Oberst

Thank you sir! It's funny Dave, but after reading the article in Model Aviation and I quote, " One option for a 2.4 GHz RC user is to change operating frequency to the 72Mhz band."

That's fine and dandy if you are using a 72mhz radio with a 2.4 converter! Even then, you'ld have to rip out the 2.4 reciever and replace it with a 72mhz receiver and put in the TX and RX crystals to make it work. But what about all those who gave up their 72mhz radios for the straight 2.4 radio? I know the answer, they are S^%t out of luck!

This is what happens when the market refuses to give us choice and forces us to move to a new product that has issues. Talking about a monopoly! For those who remember, Spectrum and Futaba Fast both had a trade in deal when the 2.4 was first released. For those who traded in their 72 mhz for the new 2.4 for the additional discount? All I can say is bad move. Now if you see your radio acting up, you can't switch back to 72mhz unless you buy a used radio, or have a extra radio and reciever on hand.

But I'm one of those people who don't just run out and buy something just because it's new. I did it the smart way and when I started seeing and reading about the 2.4 having issues, I bought a few more 72mhz radios just to hold me over until the 2.4 is finally replaced. It's about time the AMA admits there's a problem! That's a good start and only the beginning I hope.

Someone wrote that eventually the 2.4 will be replaced like the 72mhz replaced 32mhz etc. That is very true, however I found a few places still selling the left over 72mhz and I know of many like me who refuse to operate on a 2.4 system and are still using the older equipment. The 2.4GHz however, will be replaced much sooner than it normally would if there was no issue with them to begin with. That's what I was told.

Someone wrote that Spectrum issues are now resolved? That's not a true statement. Both Futaba, Spectrum, Aurora, Airtronics and Hitec has been recorded to have had issues this year.

They are many issues with all of the 2.4 systems that we know about. How many have crashed because of the 2.4GHz that we don't know about? Slowly more and more are focusing on possible issues with their 2.4 radios. Matter in fact, while I write this another person just started a thread that he lawn darted his 50cc airplane in the Crash/Rebuild. He stated his 2.4 Aurora 9 blacked out and gave him nothing but headaches. Another $2,000 gone!

http://www.rcuniverse.com/forum/m_10...m.htm#10780831

Of course we have people already trying to tell andizzle that everything else went wrong other than his radio. Let's give him credit- he may be new but he isn't stupid and knows that his 2.4 acted up.

A new technology introduced into the market automaticly makes the older technology it's replacing obsolete. To me that's a big misnomer.


Pete

Sport_Pilot

That the plane lost control for three seconds, why it did is conjecture.

HighPlains

My Feedback: (1)

Glad I still have a 27 MC tube transmitter and regenerative receiver in case that newfangled superheterodyne doesn't work.

Silent-AV8R

47CFR95.207 makes it clear that while hobby R/C frequencies (also referred to as "channels" by the FCC) are granted permission to operate on specific frequencies were not primary authorization. If you are primary, then you are the one who everyone else has to stop interfering with. If you are not primary, then you are the one who has to deal with the primary authorized users.

Sport_Pilot

I read where he did have the technical knowledge, from experiance. You should have read the full script that Red had posted. He certainly has the experiance to know what is a good frequency to use. I do not see where spread spectrum is challenged, only what frequecies it should be on.

Sport_Pilot

Unless the plane is near eye level you would be able to see the plane over his head, The transmitter is held at or just below chest level so it could be blocked. Some are saying it would not crash the plane. The plane lost control and went into failsafe mode for about three seconds, it did not crash.

Sport_Pilot

That does not seem to say what you assert. To say that it will not interfere with adjacent channels does not in turn say that the adjacent channesl may interfere with ours. For that you need to go to other parts of the regulation.

Silent-AV8R

Totally off topic. Please, go read the entire section. It says exactly what I am saying. Only a PRIMARY user is afforded protection from adjacent channel or other in-band user interference. We are not and thus we are NOT primary. On 2.4 (ISM band) nobody is primary in that section of the band.

To review:

WE are the ones who must stop transmitting if we interfere with other authorized users.
WE are NOT afforded any protection for other authorized users in the band.

I just do not know how much more clear you need to see it.

http://ecfr.gpoaccess.gov/cgi/t/text...95_main_02.tpl

Oberst

However, if you tweek the regenerative with a tweeker, the flux capacitor you should observe about 50 ohm's out of the 27 MC tube improving it to the superheterodyne apparatus. That's of coarse if you buy the thinywatchamacallit regenerative receiver then the olfangletoot rays should hold long as it's grounded to the 27 MC tube transmitter. All the superheterodyne is or a better word for it is a microflux resistor, that capacitates the nuron acids hitting the regenerative receiver that amplifies the regenerative to work as a Raster Superheterodyne.


Pete

378

My Feedback: (4)

I'm just putting this out here: Car guys don't have problems with 2.4ghz. It's unequivocally better than FM and AM for us. We don't have any latency issues, we don't have interference issues, we don't have any bind/link issues, we don't have any range issues, and it means those of us who like stick radios don't have pesky FCC regulations in the way. We also don't have ROAR and IFMAR spazzing out about it, matter of fact they actually recommend using 2.4ghz in competition.


Idunno what the AMA is on but I think they got it from the Crips. I love 2.4ghz, hell I'm even on the dreaded Spektrum. My NTC3 is perfectly fine on Spektrum, DX5e Tx and AR6110e Rx if you're curious, and I've never had any lockouts, glitches or latency issues. I have no qualms about trusting my aircraft to it.

Silent-AV8R

According to all the "theories" 2.4 works very badly on, or near, water. And yet most all boat racers are now on 2.4 and loving it. Go figure.

378

My Feedback: (4)

Hrm.....Next time it rains heavily I'll take my NTC3 out and find out what's what. The Rx is maybe an inch off the ground, in a plastic box that's bolted to a piece of aluminum, the underside of which gets quite wet operating in the rain. If there's anything to that I'll find out.


Most likely though, I'll just be able to powerslide around happily as I do in the dry

Oberst

Car guys and indoor flying the 2.4 works well. Why? That's because car guys and indoor pilots don't operate hundreds of feet away.


Pete

378

My Feedback: (4)

I've run my touring car out far enough to lose track of which end is pointed at me and I still had perfect control over it. I managed to re-orientate myself by softly blipping the throttle while turning full lock and noting which way it moved.


I can still keep track of that out to about 100 yards or so. It was quite a ways out, farther than my old AM set would reliably work.


Edit: It's also worth mentioning the FPV car guys that are driving, quite literally, a mile away from the transmitter. They have to turn back because the camera signal gets weak, they still have a solid 2.4 link with the servos. FM and AM need crazy powerful boosters to do that, 2.4ghz radios do not.

Oberst

No, 2.4 doesn't work submerged. The Thunder Tiger Neptune Sub is a 72mhz.


Pete

Oberst

Sure, but it's not the same distance that we fly our glow/gas planes. We fly at a very, very far distance sometimes. Especially if there are a lot of other pilots flying at the same time and one is trying to land, or if a man walks out in the field, we have to keep our planes at a safe distance. At times I've had my planes only a small spec in the sky.


Pete

378

My Feedback: (4)

check my edit. There's FPV car guys using unmodded 2.4 radios out to a mile.

HighPlains

My Feedback: (1)

It's obvious that most posters on this subject have no RF background.

Oberst

I'm a bit sceptical until I become a witness. Also it should be mentioned that the operator stands higher than the car, the opposite can be said about operating rc aircraft. Big difference.

I tend to agree with that opinion.


Pete

378

My Feedback: (4)

Go onto youtube then. There's plenty of FPV car videos posted where they drive insane distances away with no issue whatsoever.

Silent-AV8R

Fair enough, and yet so few of us operate our models submerged I fail to see this as an issue. My radio melts in a forest fire as well. But that matters very little since I rarely fly in forest fires.

capt1597

i also totally agree with oberst! what he is trying to discuss is dead on! how do i know? had a nice talk with my little brother. he is an electrical engineer at JPL. he is a inter-planetary comunication specialist at JPL (talk about radio control toys). the nice thing is he dose not have any thing to sell and he is "the man" with the tech knowledge. in laymans terms, that are grossly symplified, 2.4, which is also cell phones, has disconect problems, and fm has "stepped on" issuses. if one flys in areas where there are no interference fm wins hands down. all the rest of these arguments seem to fall in the area of "follow the money". personally i still am flying my fm-pcm radios because i have never been shot down where i fly (that falls in the "don't fix what ain't broke" group.

Silent-AV8R

2.4 has proven to work extremely well in what I consider one of the most challenging RC environments. Competition thermal duration/F3J planes. These carbon fiber and fiberglass planes have their electronics jammed into a very tight area and operate at distances that most airplanes and all helis would simply disappear. The planes are now generally 3.5 to 4 meters in span (138" to 160") and we fly them as far away and as high as any RC model will ever be flown. If 2.4 is robust in those circumstances then I feel it is reasonable to assume that it is equally robust at closer distances.

Oberst

They go behind obstacles at a mile distance, all I saw on youtube wasn't a mile but a few hundred feet and no obstacles other than rocks , and all the others did mostly stunts. If you send me the link I'll check it out.

But so far to me comparing RC Cars to RC Airplanes is like comparing apples to oranges.


Pete

Sport_Pilot

It is not off topic. Can you point to the part of the regulation that explains primary or secondary users? Typically broadcast and other commercial users are not asked to turn off their equipment because they will lose money if they do. Not the case with our RC equipment.