rctech2k7

My Feedback: (1)

Those electric conductors around the area like metals, etc. are not considered blocking RF signal although very much they can. The only possibility when this RF when suppressed or discharged by a bigger surface… Although these are very tiny electromagnetic waves but it still can produce a little output not just to dissipate, mostly develop the same RF waves, penetrates, conduct or bounce to any possible directions by these conductive materials and then to the Rx ant. Depending on the nature of the materials but reactance and distance are some of the factors. I believe those 2 ant 90 deg with respect to each other is more than enough to cover the full 2-dimensional area on our front….

MetallicaJunkie

5.8ghz is coming out soon!! gonna get me a module for my 10x[8D]

sidgates

My Feedback: (2)

To answer your question about Weatronic. The receiver has two whiskers 7 1/2 in long on the Micro series. The last 1 1/8" is the active area. There are two complete receivers in the case so it is like have a receiver and a remote where the two active antennas can separated by 15" max. Both receivers hop frequency approx. 100 times a second.

There are two complete transmitter RF sections in the Transmitter module. The receiver telemetry transmits back receiver battery voltage, receiver temperature, and RF field strength. The transmitter records this data on an Micro SD memory card. The log file on the memory card has an entry each second for the receiver data plus transmitter voltage and the control position of each servo at that point in time.

I have ground range checked the Weatronic Micro to 2700ft. (as far as I could get line of site at the Arvada,Co. flying field). I passed under a HIGH VOLTAGE power line during my range check and the log file showed reduced RF strength when I was near the power line but I still had total control.

hyperdyne

My Feedback: (6)

If this was a case of multipath or fading loss then this corroborates Futaba's single antenna switching circuit is suboptimal, as would be expected on paper.

rambler53

My Feedback: (494)

Some valuable lessons come at great expense.
What is the proven form of RC modulation for decades? 72Mhz. Aurora 9 just came out with a 72mhz radio. So tempted. No one is on my channel anymore, nothing to hop around. I'm using a 4 channel FM Futaba conquest with servo reversing (fancy), and OS SF engines.
No crashes, weekend after weekend. Cost me $25 for the radio and receiver. I paid more for the receiver battery!
I didn't go to Nall either, because I'm not an AMA member.

Four Stroker

To replace or change FASST antennas you need the proper tool:

http://www.digikey.com/scripts/DkSea...?name=H9159-ND

I have been using long antenna since day one - homemade. This micro-coax has about 4 dB per meter drop. I added 240 mm or about 1 dB. As Phil Kraft said long ago, you need about 40 dB link margin. So 1 dB ain't squat. The U.FL connectors are fragile and can be easily trashed if you pull and tug on the coax. That's why you need the tool to replace or change the antennas.

Finally, if you use the standard antennas and stick them next to metal or bundle them up with servo wires, RANGE WILL BE REDUCED. People seem to have forgotten what an antenna is all about. If you duct tape satelllites onto your battery packs, you won't get much range either. I cringe whenever I see most 2.4 GHz installations of any brand.

readyturn

My Feedback: (9)

Would you please expand on this statement... seems to be all inclusive.

Thanks

g6rcteam

i talked with david yesterday on facebook he sent the metalized plating with futaba for testing he will keep us updated on what they find

g6rcteam

this is the first time ive ever heard that cell phones and blue tooth crap causis interferance i think we need to prove that befor we start spreading rumers i was an electronic salesman and the fcc numbers on those items didnt have any referance to 2.4 i think what you might be thinking about is home phones wich run on a low wave setting is there anybody out on the net that might give us all a lesson on phones

siclick33

Is there any proof that there were range problems? It would be interesting to know if anyone didn't fly due to problems experienced on the ground. If there were range problems, was it anything to do with installation? Without knowing, it is impossible to say whether satellite RXs would have helped or not.

I'm not sure how the flight lines are arranged and how the frequency control works but assuming the site only allows one of each of the 72mhz channels out at once then that is a max of 50 TXs (pre 2.4). Bearing in mind at any one time there might be people returning/collecting their channel the number of transmitter turned on would be lower. If the reports are correct that talk about 100+ 2.4 TXs on at once then it is a big jump. It's great to say 'let's go back to 72 but that would reduce the numbers flying at once. Would having a limit of 50 2.4 TXs have prevented any issues? I don't the answers but to dismiss 2.4 without knowing (not guessing) the causes of the crashes is, in my opinion, premature.

Doug Cronkhite

My Feedback: (34)

Unless you know the numbers of the various brands of radios in use at Joe Nall, you really can't say the reason is due to people now buying Futaba radios more.

I'm more concerned that there are people jumping on the 'radio lockout' bandwagon, without all the info. It's very easy to decide it was a 2.4g problem when in fact it could have been any number of OTHER things going on.

With the proliferation of 2.4g in the hobby, I think people are losing sight of good practices. There's no way to know how many radios were turned on at any one time at Joe Nall. No way to know how many people in the pits have their radios on doing setup, testing, etc. even though they've stated that radios may only be turned on at a flight station. It was reported that several people were flying foamies and park flyers around their motorhome/camping areas as well. With over 1100 registered pilots, you can see the potential for a problem.

g6rcteam

yeah but we cant go to topgun and compete with a fm set we are forced to go to 2.4 for the big contest and flyins i to have some old fm futabas i love......... 8cap 4exa conquest and a pcm conquest sometimes i stil use these radios in funfly planes or 60 size sport models i have 1000.00 dollars tied up in my 2.4 gear that i got two weeks before topgun only to find out that its no good and all the companys are having problems at big meets so if we changed to 2.4 for safety reasons maybe we need to go back to fm am till they can put out a good prouduct that is SAFE!

VF84sluggo

My Feedback: (55)

I don't know that, just acknowledging the possibility of a statistical probability if it is true, as was suggested by another poster on this thread. I am in no way trying to start a brand war.

It reminds me of deep water survival training. A guy in the class asked about shark repellant. The instructor said not to worry, that 99% of all shark attacks occur in less than 10 feet of water. To which the class wise-guy piped up and said, yes, that's because 99% of all swimmers are in less than 10 feet of water!

Doug Cronkhite

My Feedback: (34)

Nothing is ever going to be 'safe' if your definition is it'll NEVER have a problem. What has made you decide your newly purchased 2.4g equipment is suddenly 'no good' and useless? I've been flying 2.4g for quite awhile now and never had a problem, but I know I'm not immune to issues, I just do whatever I can to reduce the chances.

It seems like there could be an issue at massive events like Joe Nall due to Rf saturation, but for your average contest, it really shouldn't be an issue. Even at Top Gun, how many contestants are there, and how many radios are on at any one time?

VF84sluggo

My Feedback: (55)

Doug - I think the answer to this whole thread boils down to exactly that. Any 2.4g issues at Nall most likely have absolutely nothing to do with Futaba per se.

redbaron1930

While not a jet pilot I am on the other end flying WW1 palnes with plenty of flying wires. It is never a good idea to have a reciever near conductive materials
or to have conductive loops in the airplane no matter what the technology is. Relying on radio technology to cover up installation deficiencies will at somepoint
come back to bite us!

g6rcteam

87 posts of them having problemsat one meetyes i am worried about it ive used 2.4 for years BUT had to upgrade to futaba because dsmx recivers wernt available and a 6 month wait for trans updats so i went back to futaba only to find out that the fast syst will be overcrowded now that the dsmx is out i think theat all the radio companys need to put less into marketing and more into research an development AMA PLEASE LOOK INTO THIS BEFORE SOMEONE GETS HURT! my current radios 8fga dx7 6exa 4exa and some conquest futaba 4ch the problem i see and said was we were forced to go to 2.4 for safety and now we find more problems then ever on 2.4 bottom line we as pilots need to take control and go back to impoundiong trans and less numbers at big meetsbefore something goes wrong one time and thats the end of r.c airplanes we will all be foam fliers at top gun there were at least 100 planes and a possibillty that at one time any number of radios were on due to the working on the planes seting up radios a couple of crashes were blamed on 2.4 and a cell phone but most if not all were pilot error
i also have never had a radio hit on 2.4 or 72mhz in all my years of flying 27 knock on woodgrain

hyperdyne

My Feedback: (6)

Basically if there was more reflective materials than expected, the receiver could of seen increased fading/multipath which can cause rapid signal loss. And because futaba uses a single antenna at any given time. The best of their 2 antennas in the Rx is selected periodically and that one is electrically switched in. The cost function on which antenna to use is based on the correlation triangle "health" from their DSSS despreader (this is all in their patent). Problem is, the despreader is downstream and potentially the problem has gotten worse when the switch is finally determined. And then what if the other antenna is not much better? Signal lock is lost and Rx must do total reacquire. Add in lots of other signals that bring the noise floor up and aquisition (the achilles heel of any DSSS system) takes longer. Things can spiral from there.

You can read the "2.4GHz lockout today" thread, lots of good technical info. Point is, I will take a RAKE receiver any day of the week versus a single antenna-switching algorithm.

Anyway, YMMV.

Doug Cronkhite

My Feedback: (34)

OK.. at Joe Nall.. the subject of this thread.. there were over 1100 pilots with often more than one airplane per registered person, with people flying there for over a week. Top Gun's numbers are very small by comparison. To suddenly worry that your 2.4g radio is 'no good' because of the number of posts in this thread is a bit paranoid IMO. You said yourself you've been flying 2.4 for years, yet this thread and the number of replies in it has you worried?

It's very likely that 2.4 is being blamed unfairly in this situation.

mr_matt

My Feedback: (10)

IMHO this is a good post. And thanks for your service, BTW.

I think it was in late 2003, Bob Wilcox and I built a 2.4 GHz spread spectrum 16 channel radio and flew it successfully. We took it to the AMA to lobby them to approve the use of spread spectrum radios (at the time they only allowed the specific narrow band frequencies)
We used single TX and 4 satellite receivers in the plane, in a digital architecture that (I GUESS) is similar to the new futaba S Bus (just a guess). We had continuous feedback to the TX, in real time, of the RSSI (received signal strength) of each receiver. You could see the RSSI fading as the plane maneuvered and as you moved the transmitter antenna, and not a little bit, the signals were going up and down many dB. You could see when the .40 sized glo motor got in front of one of the antennas. Imagine what a turbine tailpipe does!

After this we built a TX with 2 transmitters. And we were about to start working on 900 MHZ for better signal propagation. We quit about that time as we felt there was not enough Intellectual Property (patents) that could be protected, in other words if we got this thing working, everyone and his brother would be making a radio and the competition would be fierce. We were too small to compete.

Like 2.4 GHz, 900 MHz is one of the Industrial, Scientific, and Medical (ISM) bands. 900 MHz has a bigger aperture (size of the radiating element, the antenna if you will) so metal “things” look smaller to it. And (in part) because it has less bandwidth (OK for us), many of the users of 900 MHz have moved to 2.4 GHz, and now even to 5.8 GHz, so the band is less crowded.

As for design margin (or design limits as you call it), if you look at 72 MHZ operation, with ideal antenna orientation, you might be able to get 1.5 miles of range (just for sake of discussion). So let’s say we typically fly our planes no more than a ¼ mile away from us. That would mean we are only using 1/6 of the potential range, so we have a lot of extra design margin.

I have no analytical way to back this up at my fingertips, but I think in most cases, we are flying at about 75% of a 2.4 GHz radios max range. So we only have 25% margin for poor installation, high noise floor, etc. So the spread spectrum designs have to be more robust.

In my mind, an ideal system would have multiple TX antennas (or actual radios) similar to Weatronics, it would have satellite RXs like spektrum, and it would have FHSS (or a hybrid FHSS/DSSS) like Weatronics, Futaba and maybe others by now.
I have a feeling that Futaba S Bus might eventually get 2 out of 3 of these (depending on how the RXs can be configured) , or maybe a Weatronic if you ran multiple RXs through DPSI “like” power boxes.
And of course it would be on 900 MHz but nobody seems to be looking at that. Or it would be a dual frequency system like ACT makes, one side is 72MHz (or 35 or whatever you use in your country) and the second TX is on 2.4 GHz.

g6rcteam

yes im worried    my point was this problem will get worse as more radios are sold as more dsmx are getting upgraded we will see more and more crashes i just dont like risking someone getting hurt by what i have found to be more then just a good hobby but a lifestyle that we plan our vacations weekends  and  almost any spare time into if it werent for r.c. i would have never flown fullscale never worked for oldrihinebeck aerodrome or worked booths in oshkosh or sun&fun i have grown up around this hobbie it has helped me shape my life and i just hate seeing anything that might jepordize it. alot of kids learn on models then go on to airforce  one of my ex r.c student flies drones another just got accepted to embry riddle        idk what the fix is but im sure that it needs to be addressed by someone that can do the proper testing and fix our ever growing problem i think us posting over and over that there is a problem will help in some ways but not fix the problem at hand  by the way i do love my new 8fga its a really nice system   

g6rcteam

good luck to all who fly 72mhz or 2.4 i hate seeing a plane crash for no good reason all planes have souls    see you at warbirds over the rocks

Sam-E

Hahahaha, the internet knows no bounds, last year at the Nall it was JR, this year its Futaba, I just love the internet!!! Sell your FAST sets boys, where going back to Spektrum!!! hahahahahahaha, so funny!!! Next year theNallAirtronics will fail and the year after that the Nall will be primarily control line!!!

hahahahahahahaha!!!!!!

allmetal plane

My Feedback: (1)

Hi guys!

Would you please allow me to share my experience! I am not intending to bash brand X or Y, I am just sharing my own experience ..I am not the most skillfull pilot but for years I have been designing, building and successfully flying all aluminum airplanes. To build them, I use several alumium thicknesses, steel, chromo molibden which is highly magnetic, I use a lot of AN stainless steel fasteners, n addition to that I use gas engines which generate lots of RF. This kind of contruction create the worst interference enviroment ANY radio systems..
My first experice with aluminum RC airplanes was in back the 80's when we flew at a 9000 ft elevation field a 16 ft, 150 pound Cessna 180 for years . We did not have resitor spark plugs or fancy electronic gadgets at time and yet, we were very successful with that plane. We had a regular EK Logictrol FM system, the receiver, good Nicads and strong servos for that era.
I do my best in keeping the radio installation simple and IMHO, I stay away from aftermarket gagets, regulators and powerboxes (unless it becomes a real need). SO far I had NOT HAVE ANY ISSUE with 2.4 equipment. JR, Futaba and the other good brands, are nowdays, electronic wonders that make life easier.. if kept simple. I have chosen to fly my metal planes with JR DSM2, DSMX Systems which have given me may hours of trouble free flying (being me the poor pilot!)
I believe that regardeess the brand you choose, it is important to keeping radio installation simple and neat with the proper accessories, this will insure good performance.
I also believe that in addition to being exposed to midairs due to crowded skies, the number of radios operatong at the same time, should be limited.
I hope this encourage folks to continue this great hobby!

Flyfalcons

Yeah because there were never any problems using 72mhz at big events.