fremontb

Does anyone know if the Hitec 4400 Spectra Module will work on the futaba 9C Radios? It seems I read a post that some one was using one in a 9C.

tande

My Feedback: (48)

It will work---not legal---but it will work

rjmdubois

I've been using for two years without problem. By the way, were I live is not illegal to use it.

strato911

True, the FCC regulations only apply to the USA. However, the originator of this thread (fremontb) lives in the US, where the FCC forbids the use of a Spectra module in anything other than Hitec equipment.

Zevang

I've heard also that this Spectra Module work on Futaba 8U transmitter. is that true?

Zevang

az_ron

My Feedback: (2)

True, the FCC regulations only apply to the USA.

Just amazingly stupid isn't it... The rules that is...
Like it would work any differently in a Futaba than a Hitec...
The governing bodies in this country are truly amazing... they'll regulate and rule
the hell out of something that makes NO difference, and something of utmost importance
gets overlooked... Sorry, just a quick little VENT!!

Ron

rjmdubois

If I understood fremontb's question was if it works, not if is legal.

rhd-RCU

My Feedback: (36)

It also works in the 8U.

tadawson

The issue is that is may NOT work the same in a Futaba vs. Hitec. Typically, the deviation (how "wide" the signal is, with regard to adjacent channel interference) is determined by the amplitude of the signal going into the transmitter, or the module in this case. As such, there is no guarantee that the signal level is the same into the module from a Futaba vs. a Hitec transmitter will be the same. This is part of what type acceptance by the FCC is about. If acceptance is sought, then a given configuration (radio set and module) are tested together to ensure that the levels ARE compatible. Also, due to type acceptance, a mfg. cannot change levels and such in a given radio without having to resubmit it for acceptance, so if it gets certified once, it is extremely unlikely that anything will change. Having said this, I am not saying that Hitec and Futaba are necessarily different in signal levels, just not formally tested, and POTENTIALLY
different, and as such the FCC rules take exception. Either Futaba or Hitec could submit for the appropriate certification on this at will, but then "Not invented by me" attitues and such start to come into play, and we, as consumers, inevitably lose.

- Tim

mr_matt

My Feedback: (10)

Great post, I think the other signal characteristics (like rise time of the pulses) can affect teh final spectral purity of the output as well.

But discussing this here is like politics.

strato911

I realize that - and his answer had already been obtained.

My post was meant to INFORM that although it works, it isn't legal in the US.

rjmdubois

I am not a certified FCC/AMA/XXX/YYY tester, just a humble electronic engineer, but I have two evidences:

. We do have a frequency scanner at our club and a few months ago we did an interference test with 4 spectras in two 8U and tree 9C and in any case the spread interference was comparable to the original Futaba module.

. I've been flying at 72.110 with the spectra on a 9C for over two years. A very good colleague uses 72.090, with spectra on a 8U and we never had any noticeable interference. We both fly 33% gassers.

I've been loyal to Futaba for more than 10 years, but a few years ago I stop to buy Futaba servos. My newest two receivers are Hitec (I still Use Futaba's PCM), and now I am seriuously considering going to Multiplex TX. I think futaba is very good quality, but they are frozen in time. Despite the wonderful support (best in class), the product line is usually outdated and expensive.

I'm sure Futaba has the technology to produce a clone of the Spectra Module -- actually is on their 2004 brochure. Maybe is just more profitable to keep selling Crystal Modules and foment the idea that one will burn in hell if use competitors solutions.

dirtybird

My Feedback: (5)

All humble electronic engineers should know that a frequency scanner will not do it. You need a spectrum analyzer and it must be a good one. Even so you can only say that the combination of units you tested passed the test. You cannot say every combination of unit will pass simply because you have no control over the configuration of the units.

rjmdubois

That's why I said I have two EVIDENCES.

By the way, do you believe that ALL Futaba's radio are deeply tested before shipping? I guess not, because I have already got servos poorly soldered, and a Friend of mine just got a 6EAX with channel 1 and 3 swapped -- I'm not talking about mode 1 and 2, I'm talking about wrong wiring. It just happens, and I am the first to recognize that Futaba has a world class quality.

Every industrial product standards are done by sampling - you don't crash test every cars just to guarantee it is safe. I may agree with you that we don't have a sampling wide enough to ATTEST there's no interference. That's why I used EVIDENCE.

dirtybird

My Feedback: (5)

Evidence #2 only says it will work for you and the two units you have. You need to go back to school and take a course in statistics.
Futabas are well tested but not with the Spectra module.
You don't need to crash the unit in the testing. Thats the purpose of the spectrum analyzer. It tells you if it is working without crashing it. And more importantly it tells you that you won't crash someone else.

rjmdubois

Maybe you just need to go back to school and get some basic English. I'll make it easier for you. From Webster:

EVIDENCE:
Main Entry: 1ev·i·dence
Pronunciation: 'e-v&-d&n(t)s, -v&-"den(t)s
Function: noun
1 a : an outward sign : INDICATION b : something that furnishes proof : TESTIMONY; specifically : something legally submitted to a tribunal to ascertain the truth of a matter

Now try reading my previous post again. If you have difficulties to understand, I can spell it in Spanish, French, Portuguese or Italian.

Waco Driver

Dirtybird

A couple of years back we had a discussion on RCO about the Spectra/Futaba 8U combination. To refresh, I stated that our club had carried out a spectrum analyzer check on 60 plus transmitters belonging to our club members in order to determine if they were within the AMA/FCC guidelines of frequency deviation and narrowband requirements. The tests were carried out by our club president who has a Phd in Electrical Engineering using an HP spectrum analyzer worth I was told $25,000. One of the results was that my Spectra/8U had the cleanest output of all transmitters tested.

In your reply I believe you stated words to the effect that a simple SA test proved very little with respect to the possibility of my T/X interfering with other models. You did not define what you would have considered a valid test.

In view of your above quotes, have you changed your mind ?

I am quite aware of the AMA's position as well as those of Futaba/Hitec on this subject.

dirtybird

My Feedback: (5)

OK I will agree that the 60 or so transmitters you tested are probably safe to use. At least under the ambient conditions you used.
I believe if you would check with the FAA you will get what is considered a valid test. Until you get that and perform your tests according to those specifications I will not accept your data. I will need a certification signed by your testers and a guarantee that Futaba and Hitec will not change their configuration.

tadawson

Please be aware that if either Futaba or Hitec change their specification, they void their OWN type acceptance and have to recertify, and the result would be a different product, with a different list of compatible parts. As such, let's face it, it ain't likely to happen any time soon. New models will come out, but existing ones won't likely change. Regarding the spectrum tests, the FCC regs. are very specific in the standards of spurious emissions, frequency control, deviation, etc. and if the unit shows to meet these specs, then it could be certified. If it meets these specs, then is should be safe to use, since radio gear does not magically work better with sticker with an FCC number on it affixed. Having said that, even though it may be perfect on the analyzer, and therefore in real life, it is still illegal without the type acceptance.

- Tim

mab0852

Fact is every Tx/Module combination, same brand or not, will vary in both width and strength. We had an incident this weekend where a guy with an 8U on dedicated module (channel 52) that had just come back from being tuned was crossing over onto 53 and caused a plane to crash into the pit area. The guy on 53 immediately asked if someone had turned on 53 and there was no response. When we retrieved what was left of the plane, we plugged the battery back in and the servos were obviously being manipulated by another radio. Fortunately, someone had a signal scanner and we were able to see when the channel went clean to figure out what had happened. Moral of the story is that even FCC approved, dedicated module systems can be a crap shoot. Without a full time spectrum analyzer (too expensive and impracticle), we all take a chance every time we go up or turn on a radio. Note: I'm getting one of those scanners, $140 = Cheap insurance!

dirtybird

My Feedback: (5)

It may not be likely to happen but it can and does happen and you will have no notification. An FCC certification sticker does not magically make it work better but it provides some assurance that it will work to the specifications. As you say it is illegal without it.

tadawson

I would agree that the type certification will provide some insurance that the DESIGN of the system will work to specification IF it is correctly build, and then only when new. Failures, drifting, etc. are not in any way affected by type certification, and as such, the certified and non-certified stuff, assuming both work to spec when new, are equally likely to drift or fail thereafter. Once again, I am ignoring the legal issue in this post, and focusing purely on the technical issues. Being a HAM operator, I have no problems or concerns whatsoever with others on 50MHz changing crystals, etc. the issue is mostly legal, not technical on any band . . . .

- Tim