Gonzalo38

Maybe I was reading it wrong..... you may have a point.

Next weekend I will do a test with the antenna in different positions to see which one gives me a the stronger signal.

Maybe pointing the antenna up is the way to go.

rc4flying

My Feedback: (21)

I have always pointed my antenna on my TX's straight up or down depending on the Futaba 12, 14 or 18 transmitters i fly. And the RX in the plane at 90 degrees with one in a vertical position and the other in a horizontal position. Have never seen any problems.

bpoates25

Gonzalo38,

Straight from the Futaba manual from the 7C on page 18.

18
Transmitter Antenna
1. The transmitter antenna is adjustable so please make sure that the antenna is never pointed directly
at the model when flying as this creates a weak signal for the receiver.
2. Keep the antenna perpendicular to the transmitter's face to create a better RF condition for the
receiver. Of course this depends on how you hold the transmitter, but in most cases, adjusting the
transmitter antenna so that it is perpendicular to the face will give the best results. Please adjust the
transmitter antenna to the way you hold the transmitter.

The tip is the weakest signal, so having the antenna pointing up 90 degrees from the face of the transmitter will give you the best signal. I have personally lost a plane while having the antenna laying on it's side. The antenna would not stay up by itself, and I didn't notice it had fell over. Lost the plane at the far end of the field to my right. Right where the antenna was pointed. Sent it in to Futaba and they corrected the problem with the antenna. It shipped from the factory that way. Learned to always check my antenna orientation.

Boomerang1

You have to sort the crap from the clay!

From 4 pages of sniping, bagging other brands, personal attacks, name calling & conspiracy
theories what do we have?

Antenna orientation?

Frame losses from telemetry systems?

Metal control cables?

Heat issues on early receivers?

Anyone else have anything USEFUL to add?


Thanks for the original post Andy.

John.

VF84sluggo

My Feedback: (55)

The way I understand it is to picture the wave from the tx antenna as a donut, with the antenna in the hole and perpendicular to body of the donut. Then, with the antenna positioned vertically, tip either pointed up overhead or down to the deck, the signal "donut" is then propagated out from you (and around you). As was mentioned by Craig B, the weak part of the signal (i.e. the hole) is then oriented overhead or down to the ground...neither place of which your jet should normally be.

Boomerang1

Are you a cop?

VF84sluggo

My Feedback: (55)

lol...

rhklenke

My Feedback: (24)

Here are some pictures of the radiation pattern (in 2D and 3D) of a dipole antenna. The "nulls," or points of low power are at the 2 ends of the antenna.

BTW, I think its best to orient your antenna towards the ground, but not directly straight down (or straight up). The maximum power is radiated out at 90 degrees from the axis of the antenna so you you want the antenna to be perpendicular to your line-of-sight to the model. Since you are usually looking up at an angle of 20-40 degrees plus towards your airplane, you want the antenna to be at an angle of 90 degrees to this, and that is easier to do with the antenna pointed down, not up.

Bob

Rv7garage

My Feedback: (10)

Whatever, bud. I don't know Andy from Adam, and my statement still stands. If you're going to make a statement about failures, then you need to come back with hard evidence of such, not vague innuendo ... or you're just blowing smoke. You can defend your buddy all you want, but that's exactly what was done.

Jim Branaum

My Feedback: (3)

Unfortunately that piece of non-trivia seems to be hidden from the average modeler. I learned about antenna propagation complements of Uncle Sam's Misguided Children, so I have taken similar steps about antenna orientation.

Cractus, common sense isn't and RCU is not unworldly enough to change that.

VF84sluggo that is a great description of signal propagation with this equipment - accurate, clear, and concise.

rhklenke, I would not point the antenna towards the ground because that is where the 'ground plane' is. While there is not physical connection to our equipment, why complicate matters and allow or encourage a secondary propagation from hidden debris (a buried fence line got me once)

SkidMan

My Feedback: (17)

Here is another diagram of the radiation pattern on linear antennas.


The two circles are the cross section of the "doughnut" mentioned earlier. The punchline is that you want your antenna perpendicular to your aircraft.

Left or right, horizontal with the ground, isn't too bad as long as you keep your radio towards your aircraft.

Better yet is what someone mentioned, 45% or so down toward the ground or folded 45% back, past vertical - dependent upon how you hold your transmitter. (Like rhklenke said)

The worst thing you can do is to point the tip of the antenna towards the plane.

Some companies are now using multiple antennas to minimize antenna positioning issues. You will also see multiple antennas on WiFi access points and routers for the same reason.

Keep in mind that the protocols used in our radios are designed to be very fault tolerant; unless you utilize a means of monitoring the quality of the data link it is pretty much impossible to distinguish between a system (transmitter, antennas, and receivers) that is operating marginally and one that is operating well. If your installation is marginal it is just a matter of time until you have a problem.

Paul

SkidMan

My Feedback: (17)

Jim Branaum - Pointing one end of the antenna toward the ground not any different than pointing it towards the sky. The power radiated off of each end of the antenna is essentially the same (the far end, or the end fastened at your transmitter). The real radiated power is perpendicular to the antenna axis, not the end of the antenna.

warbird72

My Feedback: (79)

I see no real facts yet myself! Please post them when you have them! Im also using fasst 2.4 not one issue!
Please let us all know. Thank you.

Craig B.

Bob, sluggo and skidman have described perfectly what I was referring to. Thanks for the elaboration guys. On my 18mz I point my antenna down an forwards at my feet, so that is where my weakest signal will be. Range won't be a problem there!

It is a pity that more emphasis is not placed on this by the radio manufacturers in the manuals. If you point those nulls at a model just after takeoff or on approach for landing on an install that may be less than optimal for some reason, you are playing Rc Russian roulette. Time for a new poll.....

Craig B.

hi speed, thanks, nice to know I am on the money from someone in the business! Hopefully this thread will result in more people checking this and fewer lockouts.

rc4flying

My Feedback: (21)

Craig B

How are you pointing your TX antenna towards the ground on the 18MZ ? I can not rotate my antenna to do that on my 18MZ. I could on my 12 and 14MZ but not the 18.

cloudancer03

My Feedback: (22)

I never saw a warranty that read bullet proof. So its possible there was a lockout but I know unlike another brand I once had that was a frequent occurrence.so if it did happen I think the guys flying that particular futaba radio should be informed and no be evasive and I nunedo.spell itand have a real conversation.opening up a post titled whats wrong with futaba is not a good intro.

sskianpour

My Feedback: (2)

Most important from this thread is that we should take this opportunity to perhaps come up with different troll-like synonyms that differentiate actual trolls, with pretend-trolls, and then wannabe trolls (peer pressure). Maybe we can do some sub-categories like Gnomes, Goblins, Elves, Dwarves, Sprites, maybe a billy goat or two?

Andy how do you feel about being a half-troll, part Gnome/part-human wizard or paladin but with lots of hit points and melee attack? Maybe an elf?


Shaz

cloudancer03

My Feedback: (22)

Thee post is titled whats up with futaba.then it says there were some lockouts but the information is somehow secret.that tends toraise eyebrows.if more information is shared then we can discuss it intellegently without brand bashing.i have had a radio warranty that says this radio is bullet proofing

afterburner

My Feedback: (18)

Same with mine. Right after reading that I checked. it only rotates 45 degrees from parallel to the face to straight up although when I first had the radio for just a few weeks I thought I had closed the case after test running an engine in my backyard and when lifting the case by the handle the radio fell out and the antenna had popped out. I snapped it right back in but now I wonder if I had snapped it in the wrong position. I do remember always pointing the antenna on my 12 FG down but the 18 I point up.

Turbulence

My Feedback: (76)

Tony's accident happened at my home field and I also fly Futaba. I don't fly as fast or as far so Tony, but I would be more than happy test any combos you want in some of my lower priced planes. Now, the only other difference between the speed and range is I do NOT use PowerBox for anything, if someone wants to volunteer one, I can certainly test that too. Now, We know Tony was using one, and I am under the impression that the accident in PHX also had one, can we confirm if it was the same model/type? I have 2 10C and a 14MZ I can use to test with. Can we also look into finding out the TX's used when the planes went in? Also what RX and was there any of the new a-bus or telemetry? (I don't have or use that either). Let's first see if we can get details about the actual set up used.


Ralph

dbsonic

My Feedback: (3)

There are 2 things crucial with Futaba 2.4Ghz.

1. the rx antennas need to be fixed at 90 degrees.
2. the tx antenna orientation must be set such that the side lobes cover the flying area.

Short of this is likely non-optimal with possible failsafe consequences. Since most typical Futaba setups don't have frame loss counters you just have to follow the above and trust it works correctly. Personally I like the idea of having frame loss counters since there are these variables...

radfordc

My Feedback: (14)

Andy, surely this isn't your first time on the internet. Anyone with half a brain and a keyboard is allowed to be as virulent as they please.

rhklenke

My Feedback: (24)

Oh, Oh, can we add some enchanted bunnies too?

Bob

rhklenke

My Feedback: (24)

If you can't point it down, then up is probably almost as good. You just want to make sure that for maximum signal strength at the aircraft. the antenna does not point at the aircraft. Its easy to verify during range checking that this is the worst orientation for the TX antenna and results in significantly lower range...

Bob