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Old 03-31-2013, 11:11 PM   #1 (permalink)
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Default JETI Signal Specs Vs. Futaba Vs. Spektrum???

I have spent all day looking hear and all over the web for any info regarding the specs for the 2.4 transmission.

I am really interested in possibly buying one of the transmitters, but I would like to know more information about the signal that is being transmitted versus say the Futaba FASST and the Spectrum DSMX signal.
My reasoning is the reported lock-outs at the big events.
Is the Jeti signal robust at rejecting interference? Any known info would be greatly appreciated!
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Old 04-01-2013, 06:01 AM   #2 (permalink)
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I would say that there is no need to worry. I go to a lot of events including IRCHA and there hasn't been any confirmed lock-outs at any event that have been verified. AMA would be all over any proven lock-outs since their insurance companies would be raising a stink.

I don't think that you will find much on the actual transmission protocol as like most systems they are proprietary and meet US FCC requirements for use within the 2.4GHZ transmission band. This is very strenuous testing as evidenced by the amount of time required to get a transmitter approved. Just ask Jeti
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Old 04-01-2013, 07:54 AM   #3 (permalink)
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Default JETI Signal Specs Vs. Futaba Vs. Spektrum???

Pretty sure that Jeti was a leader in 2.4ghz in the RC industry anyway...(?)
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Old 04-01-2013, 07:58 AM   #4 (permalink)
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Quote:
Originally Posted by Seasick78 View Post
Pretty sure that Jeti was a leader in 2.4ghz in the RC industry anyway...(?)
Not to mention it actually has two modules in the radio. No idea on latency comparison, but these days any high end radio is going to be faster than most people are even capable of noticing the difference of. That was more of something people used to go on and on about a few years ago. Not talking about buying some POS and then comparing it to Futaba. I am talking about high end radios in general.

Last edited by BustedRaptor77; 04-01-2013 at 07:59 AM.. Reason: typo
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Old 04-01-2013, 08:15 AM   #5 (permalink)
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Default Spunds Good.

That sounds pretty reasonable. However, I started thinking about another aspect...

Does the transmitter send the individual signals to, say the cyclic servos on helicopters, all at the same time? I know the Spektrum system has the servo match, or something like that, and Futaba sends the first 6 or seven channels at the same time. I have heard that the lower quality systems will still send the signals one at a time, thus reducing the accuracy. (I am not saying JETI is lower quality, I am just saying in general).

Also, what is the reported latency of this system?

Sorry for so many questions, I just like doing research before I plunk $1600 on a radio.
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Old 04-01-2013, 08:16 AM   #6 (permalink)
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Default Sounds Good.

That sounds pretty reasonable. However, I started thinking about another aspect...

Does the transmitter send the individual signals to, say the cyclic servos on helicopters, all at the same time? I know the Spektrum system has the servo match, or something like that, and Futaba sends the first 6 or seven channels at the same time. I have heard that the lower quality systems will still send the signals one at a time, thus reducing the accuracy. (I am not saying JETI is lower quality, I am just saying in general).

Also, what is the reported latency of this system?

Sorry for so many questions, I just like doing research before I plunk $1600 on a radio.
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Old 04-01-2013, 08:18 AM   #7 (permalink)
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Default Sorry for the double post. I forgot to hit the refresh button!!!

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Old 04-01-2013, 08:23 AM   #8 (permalink)
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The protocols of how the signals are transmitted are completely different from radio brand to radio brand, and how they do check sums etc. If you want to understand how it works go poke around in a robotics forum.
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Old 04-01-2013, 08:27 AM   #9 (permalink)
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I would say that Futaba has the most sophisticated method for handling data packets with FASST and FASSTEST, but I have no idea how Jeti works.
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Old 04-01-2013, 08:43 AM   #10 (permalink)
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Here is what you are trying to compare JR/Spektrum make hobby stuff, Futaba makes sophisticated remotely operated industrial equipment and hobby stuff, and Jeti hasn't been around long enough for super smart people who know how to analyze the system properly. So unless some official Jeti person comes on here and posts about a 20 page dissertation on Duplex EX you will just get people guessing and who are fans of one product or the other.
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Old 04-01-2013, 10:11 AM   #11 (permalink)
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Default Well Said. Point Taken.

Quote:
Originally Posted by BustedRaptor77 View Post
Here is what you are trying to compare JR/Spektrum make hobby stuff, Futaba makes sophisticated remotely operated industrial equipment and hobby stuff, and Jeti hasn't been around long enough for super smart people who know how to analyze the system properly. So unless some official Jeti person comes on here and posts about a 20 page dissertation on Duplex EX you will just get people guessing and who are fans of one product or the other.
Yeah. A very true statement indeed. I think I will continue using my Futaba 12FGH and JR 12X for the BNF stuff. I will wait and see (or read) about other people's experiences with the JETI stuff. The $3,000 price tag on the Futaba 18 is ABSURD!!! I was a Futaba fan until this price tag came out.

If Jeti does it right and floods the market with their stuff, these units are going to fly off the shelves. I just hope they can stay in this market to shake things up ALOT!!!
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Old 04-01-2013, 10:17 AM   #12 (permalink)
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It would be interesting if the gentleman at rcmodelreviews could get his hands on one of these units. He will show the good, the bad, and the ugly of all the systems.
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Old 04-01-2013, 10:19 AM   #13 (permalink)
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Quote:
Originally Posted by newtek007 View Post
Yeah. A very true statement indeed. I think I will continue using my Futaba 12FGH and JR 12X for the BNF stuff. I will wait and see (or read) about other people's experiences with the JETI stuff. The $3,000 price tag on the Futaba 18 is ABSURD!!! I was a Futaba fan until this price tag came out.

If Jeti does it right and floods the market with their stuff, these units are going to fly off the shelves. I just hope they can stay in this market to shake things up ALOT!!!
I'm not one of those super smart people. I am the one who reads what those people post and understand about half of it. With that said the 18MZ $ comparison to DS-16, and out of the box functions are the big things that made me buy a DS-16 before it was even released.
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Old 04-01-2013, 10:32 AM   #14 (permalink)
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DSMX 2048 steps 11ms frame rate
Fasstest 4096 steps 8ms frame rate
DMSS 4096 steps 11ms frame rate
Jeti Duplex 4096 steps XXms frame rate

FWIW the DSMX DX18 has varying frame rates for different channels and all of the frame rates drop depending on the number of channels used.

As I understand it the Jeti Duplex system actually has a configurable frame rate. I think it defaults to 20ms to handle all 16 channels, but I'm not sure about that.

What we don't have are latency measurements that are typically dependent on the speed of the processor in the TX. The DC/DS -16 transmitters appear to have an abundance of CPU speed.

For example some Futaba and JR TX's have a very long latency so that the frame rates are not indicative of how fast the heli responds. You can lose 15-30ms due to transmitter processing before the values are transmitted.

So remember that the frame rate is just the transfer protocol and the actual response varies by transmitter.

With regard to how the channels are transmitted. DMSS made a big deal out of sending all the cyclics together, however this ONLY matters for helicopters with flybars. FBL controllers get all of the cyclic inputs and then process them together no matter how they are sent so this really doesn't impact anything.

Fasstest and DMSS are the two protocols that hold up to Jeti's full duplex protocol and don't require an additional box to send back telemetry like the TM1000 used with DSMX.

For telemetry the Jeti solutions is currently the most refined.

Examples:

Fasstest Jive ESC -> JLog -> JSend -> Futaba transceiver <-> S.Bus FBL controller

Simpler
Jeti Jive ESC -> JLog -> Jeti transceiver <-> PPM FBL controller

Simplest
Jeti Jeti Mezon ESC -> Jeti transceiver <-> PPM FBL controller
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Old 04-01-2013, 10:47 AM   #15 (permalink)
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Default Excellent info!!!

Now were talking!

I have just poked around on other sites and found a discussion that the older Jeti Systems used only 16 channels in the 2.4 band. I know nothing of European systems, so I do not know if this true. It is reported that the Futaba system uses all of the 81 or so bands (not sure of the exact number).

Please remember all, I am not bashing any one system. I am just trying to collect technical info to allow for an "educated" HaHaHa purchase. I REALLY like the JETI stuff, I just like "looking under the hood" before I buy.

Thanks to all for your replies. This is some very good information.
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Old 04-01-2013, 11:43 AM   #16 (permalink)
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I have never had an interference issue even with my infamously horrible DSM2 stuff since switching to a 2.4 ghz transmitter. Some of the things you read about it would lead you to think it is completely unsafe to even fly with it. So I doubt that I would have any problems with new state of the art technology either.

I know others have had problems with DSM2 especially at funfly events where there a bajillion people with them on, but I have never run into anything.
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Old 04-01-2013, 11:50 AM   #17 (permalink)
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Quote:
Originally Posted by newtek007 View Post
Now were talking!

I have just poked around on other sites and found a discussion that the older Jeti Systems used only 16 channels in the 2.4 band. I know nothing of European systems, so I do not know if this true. It is reported that the Futaba system uses all of the 81 or so bands (not sure of the exact number).

Please remember all, I am not bashing any one system. I am just trying to collect technical info to allow for an "educated" HaHaHa purchase. I REALLY like the JETI stuff, I just like "looking under the hood" before I buy.

Thanks to all for your replies. This is some very good information.
I believe that there are only 80 total frequencies allocated to RC use in the 2.4GHz spectrum.

Basically these are all hybrid FHSS DSSS systems.
I believe that Airtronics is the only transmitter to just use a standard FHSS protocol.

DMSS uses 10 frequencies (2405MHz to 2450MHz) of the ISM band, using 802.15.4
DSMX hops between 10 free frequencies and uses two at a time.

FASST claims to flip frequencies faster than DSMX and have better error correction ( 500 times per second ) but also is using 2 frequencies at a time.

FASST has a 16bit Guid

DMSS utilizes a 64bit Guid to identify the model which is being used which seems like overkill, but I think they have bragging rights for the number of Guid bits used. However this is not where the issue is at an airfield.

I believe that Jeti uses a 32bit Guid ( but I don't remember where I read that )

Remember too that the Jeti DS-16 has two completely redundant transmitter/receivers with two antenna each that are both active, so you have redundancy. They have to be working on multiple frequencies simultaneously. The question if they are using 4 at a time rather than the 2 at a time other protocols employ.

No other transmitter on the market has the feature of redundant transmitters and antenna. Jeti says that they will seamlessly switch back and forth if one loses connection and the other has a connection.
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Old 04-01-2013, 11:56 AM   #18 (permalink)
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FWIW I've complained about blinking DSMX satellites, but have never actually lost connection either.

I really don't think any of these protocols is inherently flawed, although it appears Spektrum has had the most issues because of their hardware and not the DSMX protocol itself.

From what I understand, I would currently rate the protocols like this.

I would consider this a tight grouping.
1. DMSS
2. Fasstest
3. Jeti
4. Fasst
5. DSMX

Based on their transmitter hardware I would rate the systems like this.

I think Jeti has a huge lead in terms of their hardware's ability.

1. Jeti

( serious functionality gap )

2. Futaba / JR
4. Spektrum

I think JR's latest DMSS transceivers with a serial communication stream will allow them to catch up with Futaba.
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Old 04-01-2013, 12:12 PM   #19 (permalink)
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Quote:
Originally Posted by mkovalcson View Post
FWIW I've complained about blinking DSMX satellites, but have never actually lost connection either.

I really don't think any of these protocols is inherently flawed, although it appears Spektrum has had the most issues because of their hardware and not the DSMX protocol itself.

From what I understand, I would currently rate the protocols like this.

I would consider this a tight grouping.
1. DMSS
2. Fasstest
3. Jeti
4. Fasst
5. DSMX

Based on their transmitter hardware I would rate the systems like this.

I think Jeti has a huge lead in terms of their hardware's ability.

1. Jeti

( serious functionality gap )

2. Futaba / JR
4. Spektrum

I think JR's latest DMSS transceivers with a serial communication stream will allow them to catch up with Futaba.
Agree with this completely, and the first list really has to be taken with a grain of salt cause the bottom is probably about bullet proof to begin with and the top 2 are just going over the top with security.
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Old 04-01-2013, 12:30 PM   #20 (permalink)
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Default JETI Signal Specs Vs. Futaba Vs. Spektrum???

Quote:
Originally Posted by newtek007 View Post
It would be interesting if the gentleman at rcmodelreviews could get his hands on one of these units. He will show the good, the bad, and the ugly of all the systems.
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