JSF-TC

My Feedback: (2)

Read on another post that Spektrum may be developing a true frequency hopping system, similar to Futaba FASST.

Anyone know more, or is it just an unconfirmed rumor.

Paul

Radimani

Really? Does Spektrum deny DSM system? If so, they already denied that the FHSS is not ideal solution for RC. Contradiction....

slarty

Heard rumours about that some time ago, heard that it was being developed for the Japanese market initially because of their 2.4 GHz limitations. Would imagine that once its up & running, it could get rolled out elsewhere that is having a problem with allowing DSSS based systems (such as mainland europe)

Radimani

For Japanese market, JR has DSX3 for surface system of FHSS. Yes, its appearance is completely same as Spektrum radio.

slarty

That is true BUT you are limited to 10mW RF Power in Japan when using DSSS based systems. Not ideal for aircraft, but fine for car market.

Radimani

That's right. But Spektrum says DSSS is best solution for RC use. FHSS is not. Why do they provide FHSS for Japanese market even though their conclusion is DSSS. If 10mW is enough for surface application, they must stick to DSSS for Japanese surface market. Consumer will be puzzled. Does Spektrum think lightly of Japanese market?

Four Stroker

Paul Beard has been making the claim that DSM2 should be allowed under the FHSS rules of the ETSI. This would allow for 100 mW EIRP. Otherwise, DSSS can only use 10 mW which is marginal for large flying models but OK for park flyers. The great EU Harmony is due in July of this year. Spektrum may have run into difficulty getting approval based on his technical argument. The argument presented to the public is patently absurd. We of course do not know the actual argument presented to the ETSI. I have been anticipating a FHSS DSM3 this year for Japan and the EU. As Radimani says, they will have to modify their marketing. I would expect DSM2 support in the USA for years to come but can't see JR developing two separate product lines. FHSS may simply be the JR product developed before making the recent marketing deal with Spektrum.

rmh

The scuttlebutt I have heard --is that the FHSS was researched pretty thoroughly before the DSM2 was settled on as the best system for the market SPEKTRUM was after - which is : the most oft used n flown type models in the USA.
The Model Match (I would not be without it as I fly a hanger full of small foam electrics -) is an example .
I think they hit the nail square on the head
Other systems will work -of course- but NOT the same features .
I am a huge fan of the DSM2 - and now that they added the "flashing light " feature - I am even more happy with the system.
I wish I had a similar setup years ago- would have cleared up some of the "glitches and holds I got with my old equipment.

Radimani

For ETSI, if my knowledge is correct, the FHSS needs at least 15 independent frequency channels. We do not know how Mr. Paul Beard persuade ETSI official. I found that the recent DX6i has "Power Setting" function. By this function, the output power can set to some value in order to meet European rulings. Is the output power 100mW eirp on this mode?

onewasp

A slightly different perspective.

I have flown RC since the early days of single channel Simple Simul (Galloping Ghost) through reeds, the various Propo rigs and now Spektrum and Spektrum/JR.

To sum it all up I have NEVER had a more reliable (total reliability) system at any time or at any price!
If Spektrum/JR can beat DSM2 I'm all for it though my experience has been flawless which makes improvement difficult at best.

Frankly except for niche markets or overseas regulations which may have restrictive features I doubt that at this moment DSM2 is about to be superseded --------- at least for some time.

Improvements are a part of life and over time I would expect that to occur. The underlying implication that Futaba's choice of FHSS is better is simply false.
The original patent on SS dates to 1940-41 and was FHSS so that approach is neither unique nor new.
In fact with that history, if you were to begin to research a 'full range' SS RC system you would probably begin at that point.
As Dick pointed out Spektrum did but chose DSM2-------Personally I am VERY satisfied with their choice.

I have recently seen some posts on various RC forums attempting to criticize the DSM2 system for the multiple antenna Rx approach. All that tells me is that the poster either has never tried the system and/or has no idea how it works and very likely both.
The installations are super easy and you may choose your level of redundancy.
How could THAT be construed as a negative.

My personal experience of regular flying with Spektrum (16 consecutive months) leaves nothing to be desired.

Four Stroker

DSM2 was developed as an aftermarket module system. That's why the button is on the back. That's why you set the limited failsafes at bind. I was surprised to find DSM2 in the "fully integrated ground up" X9303. I was even more surprised to find it specified for the 12X.

I could have used Model Match last weekend. Spektrum has some good ideas - data logger, model match, remote receiver. The DSM2 protocol is adequate but nothing to brag about. Chip cost was probably the main driver. If you Spektrum guys keep praising DSM2, you will never get anything better. It's like being stuck with PCM 512.

onewasp

I am sorry but you have that backwards.

Spektrum announced DSM2 and said that there would be NO modules made available.

The cry for modules became intense and they then relented. Later----several months later.

This is simply a matter of record

saitofreak

"Paul Beard has been making the claim that DSM2 should be allowed under the FHSS rules of the ETSI. This would allow for 100 mW EIRP. Otherwise, DSSS can only use 10 mW which is marginal for large flying models but OK for park flyers. The great EU Harmony is due in July of this year. Spektrum may have run into difficulty getting approval based on his technical argument. The argument presented to the public is patently absurd. We of course do not know the actual argument presented to the ETSI. I have been anticipating a FHSS DSM3 this year for Japan and the EU. As Radimani says, they will have to modify their marketing. I would expect DSM2 support in the USA for years to come but can't see JR developing two separate product lines. FHSS may simply be the JR product developed before making the recent marketing deal with Spektrum."

So does all this mean that Futaba is a better choice for Europe?

onewasp

You'll have to ask the Europeans.

I believe the UK has made way for DSM2 at USA power levels but that is repeating what I have read and is NOT first hand information.

Mac Man at MacGregors would be my suggestion for a knowledgeable source on the UK allowances as well as continental Europe.

rmh

Wow - I have not seen this intreptation of the DSM2 system -
Exactly what superior system do you have in mind? Surely not anything presently on the market!! As a possible clarification of the DSM2- tx /rx etc--Look at the sales results -
Chip cost ?
chip cost is a minor part of the whole system
If the chip cost were doubled --still a minor part.

slarty

EN300-328 v1.7.1 is already "in effect", the old version retires in July this year. Although there is a "Standard" it is up to the INDIVIDUAL countries to set policy. 300-328 related to "Wideband Data Transmission Systems", nothing at all to do with RC Model Aircraft etc.

OFCOM (the UK National Authority for all things communication related) has allowed RC Modellers to use the 2.4 GHz band as long as the system complies with 300-328 ( This is not the only thing it has to comply with... 301-489, L.V.D. SAR to name an extra 3 standards). What OFCOM have done is moved the "goalposts" so that handheld RC systems can be classified as WBDTS devices.

The 10mW allowed for DSSS MUST be viewed in its fullness.... this 10mW MHz limit is the Power Spectral Density and is measured using equipment that allows for a 1MHz bandwidth both in the IF stage and Video stage (not Video as in cameras etc...) and is then subjected to a formula that takes into account Antenna gain AND Duty Cycle of the transmission. This then gives us a PSD value that is NOT TO EXCEED 10-mW MHz.

However, OFCOM are happy enough to interpret the requirements that are laid down in 300-328 for the FHSS definition, to apply to the Spektrum DSM systems. Therefore OFCOM allow Spektrum to use the full 100mW EIRP allowed for FHSS.

Other european countries could read and interpret the requirements (as per 300-328) in a different manner.


Also, any item that is already on the marketplace that was legal under 300-328 prior to a new edition is STILL LEGAL to be used. Anything NEW on the market MUST now be tested to the new edition.


phew !!

Four Stroker

If a Yugo was the only car that I had ever seen, I would consider it a marvelous invention. DSM2 Looks to me like a design to catch a converted PPM stream. The "smart guys" at my club are waiting three years before getting into 2.4. At least they will have more choices. (I'm not one of the smart guys).

I am seriously hoping that DSM2 does not reign supreme for years to come. I was hoping the 12X would be DSM3.

onewasp

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I am seriously hoping that DSM2 does not reign supreme for years to come. I was hoping the 12X would be DSM3.

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I would be interested in what it is you feel is lacking in the DSM2 protocol. As I've said I am a long time flier and I find absolutely nothing to complain about and nothing lacking for my use.

I have flown it since it's announcement and our area is now heavily DSM2.
We have roughly 10 clubs from the central area and at least another 10 clubs from the metropolitan area in addition.
Each club is roughly 100 members, save for one which prides themselves on 250+ members.[]---but still has but one field. A couple of the others have separate fields for Heli and also a separate field for non-powered.

Between us we have neither seen nor heard of a single brown out or lock out or????. This includes 40% down to some small electrics.
The only place I've ever seen this referenced is by some "poster" on one of the numerous web sites. I'm certain that someone someplace has verified one or both but??????? to any first hand knowledge.


In our case I believe every long time (expert class) flier converted last year and that includes every single HAM operator as well. I am one of those------six meters was never this good!

As always buy that which pleases you------I simply have found no fault with DSM2.
BTW the "2" refers to two transmissions on two separate frequencies as well as the more common belief that it is also the second generation of DSM.

PS The Yugo was just plain bad----

rmh

For Trablant enthusiasts - the Yugo is a step up -
Smart guys waiting 3 years ?
why not 30?
We dummies hopped on the wagon - never looked back -and lo and behold - the stuff works -and very well I might add. If I sat around waiting -I would soon be in my grave - before I got a chance to fly
Too bad you have not had to opportunity to present the superior system you apparantly have waiting in the wings .

saitofreak

Thanks for the info folks. It'll be interesting to see if JR/Spektrum migrate to a 'DSM3' type system for Europe.

Four Stroker

As onewasp said, DSM2 is for 2 frequencies. Now this I believe. So I guess FHSS would be DSM20.

onewasp

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For Trablant enthusiasts - the Yugo is a step up -

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Talk about having to s-t-r-e-t-c-h your imagination. []

I've always found it interesting that the Rusky's could be so "with it" on aircraft designs and so "way out there" on other engineering front's.[X(]

Gordito Volador

My Feedback: (1)

Ditto on that!

Regards, Bill

KB9STD

My Feedback: (1)

"As onewasp said, DSM2 is for 2 frequencies. Now this I believe."

But,OneWasp got it wrong in this case.The DX6(first 2.4 GHZ system from SPEKTRUM,and designated for "Park Flyers") used 2 frequencies.

onewasp

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But,OneWasp got it wrong in this case.The DX6(first 2.4 GHZ system from SPEKTRUM,and designated for "Park Flyers" used 2 frequencies.

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No. onewasp did NOT get it wrong.

Re-read my post and you will find that I referenced DSM2 .
DX6 was DSM NOT DSM2.
The DX7 (first of the announced DSM2 sets) will operate DSM and DSM2 but not the other way around. [X(]