Review: WFly 2.4GHz module and receivers

PAGE 2: GETTING TECHNICAL

Dated: 9 March 2010

As I mentioned on the previous page, the WFly system uses four channels on the 2.4GHz band to provide a reliable link between transmitter and receiver.

One note of concern is that the system is not adaptive. When it's turned on, it allocates operating channels without any consideration of noise that might already be on the band. In testing, it repeatedly placed two of its channels on part of the band that I deliberately filled with a very high level of noise. The system still worked but if it had placed all channels outside the noisy portion of the band, it would have had twice as much tollerance of additional interference.

I also noticed that when initially turned on, the system would allocate the two lowest channels in the band very close together -- overlapping in fact.

Cycling the transmitter power would then see the channels re-allocated with far more sensible spacing. I have no idea why this happens, perhaps WFly can enlighten us.

Receiver Performance

Both the 6-channel and 9-channel receivers reviewed had equal sensitivity although, at long range the diversity offered by the 9-channel unit may pay some dividends.

During testing however, range was never an issue with the WFly system and, like most of the 2.4GHz systems tested, it offers more than enough range for even the most extreme RC flying.

One area where these receivers excel is their reboot times. If the power is removed and restored, they come back to life almost instantly -- in fact the boot time was almost too short to measure.

When you combine this "instant reboot" capability with the good (but not the best) low-voltage performance, it makes the WFly receivers a good little package. When the supply voltage was slowly decreased, the receivers continued working right down to 3.1V. This is very good but other systems have proven to be better.

As mentioned above, in terms of handling interference, the 4-channel operation makes for a robust radio link between transmitter and receiver and during my testing I found it very difficult (almost impossible) to knock the WFly system out of action unless using ridiculously artificial test scenarios.

The Transmitter Module

Unlike most of the other 2.4GHz module/receiver combos on the market, the WFly transmitter module only comes in Futaba/Hitec-compatible form.

The module is a nice fit in both a Futaba 9C and Hitec radios but the positioning of the antenna makes use in the Hitec radios rather problematic. Although I really prefer modules that have the antenna mounted on a small platform or bulge at the back, in this case it means that if the module is installed into a Hitec radio, the antenna points directly down and must be rotated to put the radio down then rotated back for use.

WFly could solve this issue by simply providing another hole on the opposite side of the plastic. This would allow them (or users) to simply unscrew the antenna socket and reposition it to suit their radio.

Aside from the previously noted unevenness of the power-output at opposite ends of the band, the transmitter module appears to work well and is nicely constructed.

However, I do note that WFly specify an operating voltage range of from 9V to 12V. The lower figure of 9V seems a little high, especially in an era when just about all the electronics inside a modern radio is only using 2.5-5V.

An interesting observation is that the failsafe settings are stored by pressing the bind button on the transmitter module -- rather than the more common system which involves pressing the bind button on the receiver. This is a good -- it means you can reset your failsafe settings without having to delve into the bowels of your model.

Another thing that impressed me about the WFly was the obviously high resolution the system offers. Combined with the WFly 9-channel radio I think this would be a superb setup for precision flying offering smoothness and accuracy unmatched in the industry (if the WFly 9-channel radio spec's are to believed).

Summary

It's hard to fault the WFly system which, apart from the difficulty in using it with Hitec radios and the lack of a JR-type module, is well designed and made.

One excellent example of WFly's innovativeness is that the failsafe settings are set from the transmitter module and not from the receiver. This means you don't have to remove a model's wing or dig deep into its bowels to alter your failsafe settings, as is the case with most other 2.4GHz module-based systems with failsafe.

However, the WFLy doesn't have a power-down range-test mode like "brand name" products and the FrSky so range-checking will be problematic. Perhaps it's about time someone made a small "dummy" antenna that effectively absorbs the transmitter's power but only radiates a very weak signal. This would allow all systems to be range-checked over a sensible distance.

Originally WFly looked as if it was going to sell through a network of resellers but more recently they seem to have started selling direct via eBay. This is a double-edged sword.

On the positive side it has brought the prices down from $145 for a module/receiver combo to just $120 for a module and two 9-channel receivers. There's just no way to justify the former price but the new price is far more attractive.

The WFly doesn't seem to adapt to the dynamic RF environment that is often found on the 2.4GHz band and that's a point against it. However, it does use enough of the band that it does provide a robust link between transmitter and receiver.

Will it sell?

Well, if you've got one of those hi-resolution WFly 9-channel radios then this is the module/receiver you really need to make full use of that 12-bit (4096 step) resolution.

However, if you've got a Hitec or Futaba radio, odds are that it'll be a hard sell for WFly. The WFly system doesn't have the telemetry or the support network that Hitec offers with its Optima AFHSS system and it doesn't have the cache' that Futaba's FASST carries with it.

Personally, I'd like to see how well the WFly 9-channel radio works with this module/receiver combo. I have a feeling that the very high resolution (four times that of the Hitec Aurora 9 and twice that of Futaba and JR offerings) would be an eye-opener to anyone flying precision aerobatics or other demanding disciplines.

Pro's:

• Well made
• Good interference rejection (uses 4-parts of the band)
• Lightweight receivers with top and end-pin
• Good low-voltage performance
• Truly excellent reboot times
• Easy to bind and fast link-up
• Extremely smooth servo movement and great resolution
• Very effective, easy to set failsafe
• FCC & CE Certified

Cons:

• Transmitter module awkward to use in Hitec radios
• sleeved dipoles on receivers may not suit some installations
• Doesn't check for noise on the band before allocating its channels

Page 1 of this review

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