kochj

Because it is much better to call them "features" rather than "fixes" or "add-ons"

SkidMan

My Feedback: (17)

I was CLEARLY only talking about Spektrum and Futaba.

My list of firsts included in the heading: "Here is an incomplete list of some Spektrum - Futaba leapfrogs."

Ron Stahl

My Feedback: (12)

Chuckk2, since I have just gone through patent training and am listed on a U.S. Patent No: 8,011,620 . I can tell all of you this as fact. There are no international patents. You must file in each and every country for patent protection. U.S. Patents fall under three categories, and some expire in 15 years, mine expires after 20 years as it is a technology patent and not a design patent which is much easier to get. You can get a patent just for a different color scheme on a product and it would be listed as a design patent, just as a different style of lamp would be. All of this said every system we use as modelers is not bullet proof and batteries are still the main fuse of crashes. I lost my BVM Electra at an event when my year old and freshly charged battery failed during the flight, I lost a two meter pattern ship six months later with another battery failure of the same style battery a 2700 five cell and I have been extra cautious about my batteries ever since. I have never like NIMH batteries but have become better educated about how and why they fail.

H5487

I've been on the road for a few days and I'm just now getting back on line. Not too surprisingly, while I was gone, this thread degraded from addressing the OP's question, to downright product bashing. Many of you posted some serious, mature responses but a few others contributed nothing but rectal leakage which did nothing but degrade the thread. This kind of behavior is no different than what I would expect between several arrogant drunks who are adamant that their brand of pickup truck is better than the other drunk's trucks.

OP, did you get your question answered?

Harvey

rmh

Oddly enough - the correct answer is simply ignored.
Spektrum developed the first working -commercially successful rc aircraft 2.4 system.
One of the patented features is the satellite setup.

ALL the systems made by others had to license this (satellite) in order to use it.
Apparantly only JR choose to do so .
Will a system work without it ?
Of course .
So why continue using it?
It has the potential to reduce/eliminate blind spots in reception by having multiple reception locations .
Just that simple.
For the non believers
IF you have an on board signal detector - the various locations will show how reception changes during a flight due to distance/ attitude.

One of the features for all 2.4 radio users is that momentary failures in reception are ignored in the model .

IF these failure pile up -the system stops working till a solid stream of info returns - often this is never noticed by the flyer -
However there is typically NO warning- just a loss of control.
IF reception is the cause - - then it is prudent to consider the best reception arrangement for YOUR particular setup .
Some model due to size and material used get along just fine with one single antenna and at shorter ranges these setups work just fine..
The real issue was is and will be, the misunderstanding 0n type of rx required and correct selection of power and power connections for the radio.

It is demonstrated over and over in these forums , some do not understand how to evaluate power problems vs reception problems
The correct tests for these take some experience - not just a wild guess.

JPMacG

My Feedback: (2)

Thank you rmah. Very well stated. I suspect that you are absolutely correct. Spektrum engineers felt that the satellite receivers would enhance their performance so they used them.

I do wonder why Futaba did not decide to do the same as Spektrum. I do not buy that the patent was so broad that Futaba could not find a way around it. I suspect that the Spektrum patent claims would have to be very narrow in order to be patentable. After all, there is a lot of prior work; diversity reception dates back at least 70 years. I suspect that Futaba could have found a way around Spektrum's patent, for example, Futaba could have had three or four sleeve antennas coming out of their receiver enclosure instead of just, two with three or four receivers inside the box. For some reason they thought it was not necessary. Perhaps they benefitted from Spektrum's experience. After all, Spektrum was the first. Or perhaps Futaba's modulation technique provides better processing gain? I don't know.

I also wonder why 72 MHz systems do bit have momentary lapses because of signal loss during instances of cross-polarization or multipath nulling. I suppose that the link budget for 72 MHz is so robust that any losses will be of very short duration and not noticeable to the user.

rmh

The 72 MHz systems were completely different
Comparisons are misleading
for one - the 2.4 is a broad spectrum type - the 72 is not
Huge difference
Tho later types 72 we use were digital info (PCM) - they basic approach was still the same.
looking at range as an indication of superiority -as some do - is very misleading
The list is extensive.
The fact that spread spectrum allows for hundreds of users to operate at the same time , is a leap that we as modelers can't -and haven't failed to notice.
The frequency control necessary for 72 was a real PITA for most of us.
In a perfect world, there would be no frequency conflicts
2.4 broad spectrum is pretty close to perfect in that respect.
The compromises in using 2.4 are real- proper power and good antenna setups are a must .
Like most, I have had literally zero problems using 2.4 - any brand - as for patents being narrow - - , they must be closely defined in order to protect their use
The whole idea of the patent was to give the originator time to recoup time/money in developing the patent.
Some patents are so important that the government actually decides to make them available to others to produce. - some medicines fall into this group.
The patents I did were novel and new devices which is a different category than application patents - The whole patent field has changed from the original concept.
Money changes everything .

HighPlains

My Feedback: (1)

The nature of patent law has changed quite a bit over the years. While on one hand they protect the intellectual property of the inventor or the assignee, they are also meant to teach - thus they foster further invention along the same line. In more recent times, it has gotten much easier to get a patent. They don't really reject very much anymore, because if one company thinks another has infringed, then they go to court where it gets decided. So many large corporations end up with as many patents as possible, so that they can trade with competitors since both companies would otherwise get killed by lawyer fees. If the patent turns out to be of little value, it may be abandoned, since over the 20 life the owner of the patent has to pay fees three or four times. Of the 7 patents that I am on, only a couple went international. Since they were high tech in nature, you only have to file in a handful of countries, and pretty much forget about the mud-brick part of the world.

The cool thing about patents is they last forever, and anytime a new patent is filed and granted, if it expands on your patent then your name ends up on the new patent as prior art. My name was on about 130 patents the last time I looked.

rmh

discussion of patents could fill a library (and does).

H5487

Why is it filling a thread about Futaba's vs Spectrum's receiver layout?

rmh

EASY ANSWER- The system Spektrum uses is patented - Futaba could not use it
then the comments on patents kinda followed .

H5487

But it's not answering the OP's question.

I'm not getting on y'all. I've been guilty of hijacking a thread or two myself. I'm just trying to steer this one back to the original subject.

Harvey

rmh

I thot the question was answered.
did you want to discuss the merits of each?
that was not the original question.

JPMacG

My Feedback: (2)

I think the OP had his question answered several times in the first 5 pages of this thread. He will have to decide which answer to believe, if any.

I don't see the patent discussion as irrelevant or hijacking the thread. It is an entirely plausible explanation for why Futaba does not use satellite receivers. I am skeptical of that explanation and stated my reasons. RMH disagreed with me and stated why.

Ozmodeller

+1 I agree, not that I understand nor do I think that I will be submitting a US patent anytime soon, this thread has so far almost restored my faith in my fellow modellers in that they are capable of rational thought processes without lowering the discussion to name calling and any one particular brand defence, well done.

H5487

Then I stand corrected.

Carry on.

Harvey

H5487

Actually, the opposite has been quite prevalent in a couple places in this thread with some folks adamantly insisting that they hate some brands.

Harvey

rmh

You have to expect those comments -
It is a reaction to issues they can't understand .

Ozmodeller

True, but for the most part most posters have been quite restrained, you will always get those that do not or will not try to understand what is being explained to them, I for one have appreciated the majority of the responses, in my case its a case of your never to old to learn something.

Maxam

My Feedback: (62)

I would like to demonstrate why multiple receivers has been beneficial. I fly several planes with large radial engines including a moki 215, saito 325 and Seidel/UMS 9-90. I have used the DSM2 system with no problems with the Powersafe 9 channel unit with 4 receivers placed around the airframe. I had great success. The data logger is a fine tool for evaluating and thus optimizing receiver placement. I read many negative comments about spectrum/JR performance. I thought I would try the Futaba system. I bought the neat 8 channel system with the classy looking transmitter. Binding was fast and all seemed well. The short sticks and smallish transmitter fit my small hands. Virtually every time the plane was coming at me, the signal was lost with the obvious momentary loss of control. I tried different orientations of the antennas but still had a consistent loss of control when the engines were between the receiver and the transmitter. I was not pleased. In any other orientation the radio functioned well. I now have the DSMX systems with multiple receivers and never have had any holds or frame losses. Spectrum states up to 100 fades/flight on each receiver is just acceptable and 20 frame losses. I rarely have more than 25 fades/ receiver so I have a solid link at all times on all receivers. Notice the new JR DMSS system still uses up to three receivers and so does Jeti. I recall talking to Jeti at Toledo and he stated that yes multiple satelites is wise. -Tom

chuckk2

When there are problems - - -
In general, the antenna(s) locations (relative to noise generators and metal in general) may be involved.
Since ignition systems and so forth generate noise, they can reduce RX sensitivity, or if you wish, general performance.
Frequency diversity can help, as can space diversity (antenna placement)
Designing an RX with high sensitivity, selectivity, and noise rejection is no easy feat, particularly at Ghz frequencies.
Miniaturization and cost of components add even more design problems.
And, if that isn't enough, variation in component behavior from one to another at Ghz frequencies is a factor.

I'd like to mention something we got into about 1990, before RC at Ghz frequencies really go going.
At that time, I was assigned by contract to a USAF/Vendor combined support, test. and development effort.

Some of the AF fighter pilots were getting more speeding tickets than they liked.
"Radar Detectors" were not as effective as desired,
Since we had a microwave lab, they asked us to look at various radar detectors, and see if there was any relationship
between them and tickets.

When all was said and done,
Price was not a major player when it came to sensitivity.
One of the less expensive units was more sensitive than several at four times the price.
False alarms were a different matter. The false alarm rate was a bit lower on the more expensive units.
Within samples of the same make and model, there were extreme variations in sensitivity.

I suspect that certain RF components, such as detector diodes and mixers were the cause of the variations.

Pure conjecture, based upon past experience, leads me to believe that the cost and complexity of doing the selection testing required of components and the final
RX units is also a factor when it comes to RC RX units.

"Digital Signal Processing" is a factor as well, and it's not as cut and dried as some think.

HoundDog

My Feedback: (49)

Don't have any of that crap with my Futaba Caps9 and a Synthesized Module and Receiver. on PCM.
Nor have I ever had a glitch with a HITEC RCD AURORA 9 Moduel or any of my AURORA 9 Radios.
Seen a lot of Spectrum's CRASH for no apparent reason ... Yet there many guys Using DSM2 in high priced Jets and Models an nothing has happened to them so GO FIGURE .... Only time will tell. On the other hand if DSM2 was OK why would Spectrum have gone to a (HOPPING) DSMX system. Why do people buy a Ford, Chevy or a Mercedes? It's all what they feel comfortable with and NO ONE wants to think what they have laid out their hard earned cash for isn't as good or better than the next guy. It's just Human nature.

LesUyeda

" Why do people buy a Ford, Chevy or a Mercedes?"

Ford or Chevy because they can't afford a Mercedes. Me, I drive an OLD Chevy S-10."-)))))))))))))))

Les

rmh

Seen a lot of Spectrum's CRASH for no apparent reason
Which means you don't know the reason for the crash
equipment does not stop working just for the fun of it
If you don't know why the system stopped you should not criticize- best to find out why the failure occurred.
Last failures I saw - were not Spektrum they were on very expensive Futabas
However - I am quite certian the failure was from a voltage reg on rx packs
The earlier holds on these systems,were due to not getting rx signals- the antennas were relocated and it appeared all was good - BUT the same linear regs were still used -these are heat sensitive. For the record I have used all sizes of the Spektrum tx/rx systems since the very first ones were available - - no shutdowns -except for BEC failure- two of those .

HighPlains

My Feedback: (1)

It would great to see a cogent discussion on these various systems by people that have actually studied and worked in communication theory, RF design, and EM field theory. Otherwise most posts are just noise.