RC Model Reviews

Review: Spektrum DSMX

There it is -- Spektrum have finally caught up and possibly passed the rest of the 2.4GHz manufacturers when it comes to delivering a powerful, resilient link between pilot and plane.

In theory, DSMX is better than the rest but in practice the difference seems pretty academic since all of the FHSS systems show remarkable resilience to interference.

I love my DX8. All my Futaba club members will even say it is the easiest to program. Just beware of purchasing used DX8's. I purchased mine new in January. It was not in the recall list that Bruce mentioned back in June. Unfortunately I lost the lock on an AR6200 RX and thus lost a plane in a crash. Spektrum added my DX8 to the recall list the following week. If you purchase a used DX8 make sure it does not need the firmware upgrade. Also, always make sure that it has the software upgrades as well (user install-able).

Good review Bruce, thanks (and boo hiss to $pektrum for their ad hominem attacks on you).

Though perhaps you could reiterate what the various acronyms mean once, at the start, for forgetful old farts like me (the guy who recently wrote DUI kit, when I meant DIY).

I mean, I've forgotten what DSSS means altogether (although it sounds ominously like something to do with my pension being cancelled) and FHSS could be Futaba-speak for Fart Hard Super Shite for all I know.

Frequency Hopping Spread Spectrum
Direct Sequence Spread Spectrum

I'm pretty sure I know what each does, but I had to look up the anacronyms as well.

FH makes rows of spikes (hopping) and DS makes a fat spike (spread).

Excellent review, the DSMX radios are undoubtably better than DSM2 however after two years of flying with JR DSX9 Tx and multiple JR and Spectrum DSM 2 rxs I have had no issues whatever. The only problem I have had was due to me letting the rx battery run flat.

Are there any tech reviews of DSM-J? I think that was the system marketed in Europe.

Just professional curiosity.

Found it, duh. Is it compatible with DSMX?

http://www.rcmodelreviews.com/dsmjreview.shtml

I found DMSS with telemetry (Dual Modulation Spread Spectrum) as well, is this not FIVE somewhat incompatible systems?

http://www.youtube.com/watch?v=0JzVZO2qH6E

I used to like JR. This is too much.

Sid Sideslip wrote:Good review Bruce, thanks (and boo hiss to $pektrum for their ad hominem attacks on you).

Ugly Americans.

The failure mode for FHSS (DSMX) systems is much better than that of non-aglie DSSS (DSM2) systems.

FHSS will keep sneaking packets through (ie: allow you to maintain control, albeit with growing latency) as the band gets increasingly filled with noise. In my tests, even if there is just 10% of the band unaffected by noise, FHSS systems will still deliver useful control. Non-agile DSSS however, will tend to fail as soon as the portion it is using is overwhelmed, even if there is a completely silent portion of the band right next door.

why has no manufacturer tried simply upping the chiprate to the point where it covers the entire 2.4ghz bandwidth btw? is there some maximum channel bandwidth limitation that im not aware of?