Advice needed. 6/8J vs 8FG/14SG

[spykez]

Short story; bowled over by how good the 6j felt with my trex 250 3g mrs.

Easy to program, felt better than a dx8 even for my thumbs, and I thought the spekky gimbals were nice.

Questions:
1. How fast is s-fhss? Frame rates quoted 6.8 - 13ms for full delivery of 8 channels. What is the true latency of this protocol?

2. How does this compare to FASST, FASSTEST, would seem like 12 channel fastest is top of the hill? Or is it still 7 Chan fasst the best?

3. I can get an 8 j (but tower has discontinued them), or make do with my 6j. Much cheaper than an upgrade to an 8fg or 14sg.

I mean if s-fhss is just about fast as fasst/er (or maybe faster?) why not stick with s-fhss?

Simple heli (only!) flying, brain be the most exciting thing I'll have aboard. Thinking s-bus here.

Thanks for your opinions.

[HilliHeli]

There are some differences in the (2) types-of protocol (see here) ;

http://www.futaba-rc.com/technology/fhss.html

vs.

http://www.futaba-rc.com/technology/fasst.html

[spykez]

Thanks, saw that.

Really was wondering if an 8J was just about enough with S-FHSS rather than to go with a 14SG or 8FG.

If S-FHSS is squeezing out 6-8 channels in one frame of 6.8ms or even between two frames for a complete update, that would imply a really low latency.

What are comparisons of FASST, FASSTEST and S-FHSS? I think there was a RR thread going back years that recently upated itself with the 14SG but no figures on the S-FHSS protocol radios.

I don't expect telem. All I want is 6 channels to my v-bar, maybe 7 if I want to try self level with a brain. Simple needs.

PS - I am now aware of some limits of the 6J - no apparent stick calibration for one, possibly the biggest problem, but not that much an issue I guess with v-bar.

PPS I also know the 8J is discontinued at tower at least... why I don't know.

[dvelez3]

Originally Posted by spykez

PPS I also know the 8J is discontinued at tower at least... why I don't know.

Perhaps because the 10j with telemetry is due out soon.

Doug

[spykez]

Dumb question, but are the 14Sg and 8fg (and 8j) smaller than a DX8?

Is the 6j somewhat similar in size to the 8j?

Thanks again

[boogie12]

Originally Posted by dvelez3

Perhaps because the 10j with telemetry is due out soon.

Doug

Wait they are releasing a 10j? Do you have a link I have the 8j its a nice radio I have only had it for about a year.

To the op the 6j and 8j are similar in size the 8 just has more channels.

[dvelez3]

Futaba 10J at AMA Expo 2014 (2 min 47 sec)

Doug

[spykez]

Originally Posted by boogie12

Wait they are releasing a 10j? Do you have a link I have the 8j its a nice radio I have only had it for about a year.

To the op the 6j and 8j are similar in size the 8 just has more channels.

Thanks man, I don't need telemetry and the added b/w of 10 channels.

Is the 14 SG any bigger or wider? Very happy with dimensions of t6, you see.

I might just find a heli 8j if the 14SG is more massive and if someone could tell me more about all this frame rate marketing stats.

If the 8j guarantees me a full refresh in two 6,8 msec frames, I would like to know what FASSTEST actually brings to the table (besides telemetry and more$$$)

[dvelez3]

FASST/FASSTest will give you a robust FHSS/DSS hybrid system while the Futaba S-FHSS gives you a FHSS system with very narrow channel spacing and no error checking and correcting.

Doug

[spykez]

Originally Posted by dvelez3

FASST/FASSTest will give you a robust FHSS/DSS hybrid system while the Futaba S-FHSS gives you a FHSS system with very narrow channel spacing and no error checking and correcting.

Doug

If I fly out in the country and there is low levels of background microwave chatter, which is the faster system? I know it's a trivial question, I am not likely to notice, but I am curious.

I have not found any one done any specific comparisons between s-fhss and FASST/FASSTest etc. Just curious about numbers.

Costas, wanna give it a go? I don't have the know how.

[HilliHeli]

See the link I PM'd you, those graphs really show the differences.

[spykez]

Thanks, you know guys, I'll probably grit my teeth, spend the $$$ and just get the 14SG when I can afford it, can't hear the effing timer on my 6J for nuts...

Receivers aren't gonna be cheap though lol... And it seems the FASSTest ones are all out of stock lol.

[Costas]

Good question regarding latency between the transmitting modes. One thing to keep in mind is that latency is generally not all that affected all too much by what mode we transmit with - It is really primarily affected by the on-board processing power of the Tx's encoding stages as well as the Receiver's decoding chipset.

S-FHSS is marketed as a cheaper feature from Futaba's perspective. The radio sets and receivers that are sold as S-FHSS sets are cheap and therefore tend to be manufactured with lower spec devices [CPUs etc]. Do not confuse lower spec with lower quality - By lower spec I mean less featured and more than likely not as capable as far as processing is concerned.

I have not seen any latency figures for S-FHSS modes but I would guess that they would be worse than FASST only because of processing limitations as alluded to above. I could be wrong though...lol

You may have already seen my review on the 14SG. In that thread there are some spectrum analyser plots where you can see the difference between the three Futaba modes [as far as spectrum use is concerned]. http://www.archeli.com.au/forums/sho...d.php?t=159371

John [JKOS on Runryder] has done some latency measurements with the 14SG using a 7008 Rx. results are very good and its the quickest of the bunch of radios he has tested. http://rc.runryder.com/helicopter/t172571p1/

Note that the receiver has a large influence on overall latency as well - Its not just the Tx that counts.

Also Flybarless units add latency to your system which no one has measured, So while you may have sub 10mS figures for a particular radio system, adding a FBL unit into the mix could blow this figure out of the water anyway.

I wouldn't get too hung up on latency figures as most recent radios are pretty good anyway.

[spykez]

Yea, read your great review and the rr tables, thanks Costas. Sasefcharisto! (did I get that right?, lol)

[Costas]

Close enough...

[al93535]

I had the 6j, and bought the 14sg. I use the 6j on my sim and the 14sg for flights. I still use S-fhss though on all my helis. Cheap receivers that just always always work. I haven't installed the fastest rx included with the radio.

The 14sg Does feel different in the hands. Of course it's heavier and a wee tiny bit bigger. Both feel great though. Love love love the gimbal s on the 14sg.

sent from a non Apple device

[Atomic Skull]

One advantage of the S-FHSS is this:

http://www.valuehobby.com/frysky-delta-8.html

If you're wondering how they did this, it's because Futaba, Frsky and Hitec all use the same off the shelf radio chip so making them talk to each other is just a matter of software. It's actually just a FrSky V8FR-II receiver with multi protocol firmware.

[al93535]

I'm only using as of yet S-fhss recievers with my 14sg.

sent from a non Apple device

[RC Mike]

Originally Posted by Atomic Skull

One advantage of the S-FHSS is this:

http://www.valuehobby.com/frysky-delta-8.html

If you're wondering how they did this, it's because Futaba, Frsky and Hitec all use the same off the shelf radio chip so making them talk to each other is just a matter of software. It's actually just a FrSky V8FR-II receiver with multi protocol firmware.

That’s not really an advantage. With FrSky you can get the superior reliability of FASST at a reasonable price. I have several sizes of these receivers and they are all just as good as genuine Futaba. http://www.alofthobbies.com/radio-ge...ompatible.html