent a very tiny range of possible interference types.

Whereas Futaba's FASST system is constantly hopping and therefore remains almost unaffected by interference that can cover as much as half the 2.4GHz band -- and Spektrum/JR operates on two widely spaced channels so as to have some backup if one of those channels is hit by interference, XPS has no safety net.

It could be that at least a few of the mysterious crashes attributed to XPS are due to this lack of safety net. If a burst of strong noise does happen to appear on the channel XPS is using the system appears incapable of sidestepping it in the way JR/Spektrum and Futaba do.

Naturally this situation has left some XPS users hopping mad.

When they bought their systems they did so in the belief that it would automatically change frequencies to avoid potential interference and now they find that even XPS themselves can't provide testers with a scenario where this happens.

In my opinion, anyone considering the shift to 2.4GHz would be well advised to stick to either of the big-names in the industry. The claims being made for these systems are well proven and both appear to offer higher levels of resistance to interference than XPS.

The best analogy I can use is to suggest that XPS is like a fast car without seatbelts or airbags.

So long as you don't encounter some unexpected obstruction on the road, you'll never miss these safety devices but sooner or later, many people will find that belts and bags can be a lifesaver.

And so it is with 2.4GHz RC systems. If you never encounter any significant levels of interference on 2.4GHz then your XPS system will likely work as well as those from Spektrum/JR and Futaba. However, if interference does appear, the big-name systems have an inherent ability to dodge what XPS can't.

Your choice.

Feedback