FlyingGiants Exclusive! Introducing The Futaba 12FG, Modules & More!

[wollins]

subscribed

[Boulder]

	Quote: Originally Posted by Windecker
	Not positive, but I think the ppm is like 1024 speed. Might need to cross check that though. The new 2.4 FASST speed as stated in several areas above is similar to the 2048 speed which is very fast. Switch from 1024 to 2048 and you will under snap your snaps till you get used to the faster speed. Will B.

Hey Will,

Like you, I'm not 100% positive, so I will need to defer to the experts. My input was strictly from my understanding of the systems, not an extreme expertise in the matter.

I'll patiently wait the answer from the pros.

[KatManDEW]

Will there be a micro receiver for indoor aircraft?

[Dantley]

And I was going to sell my 14mz. Not anymore.

[notorious_benny]

What is the difference between PPM and PCM?
PPM stands for Pulse Position Modulation, and PCM stands for Pulse Code Modulation. Here is a basic comparison between the current crop of receivers on the market.

PPM
Our traditional "FM" is still a framed signal that the rx processes. The only difference is that it is an analog based signal. So what happens is that any signal received within the "frame" for that channel is processed. This is the famous glitch where the servos are sent screwy for an instant.

The advantages of FM are low cost. Also the resolution (in theory) can be very high because there is (theoretically) no loss of signal during the conversion to digital. This is only true with analog radios, though. Digital radios put PCM and PPM on a level playing field as far as resolution goes.

Disadvantages -
The "glitch". This spastic movement of the servos when a bad signal is decoded is why many people prefer to switch away from traditional PPM. Also the resolution that many of the older radios had is removed by the new "digital" txs that use only 512 or 1024 bits of resolution. But to be honest, that is a minor problem and most people would never see it.
Slower Refresh rate - A PPM Rx sends a signal to the servo once every 20-25ms. A PCM Rx sends pulses almost twice as often. This is true with my Futaba systems--I have measured it with my oscilloscope.

PCM
PCM is still broadcast on the FM carrier wave. But instead of using a PPM frame setup, a digital stream is created of x bits (1024 for most). The digital stream consists of a header, a trailer, a set of parity bits, a failsafe section, and the actual control section. The receiver takes this stream/word and decodes it into the control positions based on the position in the stream. Since a small microcomputer is in the Rx, quite a bit of processing can be done during this section.

Advantages -
No more glitch! While the same bad data is received by the RX, the microcomputer has the smarts to reject that bad data and not move the servos. So for that instant you simply don't get movement of the servos. For 99% of the people out there, this is the only reason they switch to PCM! Another advantage is better control of certain surfaces. On PPM, all channels are of equal value.
Faster refresh rate - While a PPM Rx only sends out a servo pulse once every 20-25ms, the PCM Rx's are almost twice as often, at about 10-15ms. For Futaba gear, anyway, the thought that PCM's have slower refresh time is a myth! I have measured it with my oscilloscope.

Disadvantages - There are several so I will list them:
Proprietary - Each company's PCM is only compatible with PCM rxs and txs of their own make. Most aftermarket rxs will not work on proprietary PCM txs. So your are locked in to one brand or even one rx!

Slow response time compared to PPM. The actual data stream is larger (2- 3 times) the size of PPM. Many pattern fliers used to switch to PPM simply because they felt the added speed of PPM helped them. I know that on one of my giant scale planes I can tell the difference between the PCM update and PPM update. Only one plane, but there is a difference. Note that I have not yet checked this to verify it.

lower resolution. On systems that output pure analog PPM, the resolution is higher on PPM than PCM. But for most of us this is not a problem. And for the killer! The PCM lockout. When the PCM rx gets too many bad packets it then goes into a lockout or failsafe position. This continues for several refresh cycles after a valid packet is received. Most are around 1 second long before control is returned. It is this lockout that has most heli fliers staying with PPM! imagine hovering and having the system lock out for a second. A glitch can be just as bad, but at least then the control is instantly returned and not held up for a second or so. On the other hand, PCM lockouts are FAR fewer and much farther between than PPM glitches.

http://www.rcfaq.com/ANSWERS/RADIO/INDEX.HTM

The above is all just cut and paste.

[Kiwi]

	Quote: Originally Posted by Judge
	Not sure this got posted yet (probably did) but here it is again to keep it current: Futaba FASST!!!!!!! details here: http://2.4gigahertz.com/radios/futk9275.html http://2.4gigahertz.com/modules/futl7637.html This is such a cool thing, I'm figuring out right now just how much I can afford!! Defintely a module for the 14MZ and several 14 channel RXs. And what the heck, maybe a 12FG just cause it looks so damn cool!!!!! Team Futaba

Judge,

Just off the horn with Futabaman trying to make sure you team guys dont get them all. I have been told he who grovels the most and greases the palm comes out a winner. I'm in need a 12 because my 14MZ case is the old style and has room for two sets. The poor old 14 likely feels a bit lonely in that big old case so if I buy it a sister it might just perform better.

Thats my theory and I'm sticking to it.

Kiwi

[3dubya]

One word

Dang!!!!

friggen awsome....

[Tor]

	Quote: Originally Posted by Boulder
	Yep Benny, That's the way I remember it.

Yes, but PCM-G3 is faster than PCM and PPM.

Installing a module that communicates with the TX using PPM is a step in the wrong direction.

I annoys me that Futaba does not provide this information. If it indeed use PPM, one might just aswell choose Spectrum modules.

[50%plane]

WOW! What an awsome announcement! Thanks Max for posting this. I can't wait to upgrade my 9C.


50%

[crhammond]

	Quote: Originally Posted by Tor
	Yes, but PCM-G3 is faster than PCM and PPM. Installing a module that communicates with the TX using PPM is a step in the wrong direction. I annoys me that Futaba does not provide this information. If it indeed use PPM, one might just aswell choose Spectrum modules.

I thought the post BAX made back to me was pretty clear for the 12Z/14MZ... it is native FASST - which is totally different from PPM and PCM. The shape of the "module" does not look like it simply replaces the current module either.

If you want to know on the other series radios I bet if you post on the RCU Futaba support forum they will answer. It would be nice if they did that here on the giants... but I have always had really good support and fast responses on their forum on RCU.

Maybe someone can post int he Futaba fliers club too? I am still waiting for my registration.

Anyway - Toledo will be very interesting for sure. I bet JR will have something as well. Soon we're gonna be overwhelmed with choices!

[Tor]

	Quote: Originally Posted by crhammond
	I thought the post BAX made back to me was pretty clear for the 12Z/14MZ... it is native FASST

I don't see that at all. No mentioning of native anywhere. I'll ask my question in your thead on RCU.

	Quote: Originally Posted by ORIGINAL: Bax
	You'll only have to plug in the module and you'll be on the 2.4 FASST system. You'll be able to use all of the FASST airplane receivers with your transmitter.

[notorious_benny]

Shiny new twin cylinder motor ........... $2600

Big shiny comp-arf extra .............. $4000

10 high torque digital servos ................ $1400

carbon propellor ....................... $170

Being immune from being shot down by the geriatric pensioner who shares your frequency ................................. priceless.

Disclaimer. The above prices are approximations in Australian dollars.

[Tweaker]

Well if PPM causes the channel limit to be 8 i think it's obvious they are not using PPM, The picture of the new radio clearly shows PCM G3 PCM 2048 2.4 GHZ.Later it says modules turn 12z 14mz into FASST 2048 2.4 GHZ with more features than the 12FG offers. I assume the 9C may be limited to 1024 resolution as that is what it transmits. I even thought I read the new module uses PCM.

[Judge]

	Quote: Originally Posted by KatManDEW
	Will there be a micro receiver for indoor aircraft?

The 6-channel RX that comes with the 6EX is tiny, barely big enough for the plugs. It wll work fine in a park flier.

[KatManDEW]

	Quote: Originally Posted by Judge
	The 6-channel RX that comes with the 6EX is tiny, barely big enough for the plugs. It wll work fine in a park flier.

Thanks for the info.