FlyingGiants Exclusive! Introducing The Futaba 12FG, Modules & More!

[DR10044]

Just curious, where do we fly our planes that line of site is an issue? During range checks I have put objects such as metal buildings between my transmitter and plane and could not get the signal to drop. In practice, I will never do this while flying!

[Hammbone]

	Quote: Originally Posted by DR10044
	Just curious, where do we fly our planes that line of site is an issue? During range checks I have put objects such as metal buildings between my transmitter and plane and could not get the signal to drop. In practice, I will never do this while flying!

Does your engine ever get between your tx and your rx? Do any of your planes have carbon fiber on them? If they do, would the carbon fiber sometimes get between your tx and your rx? Do your servos sometimes get between your tx and your rx? Does metal or carbon fiber landing gear ever get between your tx and your rx?

The manufacturer has said that this may be a problem. I didn't say this, the manufacturer did.

Happy flying.

Jim

[toprudder]

Well, any signal has a problem going "through" something. It is just that the wavelengths involved make the size of the objects necessary to attenuate the signal different for 72mhz and 2.4ghz. 72mhz is line-of-sight as well, when you get down to it.

Radio waves will also bend around objects to some extent. They also reflect. Reflections can cause a signal to be cancelled out, when a reflected signal arrives 180 degrees out of phase with the incident signal.

This is why there are two antennas on the different receivers, and why the Spektrum systems lock onto two frequencies. Mount them according to the directions and you should not have a problem.

The reboot issue has nothing to do with 2.4ghz, it has to do with the way the Spektrum receiver boots up and acquires the signal. A momentary dropout in the voltage causes this, and careful attention to the voltage supply can mitigate this problem. This is not as much of an issue with the Futaba FASST system, the voltage must drop much lower and also takes less than a second to return to operation if/when it does happen.

I, too, am interested in when the 12FG and the FASST modules for the older radios will be available. I will splurge on a 12FG once they have been out a few months, I already have 4 6ch receivers that will work with it. Alas, they won't work with the modules for the older radios.

The nice thing about this hobby is that you can use whatever you want.

Bob R.

[Hammbone]

72Mhz is not line of sight. It will go around objects and still get to the rx.
Manufacturers of 72Mhz systems do not warn you that the signal may get blocked by solid objects which get in the way.

Jim

[magicswanson]

JEFFRO503:

http://www2.towerhobbies.com/cgi-bin...?&I=LNRTU7&P=G

It says "Late Sep", which means Oct-Nov. Pretty much the end of the season here.

Doug

[toprudder]

	Quote: Originally Posted by Hammbone
	72Mhz is not line of sight. It will go around objects and still get to the rx. Manufacturers of 72Mhz systems do not warn you that the signal may get blocked by solid objects which get in the way. Jim

http://en.wikipedia.org/wiki/Line-of-sight

In particular, look at the section "how do cell phones work".

Bob R.

[Julez]

Hi!

	Quote:
	What about the fact that 2.4Ghz can't see through carbon fiber, metal,

What about the fact that xxMHz can't do this either?

	Quote:
	What about the fact that 2.4Ghz can't see through [] fuel tanks, people, trees, etc

This is not a fact, this is outright wrong. As long as fuel tanks are not made of conductive material, 2.4GHz has no problem penetrating them.
People, trees, etc: See the file attached, 250m in urban area, 3 houses, 100m of forest in between, no reception problems.
So much for "Line-of-sight".
Someone's gotta get his facts straight, I guess.

	Quote:
	Then you have the problem of 2.4Ghz rx's locking out if the voltage goes below a certain level................ I've never heard of 72Mhz rx's doing that.

Search RCG for "Berg sleeping sickness".

	Quote:
	It seems like you are just ignoring this info

Do you mean ignoring info, like this?

	Quote:
	Does your engine ever get between your tx and your rx? Do any of your planes have carbon fiber on them? If they do, would the carbon fiber sometimes get between your tx and your rx? Do your servos sometimes get between your tx and your rx? Does metal or carbon fiber landing gear ever get between your tx and your rx?

Everything happened so far, and no problems so far. In the bginning, I was very careful to place the antennas like the manufacturer advised.
Now, I just jam them somewhere between batterys, servos, cables, or ESC's. Speck'd out my 3.1m glider with such a setup, and never had any problems on my gas planes either. One of the problem has vanished: 2.4GHz is completely immune to metal noise, which caused problems on this plane before.

Cheers,

Julez

[Hammbone]

	Quote: Originally Posted by toprudder
	http://en.wikipedia.org/wiki/Line-of-sight In particular, look at the section "how do cell phones work". Bob R.

Funny you bring up cell phones. I understand that a lot of them use 2.4Ghz. Ever hear of a dropped call? Ever get a call that's "breaking up"?

If you guys want to fly on 2.4Ghz, go right ahead and do so. I hope you don't have any problems. I'm going to keep flying on 72Mhz. I trust 72Mhz a lot more.

Happy flying,

Jim

[Hammbone]

	Quote: Originally Posted by Julez
	Hi! What about the fact that xxMHz can't do this either? This is not a fact, this is outright wrong. As long as fuel tanks are not made of conductive material, 2.4GHz has no problem penetrating them. People, trees, etc: See the file attached, 250m in urban area, 3 houses, 100m of forest in between, no reception problems. So much for "Line-of-sight". Someone's gotta get his facts straight, I guess. Julez

How many times do I have to say this. I am not making up what I said. It comes directly from the manufacturers of 2.4Ghz. They are the ones that say it is "line of sight", they are the ones that say it can't penentrate solid objects. Send them an e-mail and tell them to get their facts straight. I'm sure you know much more than they do.
Why do you think they have to use 2 different rx antennas going in different directions? 72Mhz doesn't need to do this. What does that tell you about line of sight and object penetration?

Fly what you want. I hope you don't have any problems.

Jim

[Rolling Thunder]

Jim, Which Mfg are your referring to?

I would like to know the real facts vs Urban legend.

[Hammbone]

I've read it in a few different places. The one that comes to mind is a long thread somewhere about Extreme Link. The owner was involved in the thread and he said this.

I've also been told in person by reps at both the Futaba and JR booths at the Toledo show this year.

I assume that this stuff is in the directions that come with the systems as well.
I've heard people talking about what the directions say about rx placement, how it has to be away from carbon fiber, metal, and other electronics.

You haven't heard this anywhere?

Jim

[toprudder]

Well, I think this thread has gone WAY off topic. We aren't getting anywhere with this 2.4ghz good-or-bad discussion, lets stick to the thread subject.

When is the 12FG going to hit the market? I'm anxious to see it happen soon.

I keep seeing reviews of the Futaba 12FG (just read one in R/C Reports) but it ends up being the 12FGA 72mhz and not the 2.4ghz 12FG. Kind of a let down. I guess these are identical transmitters with the exception of the rf module used?

Bob R.

[Hammbone]

Rolling Thunder,
I just did a quick search for "line of sight" on the JR/Sektrum support forum. It is mentioned in several places that the Spektrum system is line of sight. I haven't searched the Futaba forum yet.

Jim

[Hammbone]

Just did a quick search on the Futaba support forums and found this:

Regular fiberglass should be OK, but you'll have to see what other structures may block signals. Large engines can contribute to incoming signal attenuation if you're flying directly toward the transmitter.

Carbon frames in helis may or may not present a problem. It all depends upon the radio's installation and antenna location. As long as the antennas have a clear "view" of the transmitter in all flight attitudes, you'll have no difficulties. With the Futaba FASST receivers, you'll need at least one of the two antennas to have clear exposure to the transmitter on a line -of- sight basis.

We'll have to get back to you on the voltage issue...we don't have a number on that one.

_____________________________

Bill Baxter, Manager Hobby Services/Futaba Service/North America
3002 N. Apollo Dr. Ste. 1 Champaign, IL 61822 USA
Service Phone: 217 398-0007
Email: hobbyservices (at) hobbico.com

[Hammbone]

If I remember correctly, the thread I reffered to earlier about extreme link was on RCGroups back in Feb or March.

I agree that it's important to get facts and not just hearsay.

This info is all over the place. Just do some searches and you'll find it.

Jim