KCFlyBoy

My Feedback: (12)

Does anybody know if Futaba makes a synthesizer module for the 7U, 8U, or 9C? I know they make one for the 9Z but it does not work with the afore mentioned radios. I know some people use a Hitec module but I am not excited about doing that. Thanks CB

Ross Kean

"Not at this time" seems to be the best answer I (or anyone else) has been able to get out of anyone at Futaba. As I understand it, this is a product for possible future consideration. As far as I'm concerned the frequency synthesizer module (or lack thereof) for the 9CAF/9CAP is the only reason that anyone might consider buying anything else in this price range.

Futaba is really missing the boat here. I can't imagine that it is too technically complex or that there might be concerns that it wouldn't be safe. Modern electronics are too good for that.

BTW, both Hitec and Futaba will tell you that the Spectra module from Hitec is not legal for use in a Futaba radio.

Ross

KCFlyBoy

My Feedback: (12)

I know it is not legal and that is the major reason I am not excited about using a spectra module. Thanks for the reply.

fenderjw

My Feedback: (83)

I havent checked their web pages recently, but "Not Legal" is not how I remember it. "Not reccomended" was the verbage that I remember. BUT!!!! I have two spectra modules. One in a 9C and one in an 8U. They both work flawlessly! Hitec really has a winner here. They may not "Oficially" support the spectra's use in Futaba gear, but why else would they make a module that snaps in perfectly, as if it were "Made" for the Futaba radios?

BTW, I had our safety guy check my radios using a frequency analyzer with the spectras installed. With the spectra I was within 1 khz of dead center on chans 15, 28, 40, and 57. I have two Futaba modules (28,40) that originally came with the Futaba radios and I had him check those as well. The Futaba modules were 1, and 3 khz off respectively.


Why would swapping the modules be "Not legal"? I can change between modules (Futaba to Futaba) legally (according to the FCC), so why not between module manufacturers?

Thanks
Jim

KCFlyBoy

My Feedback: (12)

I have to agree but it comes down to liability Futaba will not take liability because we are buying a Hitce product. Will sell it to us but won't certify it because they did not sell the transmitter. It is a catch 22. I would like to see Futaba step up to the plate It would be a hit!

snsmith

My Feedback: (5)

If memory serves, I recall from Tower's web page that there was a synthesized modules that could work in an 8U, but Tower's site is down at the moment (grrr)...I'll see if I can find it later to see if my memory is failing (probably).

DavidH

Why would swapping the modules be "Not legal"? I can change between modules (Futaba to Futaba) legally (according to the FCC), so why not between module manufacturers?

All Brands of radios are type accepted by the FCC with the OEM modules. So by using another brand of module in a radio other than what it was type accepted for is illegal according to the FCC.
Also if you have an accident with another brand module in the radio than the one it was designed for, the AMA coverage is null and void.

David

KCFlyBoy

My Feedback: (12)

I also use Hitec receivers with my Futaba radio but at this point and time there is no legal way to do it with a 7U, 8U or 9C. snsmith
I checked with Tower they have a module it is an TK-FSS but it is for the 9z only. So if we want to be legal we have to swap modules.

fenderjw

My Feedback: (83)

Quote from DavidH:
"All Brands of radios are type accepted by the FCC with the OEM modules. So by using another brand of module in a radio other than what it was type accepted for is illegal according to the FCC...........AMA coverage is null and void"

Thanks for the thoughts.
I have not seen this (in writing) for myself. Do you have some sort of reference that I might look at to confirm this. Everything I read relates to the sensitivity of the RF deck itself and I find nothing related to the modules and/or swapping them. Also, there is nothing available from the AMA that I can lay my hands on from tha AMA that supports your statements.


Thanks
Jim

thomasb

EVERYTHING USA users need to know about the operation of a R/C transmitter is outlined in the FCC part 95 Sub C document. It is available at the FCC web site.

I suggest that at least the club safety officer read and understand this document (see sections 95.201 thru 95.225, 95.623 thru 95.673). Frankly, all R/C'ers should spend the hour it takes to read these basic R/C spectrum rules.

FCC Part 95 rules specific to this situation:
95.645 (b) An R/C transmitter which incorporates plug-in frequency determining modules which are changed by the user must be certificated with the modules. Each module must contain all of the frequency determining circuitry including the oscillator. Plug-in crystals are not considered modules and must not be accessible to the user.

Since Futaba has not registered the Hitec module for use with their transmitters, the use of it on a Futaba product violates the FCC standards. I am not the FCC police -- do not blame me on this one.

Also, I heard that the Spectra module experiences a slight shift in the FSK signal when it is used on a Futaba Tx. Not so far as to prevent it from working, but it still should be a concern. I wish I saved the link to the details to this, but I cannot find it (dang).

DrV

My Feedback: (2)

Here are posts directly from AnnMarie Cross (Futaba rep), Mike from Hitec and Futaba's' web site regarding the subject.



[1] There are no synthesized modules for any Futaba radios excxept the 9Z.

Please do NOT use the Hitec synth module in your 8U. This is against FCC regulation and doing so voids your AMA coverage and risks your clubs coverage as well in the event of an accident. For more info you can send an email to

[email protected] with test in the subject and

Can I use a hitec spectra module in my futaba radio

in the body of hte message. Our auto system will provide you an immediate response with details.

__________________
Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com



[2] No, the 9Z uses sofwtare to select the frequency of the module, and so it is not compatible with an 8U, 9C, etc.

FYI -- before it comes up or gets confused -- the Hitec spectra module WILL FIT in an 8U, 9C, etc; however, per the AMA, FCC, Hitec and Futaba, the spectra module is not certified with any Futaba radio and therefore is not legal IN THE US (and may not be in other countries) for use in any Futaba radios.


__________________
Sincerely,
Mrs. AnnMarie Cross
Senior Manager, Proprietary Services and Support
Great Planes Model Distributors
[email protected]
www.greatplanes.com
www.bestrc.com


[3] The Spectra module is being used successfully in the older 7 and 8U series radios but be aware that Futaba has changed something in the 9C and it does not transmit directly on channel so it should not be used.

As for getting it type accepted by the FCC... I really don't want to get into the logistics of this. Just take my word that it will never happen for many reasons.

Mike.


[4] "THIS IS DIRECTLY FROM FUTABA'S WEB STIE FAQ FOR THE 9C"


I am thinking of purchasing an aftermarket Tx module for my module radio. Is this okay to do? Does this affect my warranty?


There are many aftermarket items that fit specific needs and are terrific products to use. Unfortunately, the use of a non-stock Tx module in Futaba modular radios (current systems include 8U series, 9Z series, 3PJ series) is not one of these circumstances.

Based upon FCC regulation 95.645(b), and the advice of our lawyers and the AMA who have analyzed and discussed this issue with the FCC, we must indicate that we believe that any non-Futaba module to be against FCC regulation to use in a Futaba transmitter.

As such, we cannot support this type of use in any manner or we would be violating FCC regulation as well. Therefore we cannot service a radio which is using any after-market Tx module, and its use voids the radio's warranty. Please also note that making modifications to your radio system may void your insurance coverage, so we strongly recommend against doing so.

dirtybird

My Feedback: (5)

"BTW, I had our safety guy check my radios using a frequency analyzer with the spectras installed. With the spectra I was within 1 khz of dead center on chans 15, 28, 40, and 57. I have two Futaba modules (28,40) that originally came with the Futaba radios and I had him check those as well. The Futaba modules were 1, and 3 khz off respectively."

The center frequency may be OK but what about harmonics and sidebands? Thats what causes trouble with other channels.

This is a perfect example of those that don't understand what they are doing should not be giving advise to others.

fenderjw

My Feedback: (83)

Thanks sir. I had no idea that I was so ignorant. I am so grateful that a person of such obvious and irrepressible intelligence such as yourself would come to my rescue!

What makes you think that the side bands and harmonics were not checked? An assumption on your part? How rare in this forum! The particulars were not included in the post because they were not relevant. Please kindly keep your asinine assumptions and snobbish comments to yourself.



Thanks
Jim

dirtybird

My Feedback: (5)

I assumed you did not checked the sidebands and harmonics generated because you did not mention them.
I assume the the frequency generator is a VCO where the frequency deviation is controlled by the modulation level. I would also assume that this is tightly controlled within the module. This has be carefully checked by observing the sidebands generated. I am just guessing here as I don't have schematics for the modules. However, you don't either.
If you have checked these and find them within the specfications required by the FAA submit your data to them for approval. You will most probably have to submit certifications for your instruments along with your data.
After you obtain your certification, you will be able to legally operate your radio wth the spectrum module.
However, you will still not be able to legally recommend this combination to others. For that you will need type approval and a promise from Futaba and Hitec that they will not change the design.
Until you do that I will continue to make snide remarks.
I have a vested interest in this as I don't want someone with a cobbled up radio shooting down my $3000 airplane because he read on the internet that someone tested it and found it was OK.

Capgains

My Feedback: (4)

Hey!!! Lets's put it to the acid test.

The Spectra module is no new kid on the block product. And I have seen posts of people using them back to the Futaba Super 7.

Has anyone ever been shot down by the dirty operations of a properly working Spectra module? Seriously, post your story ,

Rules : Someone turning on to the same frequency by accident doesn't count. We can do that with crystals just as well. Wide bands don't count either, only occurrences where the models involved were operating on separate narrow band frequencies, and a Spectra was deemed to have crossed into someone else's signal.

I'm not trying to try to stir the pot, and I can surely see strength on both sides, but all I have seen is people saying it works great, theories of liability problems, interpretations of FCC rules, and politics of marketing radio equipment. Until the rubber hits the road and there is an actual case where a plane was lost etc. this argument is like the story of the kid in a nearby town that ate the pop-rocks, and drank a soda, and his stomach exploded. Nobody knows who it was, but everyone has heard of it and yet........... it never happened.

Dan Gellner

RCPilot100

My Feedback: (4)

Not that many years back you could buy a Heathkit and put your own radio together. It was a good way to learn electronics assembly, but it didn't give you the theory needed to design, experiment, test and redesign elctronics.

Today, major manufacturers hire the talent needed to put together hi-tech equipment like our radios TXs and RXs. While I am an Engineer and understand Electronics, I know I don't know enough about what is out there now a days to second guess the people who originally designed and tested their stuff.

In this case we have people swapping modules between systems because it fits and anecdotal evidence says it works. On the other hand, you have the Mfgs saying don't do it. Like dirtybird say, I dont' want to lose one of my planes because I happen to be the one that finds out it doesn't work just like the experts say it won't. I lost a Sukhoi last year - no one stepped forward to say they turned on in the pits and shot me down - or was it someone with a Hitec synthesis frequency module in a Futaba radio? I don't know the answer to that question and probably never will. All I know is that it cost me @ $1,000.00 - not $3,500.00 because it was my 72" Sukhoi, not my 104" Extra.

Dan

KB9STD

My Feedback: (1)

OK....Now that we have the "experts" on hand, I have a couple questions I'd like answered!! 1. How do you check the "side bands" of a transmitter using FM modulation? ( Technically it is "Frequency shift keying" which like true FM doesn't produce "side bands") 2. If the FCC requirement for "Narrow band" transmitters is "Side Bands down 55 db at +/- 20 khz" (read part 95 of the FCC regulations) .How can an "FM" transmitter Not be "NarrowBand", regardless of the date of manufacture(I'm not talking about "Gold Stickered"(which was never required by anyone, and the program expired 2-3 years ago anyway)??

thomasb

Until one of the "experts" joins in, I will share my thoughts.

Well, there is no specifically defined "side band test." The typical 72Mhz bench test/calibration starts by verifying that the FSK deviation is sufficiently narrow using a freq counter (or spectrum analyzer) and manually manipulating the modulation input signal. This determines the occupied "bandwidth" of the modulated carrier and it must meet the radio makers specs, which traditionally are much tighter than the FCC rules dictate. Then the Tx is placed on a network analyzer and the signal is checked for harmonics (55dB+ below carrier) over a large freq span. Spectral components in the 90 Mhz and 144Mhz areas are especially scrutinized.

Prior to the narrow band rules, the bandwidth allocations were MUCH wider. The acceptable FSK deviation could be more exaggerated, the carrier's center frequency was allowed more tolerance, and Tx performance over ALL operating temperatures and battery voltages was more lenient. The new "narrow band" requirements required additional attention to these little details.

And don't forget, the narrowband rules indirectly impacted the Rx too. Perhaps more than they affected the Tx.

Joe B.

My Feedback: (1)

I'm not loaded so I'll refrain from hiring a slew of lawyers to make my point... BUT...

This is akin to saying my CB RADIO can only be used with a certain brand microphone. The Tx module system is designed and intended to keep ALL the necessary transmitting equiptment on one board, as per FCC's regulations on user adjustable frequencies. This is the part that is FCC REGULATED. Agreed, swapping a FUTABA crystal into a HITEC module WOULD be violating the FCC regulation but as long as the MODULE (the part that TRANSMITS) is intact then no harm, no foul. The transmitter case (the gimbals/computer) is to the module as the microphone is to the CB - just the device that converts the user inputs into something the TRANSMITTER can understand and the TRANSMITTER is the Rf module. Even if the two are not compatable and transmits unusable junk, it will transmit that junk only on the specified frequency and as far as I know the FCC doesn't regulate WHAT we send with regards to RC transmitters, but how it's sent.

Your warranty is a completely different issue.

KB9STD

My Feedback: (1)

Wait a minute!!! The Encoder(the "gimbals and computer") provide the signal which causes the frequency to shift (in an "FM" transmitter).If that signal is not at the voltage level the rf deck is designed for, it can and will change the center frequency and the bandwidth of the output.As for using a different Mike with a CB, if you were to us an amplified mike it could well cause the rf output to "splatter" onto unintended frequencies( Did you ever hear of a CB'er "Bleeding over"?).That CB is an AM transmitter,just like AM RC radios. And the "splatter" (read "Bleedover") caused by a modulation signal stronger than what the "RF circuits" were adjusted to is exactly what the "Narrow Band" regulations are supposed to avoid (shooting Down a flier on an adjacent channel).
The more I think about this issue( I started out thinking it was not much to worry about) the more it seems that it can't work without being adjusted to the transmitter.
On the other hand, FMA sells an rf deck that they reccomend for use in "existing transmitters". Check it out at https://www.fmadirect.com/site/fma.htm?body=Store
I have dealt with Fred Marks for several years, and his opinion is the one I seek when dealing with RC issues(He was a leading member of the AMA frequency, and helped develope the "Narrow Band" requirement). I have no doubt that Fred knows the issues as well as anyone.And I will tell You that, He designed the "ACE Silver Seven" transmitter he mentions(and the MicroPro also used the same rf deck), But I don't see how he gets by selling the rf deck seperate from the crystal. That fact would seem to have a bearing on the issue of swaping transmitter crystals(although not the legal and liability aspect).
I'll try asking Fred about that point, and post any results.