RCModelReviews and Spektrum/Horizon

[Buzzkill]

Comment posted on youtube. They actually almost admitted dam & dsm2 systems are flawed. Almost.

Let's see what they do.

[kneedrag]

I posted the following comment to there site, mainly concerned that they are not allowing the JR based DSM2 system to be upgraded to DSMX as well.

Given your dodgy past and hidden facts could you send a test unit to be reviewed by an independent party. ie not a paid sponsor. I hear rcmodelreviews is a good place to get honest feedback on a system.
I seriously hope DSMX is an improvement on DSM2 however I feel you are being a bit vague about the reason to upgrade especially when there is a $75US attached to the upgrade and you are not allowing JR DSM2 based system to be upgraded to DSMX. Why is that?

[gruvin]

The DSMX protocol extensions appear to be driven from the main radio CPU. That being the case, and as they did in fact state in the YT video, the modules simply cannot do it, because the module socket does not have the required extra wiring to the main CPU board.

My DX7 has a bunch of additional wires (about 8 or so from memory) running from the transmitter board to the CPU board. So I guess they use those to implement frequency shifting and maybe some kind of hand shaking protocol.

Far as I can tell, DSMX is nothing more than DSM2, which *can* change frequencies, but probably doesn't do so very often. I say that because the guy in the video refers to the added feature as, "frequency agility", a term not at all commonly equated with phrases such as, "frequency hopping". The fact that DSMX and DSM2 are forward and backward compatible with each other, tends to support this theory IMO. We'll know, soon enough.

In any case, from an overall business and marketing point of view -- IE. supporting existing users, etc -- this scheme seems about the best they could do, as opposed to replacing the technology completely. In practice, though perhaps not ideal, I actually think these extensions may well be "enough". Time may tell.

[RCModelReviews]

I've seen no valid technical reason raised as to why they can't produce a module-version of DSMX and I suspect the reason they don't is purely a marketing one.

In reality, with a module-based transmitter, the radio itself is just handing off a PPM signal that can be converted into DSM2, AFHSS, FASST or whatever RF protocol is supported by the module. There's no need to refer back to the radio's CPU for any reason other than Model-Match -- which isn't supported in module-based DSM2 systems anyway.

I suspect Spektrum are keen to get users of (predominantly) older module-based JR radios to "upgrade" to a whole new system in order to get DSMX support.

Fair enough -- it's their choice and ultimately it's probably one that will earn them more money than it costs them.

Such is the world of RC me thinks.

[gruvin]

Yes -- but, marketing exercises aside, following what I said before -- I believe the DSMX extensions are merely a hack, being driven from the *main* CPU. If true, as I suspect it is, then there's nothing being done on the radio hardware itself at all. It follows logically from there, that the module version could not adopt the new extensions.

However, of course, it does not follow logically at all that they could not have implemented this new stuff in the radio hardware itself, which I guess is what you're alluding to. I guess they wanted to take advantage of the firmware upgradability of the DX 8, and well, damn the rest, basically. As you say -- marketing strategy. (But I'm only guessing. WHY can't they just TELL us ffs? *sigh*)