a1pcfixer

My Feedback: (7)

To ALL,

Who's taking advance orders on the Futaba items?
Best discounted prices?

arobatx

DCT129

Where can you buy a radio that will modulate PPM, PCM, and with a quick module change out it will modulate Spektrum 2.4 for 239.99-299.99?

kev71h

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Gary Arthur

My Feedback: (29)

If I am not mistaken, the update for the 14mz includes a 12 channel PPM update. This would give 12 channels in PPM. Here is the info from the the update.

2. Model select
2-1. Back to starting up screen when changed the model.
2-2. Back to starting up screen when new model is made.

3. PPM modulation (for Europe and USA version only)
3-1. Added the modulation polarity selection at PPM mode.
3-2. Added 12 channels PPM mode.

The additional dialog box appears when set the PPM modulation. Push the upper side button to select the PPM polarity. The Standard PPM corresponds to FUTABA receivers. Push lower side button to select the PPM channels. There are 3 kinds of selections, 8ch PPM, 12ch PPM (N 1.5), 12ch PPM (N 1.3). N means neutral pulse width.

dubd

Given that the 14/12MZ can transmits 12 channels on PPM, are we still restricted to 8 channels with the module? Can a Horizon rep answer this question?

On a side note, Futaba needs to get their butts in gear. Their 2.4ghz release is pathetic.

nonstoprc

My Feedback: (90)

Hi Mike,

ServoSync probably is one of the best features out of a Spektrum radio system. Just wonder how bad it can be for two elevators to keep in sync WITHOUT the servoSync feature in a Spektrum module system? Do we get the same delayed response of one of the halves as in a Futaba 9C radio?

Can servoSync be added to the Spektrum module product?

--qc

nonstoprc

My Feedback: (90)

Hi Mike,

I asume in that 2ms, the Skecktrum receiver will discard the futaba signal and maintain the same servo position(s), Right? I believe this type of response is true for any other type of interferencing FHSS signals.

If 2ms is not long enough to trigger the fail-safe feature, what is the duration (in ms or sec) of interference that will trigger it?

Does the 80 channels that Spektrum uses cover the entire 2.4Ghz band (i.e., from 2400mhz to 2483.5 mhz)?

Thanks, -qc

Mike Sieniarecki

My Feedback: (3)

riotgear,

The Spektrum air modules designed to fit Futaba radios, both traditional and MZ series, only use the eight PPM channels available.

Mike Sieniarecki

My Feedback: (3)

Nonstoprc,

Love the user name BTW �

ServoSync is a software based feature, and it can’t be added to the module system. I hear you though, it would be nice. I guess we can’t have it all, well for now anyway hee hee

Take care,

Fly Dog

Hello! i have see the new Recivers from Spektrum in the Bulettin,an i hope i can find any Answers? Then this Recivers going for the JR X-3810 too, Is the Distance the same with org.Recivers nearly one Mile?,what for SPMC,PCM,PPM is going? Sorry for my Bad English!!,im come from Germany and i have not reed the kompl.Thread! Thanks bevor Karl from Germany?

Mike Sieniarecki

My Feedback: (3)

Nonstoprc,

Correct on the first statement.

We have not tested the Futaba system, so its hard to say how theirs will perform yet.

Fail safe, at least with Spektrum systems, is based on a certain amount of data packets lost, so that time is no where near that.

Our Spektrum system is limited to 80 channels within the band.

Mike Sieniarecki

My Feedback: (3)

Fly Dog,

Hi from the other side of the planet.

Yes, the module system will work with that radio, and you can expect the distance to be the same or better than your current range.

JuanPu

1 - The fact that a Futaba FHSS radio coincides in frequency with the DX7 does not necesarily mean that the signal is lost for the DX7.

This is a neat property of DSSS: the data is scrambled with an apparent noise that only the receiver is able to remove with the same code that was used to generate it. If another signal is added to the received one, this only slightly worsens the S/N ratio in a "graceful degradation" that may, or may not, result in bit errors that are easily corrected with the extra parity bits that travel with the data (sort of ECC bits in PC memories), or that just means a packet is discarded in the worst case. The final result is that the mean data rate may slightly decrease, but there still is plenty of room for RC.

Of course there is a "near-far" problem where the added signal, if much stronger than the desired one, may totally obsure this last one. But this should not happen with the planes flying and both signal sources on the ground.

2 - Futaba with its FHSS may on the other side totally loss a packet while conciding with a DX7 channel, until it hops, since it uses "narrow bands across a wide band".

3 - The problem that I see here, and I'd like to see addressed by Horizon/Spektrum is:

Could a Futaba FHSS travelling across all the existing bands be able to preclude a Spektrum DSM2 system finding a couple of free channels at power on?

This is a very easy test that must surely have been done in the past months.

visioneer_one

My Feedback: (506)

This is quite a popular thread.

I wonder if the modules will work with a Japanese-spec 12X? (grins, ducks & runs)

Mike Sieniarecki

My Feedback: (3)

JuanPu,

The Spektrum system will simply continue to scan until it finds two unused channels. In other words, The Spektrum system will not acquire any channel that is not free at the time of scanning, so the FHSS will not affect SPM when it is turned on.

JuanPu

I have not expressed myself right. The question is:

If for instance, while looking for a free channel, the Spektrum waits in each channel more time than the used by a FHSS system to scan the whole set of channels, it could see a collision and discard this channel. And this would happen for each channel, precluding the Spektrum operation.

If the Spektrum system does not wait for such a long time in each channel, and/or if, on the other side, it waits in every channel enough time as to allow hopping of the other radio, this problem should not happen.

I don't ask for a technical explanation of the proprietary algorithm used, just if Spektrum switching on in the presence of a Futaba FHSS system has been tested or not, and what were the results.

Thanks in advance.

pappy35

Does't the FCC require that, in order to operate in that piece of spectrum (note correct, not brand, spelling), the transmitter not emit on a channel that's already occupied? If correct, this removes this entire line of spekulation and assures me that I don't have to worry about a Futaba radio squashing my signal for that 2ms.

Bob Pastorello

My Feedback: (198)

That's it.

d_wheel

My 14mz has 12 ppm channels. When are you going to produce a module and receiver that will let me use them?

Later;

D.W.

NormS

Mike, please understand that I have no axe to grind here, I'm simply looking for information. In that regard, your response has helped me understand how the things work, and I guess that the worst thing that should happen is that a Spektrum system may take a little longer to sync up in the presence of hopping systems, but only if it happens to be checking a channel that a Futaba system has hopped on to, and only if it sees the collision as interference.

Concerning the GUID business, I'm sure that the unique ID code will keep a receiver from responding to a non-errored frame from a different transmitter. The question, however, is what happens if someone hops on to one of the Spektrum's channels, and I think the answer is simple radio theory: they will interfere with each other on the RF level to an extent dependent on the relative signals strengths of the two signals at the receiver(s); both transmit frames are likely to be affected. This is the way radio transmission works, regardless of the frequency or modulation (AM, FM, PM, etc). However, this should not be a big deal because it sounds like the Spektrum system will ignore the bad frame and probably just use the good frame from its second channel. The hopping system may or may not lose a frame, depending on how many bits it lost and the amount of foward error correction it has. Some might consider Spektrum to be a more robust solution, but this comes at the expense of higher bandwidth utilization.

Thanks a lot.
Norm S

Flyfast1

My Feedback: (1)

Juan and others,

Some of these issues depend on whether the Futaba system hops on all available channels in the band. This may not be the case, but I do not know exactly how their system works. Many other wireless communications systems that use frequency hopping don't use all the available channels, only a subset of "good" channels. For example, the systems will build a table of "good" channels, i.e., channels that have less than a threshold level of noise, and then select a subset of those channels to use in the hopping scheme. Some wireless communications systems also use a set of non-overlapping channels in the band, which is considerably fewer than all of the channels in the band. In this situation, even with several Futaba systems operating, there would be available channels for Spektrum systems to use.

-Ed

Peter_OZ

My Feedback: (1)

dunno about in the US but down here we are seeing a loty of guys losing planes while using the DX5 & 7. One guy has lost 4 planes and the agent replaced RX and TX several times while trying to help him out.

These are not inexperienced fliers either but guys who know their stuff. On the other hand other users have not had a problem!

I'll sit back and let the technology mature a bit longer I think

Mike Sieniarecki

My Feedback: (3)

Sorry guys, I was in a meeting :-/

Regarding the last several threads: I will do my best to try and answer them here in one post…

The only testing we have done with our systems directly to a Futaba product was at E-fest two weeks ago when the Futaba guys were using their new system. Of course, as expected there were no issues. Without a system to test, it’s hard to tell you we have compared side by side specifically with a Futaba in hand. However, I can tell (and it was stated in a couple posts back) there is an FCC mandate for how the two technologies (FHSS & DSSS) are to co-exist in the same environment. I would have to assume Futaba (a very large and very respectable company) has done their homework. They do have an FCC grant, which tells me they are within the guidelines for this technology.

Back to the GUID business…They will not interfere. Because the amount of information that is sent is so many times faster than what we are used to on 72MHz, and for the short amount of time the hopping happens, not enough information is lost to affect the signal, and once again, the GUID is not read, so the receivers ignores the stray signal altogether.

The bottom line: with the knowledge of FCC mandated regulations on 2.4GHz, if followed by manufacturers, there will be no interference between brands.

Note: these explanations are in basic terms that are relevant to most modelers. If anyone is interested in further techy terms or very detailed electronics information on 2.4GHz, I would suggest checking out some of the websites that explain all of the academic parts of the technology.

Is this helping?

TeePee

My Feedback: (24)

Will the Futaba module work with the Super 8.

Thomas B

My Feedback: (4)

I'd like to ask the Spektrum folks a direct question:

What is the rational behind having the stock tx antennas removed as part of the Spektrum module conversion.

I fly one of the homebrew DX6 modules in my Futaba 9CAP. It has the 2.4 tx antenna mounted on the back side of the module, pointing up.

I did extensive range testing with and without my stock 72 TX antenna in place while testing the DX6 module conversion...it made no difference. I always fly it with the stock 72 tx antenna still in the TX, retracted.

It would make switching back and forth from 2.4 to 72 much easier if the stock 72 antenna removal was not part of the process......