Whats the difference between FHSS and FASST?

[kc]

The latest Ripmax new items catalogue contains a number of new Futaba 2.4Ghz receivers for their FHSS system which is not compatible with their FASST systems. But what’s the technical difference and why?

Is it better? Or is it just different so we cannot use these cheaper receivers with existing FASST transmitters?

Is FASST better?

 

[kc]

I have just noticed that the Sanwa & Saturn systems have the same initials ' FHSS ' does this mean they are compatible ? Maybe just badge engineering?

Some Sanwa were also said to be FHSS-2 or FHSS-3 . Whats the compatibility with these?

[birdy]

I think that they are probably just as good, but FHSS seems to be on the lower end offerings - although the new 6 channel tx has better specs than mine . The other thing is this "s-bus" thing - do they expect everyone to buy a load of fancy servos or decoders?

[Biggles' Elder Brother - Moderator]

FHSS - Frequency Hopping Spread Spectrum - is a generic term for the technology - like calling an engine "IC" they're all IC but the bits don't necessarly fit one another! So it is with FHSS - its the general term but the detailed implementation will be different so different FHSS systems will not speak to each other.

 

The thing about spread spectrum technology is that its not really one system - its really just a "concept" or the shell/outline of the idea. There are in practice lots of different ways you can actually implement it. In fact there are probably an infinity of different ways in terms of the details like like what error checking systems you build in, what ID systems etc. etc. Spread spectrum is in reality an algorithm - how you actually code, or program, that algorithm to realise your particular system, and still stay within the basic outline, is up to you. One way of thinking about it is that Spread Spectrum is a computer program - not hardware - so you can design it - within a set of rules - exactly how you want.

 

For Futaba FHSS is the name they give their most basic implimentation of the shell. Limited "bells and whistles" - just a straight forward implementation of how to send control signals from a transmitter to a receiver - full stop. Its only available on their basic (I think 4 channel only - not sure about that) systems.

 

FASST (Futaba Advanced Spread Spectrum Technology) - is a different beast. Yes it does the command transmitting thing, just like FHSS, but it has lots of additional information in its specific coding. Information used to achieve lower error rates, better error detection, faster operation, more sophisticated techniques for deciding on channel swaps and so on. In addition it has lots of software "hooks" for future expansion - for example see the new S-bus system Futaba are pushing. FASST will be "future proof" for some time and more new developments will come.

 

All this increased sophistication and complexity needs more complex receivers and transmission elctronics - hence why FASST systems are more expensive.

 

BEB

 

PS I don't work for Futaba - but I do use it and I read their website! Sad isn't it!

Edited By Biggles' Elder Brother - Moderator on 24/03/2011 20:55:16

[kc]

Well some of the cheap systems are FHSS but 2 of the Sanwa FHSS-2 & 3 models were in the 400 to 500 pound range last year.

But why two different Futaba systems with new models that are incompatible?

Some of the new models are 6 channel ( look at the catalogue which comes with your BMFA News this week. ) and some receivers are S-FHSS whatever that is.

 

This seems like an own goal to me.....Futaba would do better to tie the newcomers in to the FASST system rather than another different system........unless there is some technical advantage.

Edited By kc on 24/03/2011 20:48:06

[Biggles' Elder Brother - Moderator]

Well, first of all its just a Futaba thing that classes FHSS as "the basic system" there is no rule about that. I mean a Zenoah 50cc and a Rolls-Royce 6-litre V12 are both "IC" - but the similarly ends there! Futaba just decided to name their basic system after the generic technology name. It doesn't mean other manufacturers take the same view!

 

Why two systems? Well only Futaba know the answer to that. But I'm guessing the following:

 

Spread Spectrum is a computer program - to some extent what's possible is limited only by your imagination and the speed of the digital electronics available.

 

When Futaba set out to make a 2.4 system they designed it based on their already existing "professional" 2.4 systems as sold to the military and the like. Leading edge was the motto. "Let's design it with an eye to the future - maybe there are things we could write the software for now but we can't actually do now, because the electronics isn't fast enough - or "large" enough in terms of memory etc. But it will be in 5 years. So let's design an "expandable" system. Let's put in all the "spaces" for these later add ons etc."

 

This is fine - but.....its not cheap as an approach. And maybe not all modellers want all these extra features. S-bus means you can run, I don't know, 30 servos off your Rx without a "power box" and all those servos will beindividually addressable and so individually travel adjusted and centred etc. But maybe most modellers don't want that, and aren't prepared to pay for it. More to the point, maybe they don't want to pay for the potential in their Tx to do it - because they know that they never will!

 

So enter FHSS - a no frills 2.4 system without all the potential to handle the add on bits.

 

I suspect that FHSS was an after thought when they realised where they were headed with FASST. FASST is designed to keep them at the top of the market, its their "blue riband" product. FHSS is the "Mini" designed to give them a presence in the "ecomomy" market.

 

They can't make FASST cheap enough to compete at this end. But beginners are at this end. If Spektrum hoover up all the beginners with the DX6 say, Futaba could find that "brand loyalty" keeps those beginners with Spektrum when they move on. So Futaba need a Tx to compete with the DX6. That I think is the rationale behind the FHSS systems.

 

 

BEB

[Biggles' Elder Brother - Moderator]

Posts like this would tend to suggest that Futaba are right! There is a market for an economy 2.4 Futaba system - but it can't be FASST!

 

BEB

[kc]

The real question is about compatibility. The Ripmax Saturn is also described as FHSS and an extra Saturn 6 channel FHSS Rx is £19.99 which is only half the price of the Futaba FHSS 6 channel Rx ( also Ripmax of course ) Can we use these cheap Ripmax FHSS receivers with a Futaba FHSS Transmitter?

 

The point is the new Futaba FHSS T6J combo is about the same as a 6EX  FASST combo so  the other question is does this spell the end for the  6EX 2.4  Tx as an affordable FASST Tx?  Should we buy one now!

Edited By kc on 25/03/2011 11:05:59

[ken anderson.]

hello KC..the combo i was refering to can transmit on both of the freq's that futaba are selling...so i would have thought that would be the end of the road for the fasst tx only....?

 

 

ken anderson ne..1.

Edited By ken anderson. on 25/03/2011 11:12:02

[Biggles' Elder Brother - Moderator]

Not withstanding Ken's comment - which is fine cos they are both Futaba - I don't think you should not assume that any other two 2.4 systems are compatable - even though they are both described as FHSS. The detailled programming of any other two systems is likely to be completely different at a "nuts and bolts" level although they are both implementations of the FHSS protocol and both carry an FHSS badge.

 

FHSS is not like say PCM or PPM under 35MHz - the protocol is not that specific about how you actually relaise it inside the electronics.

 

So unless it explicitly states the two are compatable you should assume that they are not.

 

BEB

[kc]

Sorry Ken I think you are wrong! The new T6J says it's FHSS and S-FHSS but does not mention FASST. ( its the T6J Tx you are referring to I think )

Also the Futaba website says the FHSS receivers are not comatible with FASST ( what twit gave 2 such different systems them such similar acronyms!? )

And to confuse us even more if you look up the only FHSS Tx  on the Futaba site ( the T4YF ) it shows the details for the 6EX which is FASST.  Totally confusing and clearly wrong. How can the person responsible for this info retain their job in this day & age?

 

The comptability of FHSS and S-FHSS is shown with 4 different Rx but no mention of FASST. Lets not discuss S-FHSS at the moment only FHSS

 

I am sure BEB is right,  if you sort out his double negative. . Actually I am not planning to use a mixed system, but I am just being 'Devils Advocate' to find the info so we can all correctly advise newcomers. Very important before people spend their hard earned money. Why didnt Ripmax print the info we need in their brochure? Dealers should know this but dont always advise correctly. 2 of my club members have bought cheap 'compatible' 2.4 Rx on the advice of a retailer and then found they didnt work with Futaba as the seller said, but were for Spektrum!

Edited By kc on 25/03/2011 13:25:19

[ken anderson.]

sorry all--KC has put me right.....so FHSS and S-FHSS....we have looming....am i right in thinking that this is going to be the cheaper 'norm' for the average club flyer....because it must be obvious to futaba/ripmax that people dont want to pay the high price for the FASST...equipment ? ....

 

ken anderson ne....1(tech dept)..not.

 

 

[Biggles' Elder Brother - Moderator]

I think that is about the size of it Ken.

 

BEB

[Martin Harris - Moderator]

As a dyed in the wool Futaba user I must say that I'm worried that the move to high end systems exclusive to Futaba is rather like the situation back in the 70s when JVC found a way round the patent held by Sony's U-matic (Betamax) video system. The JVC system was technically inferior but Sony only licenced Sanyo to use U-matic (I don't know whether by policy or cost) with the result that the general availability of VHS videos killed Betamax.

 

It seems to me that Futaba could get more brand loyalty by licencing the technology but concentrating on upholding their reputation for quality, making the purchase of a Futaba transmitter worthwhile with the use of Futaba receivers for more important models being encouraged and accepting that other receivers would be used for some of a user's "cooking" models as was the case with dual PCM/PPM transmitters.

 

I say I'm a Futaba user - but I've already made the move to a Jeti module for my FF10 and I think it's very likely that when the time comes to replace or upgrade, I'm likely to consider moving to a Jeti transmitter (a range is just being introduced) as module systems are being phased out, presumably in a move to lock in users. If I'd been able to buy cheaper receivers for a good number of my smaller models I would probably have stayed with Futaba...

[Biggles' Elder Brother - Moderator]

But Martin in this respect Futaba are no different from any other 2.4 manufacturer - they are all different!

 

Futaba have FASST as their "top of the range" implementation and FHSS as their "economy" implementation. The two don't talk to each other.

 

Specktrum have had DSM then DSM2, now they have DSMX. While DSM and DSM2 are compatable - neither are compatable with DSMX as far as I understand. Nor are they compatable with the Futaba systems.

 

JR used to use DSM2 now they use DMSS their own implementation of 2.4. DMSS is not compatable with FASST, FHSS (Futaba), DSM/2 or DSMX.

 

Jeti call their 2.4 system DUPLEX which in turn is not compatable with FASST, FHSS (Futaba), DSM/2, DSMX or DMSS.

 

And so on....there is nothing specific to Futaba about this. It is both the advantage and the disadvantage of Spread Spectrum technology that it is so flexible. It only defines the basic outline - the manufacturer is free to "join the dots" as he likes. So every manufacturer's system is different!

 

BEB

[Tom Wright 2]

A Couple of years ago i took on the task of evaluating some very cheap 2.4 gear .

It is full range and cost around £40 including delivery ,binding was simple ,and ground range checks looked good ,first airborne experience was in a 2.5 m EP glider and over a three month period it was flown to the extreme including near out of sight range with the TX low volts warning light on ,any way to cut along story short i ended up buying a dozen or so receivers and installed them in a wide variety of models including twins ,3d, trainers ,gliders , and several semi scale jobs,and two years later i cannot report one fault or problem,i fly on average 5 days every week and reckon this gear has done at least 400 hrs , yet in the same period my spektrum and futaba had to be returned for repairs after less than 20 hrs use,.This really does make me wonder if all this rapidly escalating trend towards more and more bells whistles and extra chips featured in volumes of expensive glossy adds does anything to increase reliable flying for the every day club pilot ? i Think it certainly leaves many confused and at the mercy of dealers who often don't know either. Sorry if this is a bit off thread.

 

TW2.

[Martin Harris - Moderator]

BEB - I only picked Futaba as an example close to home and I'm quite aware of the incompatabilities between different makes. My point is that by keeping a tight rein on their proprietry systems, manufacturers are likely to lose market share, not protect it. In the days of 35 MHz PCM there was always the option to use whichever compatible PPM receiver you wanted.

 

Spektrum have opened up their market by getting involved with other suppliers to bundle DSM2 compatible receivers with products - I know, I was flying my Etomic Vapor and E-flite Blade MSR this evening with an E-flite DSM2 transmitter.

 

Whisper it quietly but I could be tempted into buying a Spektrum computer transmitter if I get many more of these "toys"...

[Tom Wright 2]

Just a foot note to my comments i have been a life long futaba fan and still am ,not quite so happy with the spectrum for various reasons, i wont bore you with the details,but my cheapy set has proved to be the most  reliable,and certainly the least confusing.

 

TW2.

Edited By tom wright 2 on 26/03/2011 02:53:47

[David Ashby - Moderator]

 

Specktrum have had DSM then DSM2, now they have DSMX. While DSM and DSM2 are compatable - neither are compatable with DSMX as far as I understand. Nor are they compatable with the Futaba systems.

 

 

Excellent posts and summaries BEB.

 

Just though I'd clarify that DMSX is backwards compatible so it'll operate with DSM2 receivers. Looking at the new 2011 Spektrum catalogue, I was struck by how everything is labelled DSMX - radios, receivers the lot and, significantly, even items like the DX5 Tx - DSM2 versions of which can't be converted to DSMX.

 

I was always surprised when Multiplex and Hitec went separate ways (they're the same company) and developed their 2.4 systems independantly - a commercial decision I guess.......

 

Sadly, while 2.4GHz radios are wonderful things, the 2.4 arena hasn't exactly simplified the choice for modellers!

 

 

 

 

 

 

 

[Pete B]

Posted by David Ashby - RCME Administrator on 26/03/2011 06:21:31:

 

Specktrum have had DSM then DSM2, now they have DSMX. While DSM and DSM2 are compatable - neither are compatable with DSMX as far as I understand. Nor are they compatable with the Futaba systems.

 

 

Excellent posts and summaries BEB.

 

Just though I'd clarify that DMSX is backwards compatible so it'll operate with DSM2 receivers. Looking at the new 2011 Spektrum catalogue, I was struck by how everything is labelled DSMX - radios, receivers the lot and, significantly, even items like the DX5 Tx - DSM2 versions of which can't be converted to DSMX.

 

 

Not only backwards but forwards compatible, too, David - DX5e, 6i and 7 can all use DSMX Rx's, which should keep most Spekky users happy. I'm not sure that all Futaba users will be quite as happy, though..........

 

Pete

[Ultymate]

No insult intended to the original poster here but I just don't see the point in threads of this nature, if you have a PC with internet available surely a topic like this can be researched by typing Futaba into Google. From the moment these threads start they degenerate into Futaba V JR/Spektrum nonsense which has been and will be debated ad nauseum .

[ken anderson.]

ultymate i think the answer for you is in the title of the thread...the lad is asking a question to other members for some feedback and info...is that not what the forum exists for -to exchange view's and info?...help others ...

 

oh and by the way futaba is best.....

 

 

ken anderson ne..1.

[Tom Wright 2]

Yes i agree KEN the discussions can create a greater depth of understanding , after all google info is static this forum is dynamic.

 

TW2.

[kc]

Ultymate should take a dose of his own medicine  and read the Futaba website found by Google . He will see that not only does it fail  to answer this question but that it has a very misleading error as I indicated above!  We are not arguing the merits of any brand ( well only  Ken is ! ) but sorting out compatibility for everyones benefit,

 

The question still to be answered is ..........adverts for Futaba, Saturn and Sanwa all use FHSS in a similar way almost a logo, all in the Ripmax New Item catalogues, but are they compatible?   If not why dont they make it clear!    (

 

Could we know the brand of the cheap 2.4 sets that Tom found  so reliable?

 

Edited By kc on 26/03/2011 18:33:53

[ken anderson.]

hello KC......the planet 2.4 ghz is getting good reports......for the price...the rx's are around about £15.00..and the latest TX is a 6 channel......i would say it's ideal for a foamy on the slope or even a park flyer....as for the more expensive types of models..with the large motors in and a lot of dosh parted with...i would say then you need the top end gear.....which us(me) poor pensioner's can only dream about or drool over when the likes of young asher's and co are running around with them..... ....

 

 

ken anderson ne..1(financial cramp dept).