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Poor Transmitter Antenna Positioning may Cause Lockouts

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Old 04-20-2014, 09:40 AM
  #51
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for at least 10 yrs ive been to jet contest contest all ove the usa>> seen a lot crash the first thing they call out is something wrong with the radio what about all the other things they stuff in to the plane other parts can caush a crash
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Old 04-20-2014, 09:46 AM
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One thing I find alarming is how little attention people pay to their transmitter antenna orientation, particularly with the Futaba 18mz and 12X. I have and fly with both an 18MZ and JR 12X so can comment impartially. Regardless of the brand of transmitter you use, we should all be more conscious of the polar nature of the transmitted signal (i.e.. it is at its weakest along the long axis of the antenna and strongest perpendicular to the antenna) and that should taken into account when orientating it prior to flight.

So many people seem to just pull the transmitter out of the case and fly without changing the antenna orientation. The manufacturers made them adjustable for a reason! With both the 12X and the 18mz, when you pull the transmitter out of the case, the antenna ends up orientated parallel to the runway, so the transmitted signal is weakest at either extreme of the airfield on the same line as the runway (or thereabouts, depending on how close you are to it), which is often when the model is also furthest away! You are just asking for trouble if you do that.

I always point my antenna over my head or at the ground in front of me which will result in a stronger signal being seen at more points around the periphery of the field....the weakest poles of the transmitted signal are then located over my head or at my feet, where my model should never be going anyway.

Everyone always points the finger at the receiver end if there is interference, and whilst there may be on board factors degrading the reception quality, you can improve your chances of success by paying proper attention to transmitter antenna orientation to maximise your visible signal strength.

And no, I don't work for Lockheed Martin, Nasa or Boeing, but I did pay attention in physics lectures at uni..... I have seen many experienced pilots flying at Florida Jets, Top Gun etc (albeit on DVD), flying with their antenna horizontally positioned, parallel to the runway......bad idea guys, unless you like weak reception on landing approach or just after takeoff. We pay so much attention to receiver antenna orientation.....which is great but that is only half of the equation!! Go and check out Carsten's telemetry thread for the proof.

There is so much variability that can be introduced by the user that it is hard to distil out the reality of these signal loss accidents without knowing all of those small but highly relevant details.
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Old 04-20-2014, 09:49 AM
  #53
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Quote:
Originally Posted by dubd View Post
This isn't a thread about Futaba vs Spektrum so stop trying to make it into one.

Agreed, I have flown Kraft, Airtronics, JR, Spektrum and now Hitec. I have not noted any system being more failure prone then the others during the respective time period. IMO most issues are installation related mostly unknowingly. The manufacturers could be doing a better job at educating us as to what can cause signal degradation.

Craig, I work for Randtron Antenna Systems, your comments on TX antenna orientation are spot on.

Last edited by speedracerntrixie; 04-20-2014 at 09:53 AM.
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Old 04-20-2014, 10:25 AM
  #54
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Quote:
Originally Posted by All Day Dan View Post
Sorry Andy but it's the JRs and Spectrums that are going in at the field that I fly at and it's many more than 8. Dan.

Why haven't you posted anything? Whats going on?
Scott
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Old 04-20-2014, 10:36 AM
  #55
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Started flying about 5 years ago ,I started with other brand and there were problems,switched over to Futaba and have never had a problem since. Have 17 planes today all with Futaba and will use no other
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Old 04-20-2014, 10:57 AM
  #56
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Quote:
Originally Posted by Airplanes400 View Post
OK. This happened to at least one jet and one WWII P-47. Both were airplanes built by quality builders. The other airplanes remain unknown as to what type. So far, so good. Hopefully, those that it happened to will join this discussion to provide details.

The word, "troll" is used too freely around here. Just because someone starts a discussion or has an opposing viewpoint, does not make them a "troll." Yet people continue to throw that word around.
+1

common sense is a beautiful thing but dwindling on rcu. We should encourage fellow modelers to share their builds, ideas, concerns without launching personal attacks. Otherwise, it's going to be pretty boring around here.
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Old 04-20-2014, 11:00 AM
  #57
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Been flying with Futaba for more than 10 years without a problem. I've had the 7C and 14MZ and still have two (2) 10C and the 18MZ. They have always performed without a problem.

Having said that, I have seen that my frame losses have skyrocketed when using telemetry ON compared to when it's OFF. My Powerbox would show 30 frame losses without telemetry and then go up to over 600 when telemetry is activated.

You can select how often you want your telemetry data updated on your radio...... the fastest your selection, the more losses you get.

Could this be a problem for the 7008 and 7003 SBuss receivers ?
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Old 04-20-2014, 11:01 AM
  #58
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no matter how good you are you will crash at sometime
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Old 04-20-2014, 11:03 AM
  #59
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what is a power box?
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Old 04-20-2014, 11:12 AM
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Quote:
Originally Posted by speedracerntrixie View Post
I think pointing the finger at a specific manufacturer is pointless. For the most part all the major players use pretty much the same technology.
No, they are different.

Quote:
Originally Posted by DrScoles View Post
What puzzles me, is why does jr need satellites and all that confusion when futaba can accomplish it with two little wires?
Because they are different...and its not confusing, in the least.

Quote:
Originally Posted by speedracerntrixie View Post
I will agree with Andy as I had flown IMAC with Tony Quist for a few years and his installs were always top notch.
Tony's stuff is SOLID. Andy is no troll......lets keep the discussion civil and we all may learn something.
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Old 04-20-2014, 11:15 AM
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The only reason the word "troll" was used, is because a statement was made about failures with no specific info to back it up. Then, when specifics were requested, there was some back-pedaling, and resistance to giving the specifics asked for. In other words, it seemed like unsubstantiated hearsay, which is what Trolls promulgate. All clear on this? If we are going to make statements, we should have hard evidence or first-person witness of the event, otherwise it is just talk.
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Old 04-20-2014, 11:35 AM
  #62
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Quote:
Originally Posted by Rv7garage View Post
The only reason the word "troll" was used, is because a statement was made about failures with no specific info to back it up. Then, when specifics were requested, there was some back-pedaling, and resistance to giving the specifics asked for. In other words, it seemed like unsubstantiated hearsay, which is what Trolls promulgate. All clear on this? If we are going to make statements, we should have hard evidence or first-person witness of the event, otherwise it is just talk.
A troll is an anonymous person posting things just to get a rise from people and causing mayhem. Andy is NOT anonymous, many here know him, respect him and consider him a friend. Given that, he is going to get more than the benefit of the doubt when it comes to information he may have. All clear on that?

If its not the radio, something causes models to go down....lets keep this on point and maybe we can all learn something that may save a model.
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Old 04-20-2014, 11:36 AM
  #63
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Quote:
Originally Posted by Craig B. View Post
One thing I find alarming is how little attention people pay to their transmitter antenna orientation, particularly with the Futaba 18mz and 12X. I have and fly with both an 18MZ and JR 12X so can comment impartially. Regardless of the brand of transmitter you use, we should all be more conscious of the polar nature of the transmitted signal (i.e.. it is at its weakest along the long axis of the antenna and strongest perpendicular to the antenna) and that should taken into account when orientating it prior to flight.

So many people seem to just pull the transmitter out of the case and fly without changing the antenna orientation. The manufacturers made them adjustable for a reason! With both the 12X and the 18mz, when you pull the transmitter out of the case, the antenna ends up orientated parallel to the runway, so the transmitted signal is weakest at either extreme of the airfield on the same line as the runway (or thereabouts, depending on how close you are to it), which is often when the model is also furthest away! You are just asking for trouble if you do that.

I always point my antenna over my head or at the ground in front of me which will result in a stronger signal being seen at more points around the periphery of the field....the weakest poles of the transmitted signal are then located over my head or at my feet, where my model should never be going anyway.

Everyone always points the finger at the receiver end if there is interference, and whilst there may be on board factors degrading the reception quality, you can improve your chances of success by paying proper attention to transmitter antenna orientation to maximise your visible signal strength.

And no, I don't work for Lockheed Martin, Nasa or Boeing, but I did pay attention in physics lectures at uni..... I have seen many experienced pilots flying at Florida Jets, Top Gun etc (albeit on DVD), flying with their antenna horizontally positioned, parallel to the runway......bad idea guys, unless you like weak reception on landing approach or just after takeoff. We pay so much attention to receiver antenna orientation.....which is great but that is only half of the equation!! Go and check out Carsten's telemetry thread for the proof.

There is so much variability that can be introduced by the user that it is hard to distil out the reality of these signal loss accidents without knowing all of those small but highly relevant details.
Just want to point out that there are radios sold with fixed antenna orientation; Jeti DS-16 / DC-16 for example.
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Old 04-20-2014, 11:41 AM
  #64
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Quote:
Originally Posted by sideshow View Post
No, they are different.



Because they are different...and its not confusing, in the least.



Tony's stuff is SOLID. Andy is no troll......lets keep the discussion civil and we all may learn something.

perhaps the the work technology may not have been the best choice however the same frequency at the same power levels is being used. I believe each one is using proprietary encoding and some use signal hopping but the basics are the same. If not then please enlighten us.
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Old 04-20-2014, 11:53 AM
  #65
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This guy is only trying to help. All of you ripping him are true dbs. Now I remember why I gave up on this site. A hole nation here
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Old 04-20-2014, 12:04 PM
  #66
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Quote:
Originally Posted by Gonzalo38 View Post
Been flying with Futaba for more than 10 years without a problem. I've had the 7C and 14MZ and still have two (2) 10C and the 18MZ. They have always performed without a problem.

Having said that, I have seen that my frame losses have skyrocketed when using telemetry ON compared to when it's OFF. My Powerbox would show 30 frame losses without telemetry and then go up to over 600 when telemetry is activated.

You can select how often you want your telemetry data updated on your radio...... the fastest your selection, the more losses you get.

Could this be a problem for the 7008 and 7003 SBuss receivers ?

Great info Gonzalo, thanks for pointing this out. For those who know how to read the fine lines, they already know what to do in their setups.
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Old 04-20-2014, 12:41 PM
  #67
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I think until we know the specific info on the lock outs such as their set up and models of equip used I don't see there is much to discuss.
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Old 04-20-2014, 12:48 PM
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the only thing I know of out west is there is GPS tests going on all summer sporadically around Truth or Consequences.. It was in the aviation notam system.. I don't know the extent of it, or what freqs are tested..

You know every spring when flying begins to pick up, I hear of lockouts.. maybe its just because the activity level is picking up, and guys are flying stuff that sat all winter.. dunno..

I for one, hope everyone has a busy summer, lots of flights, lots of beer, and lots of kero burned..
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Old 04-20-2014, 12:49 PM
  #69
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Quote:
Originally Posted by sirrom View Post
Andy,
All due respect, but it sounds as a transmitter war is what you are trying to start. If you are going to make the allegation about 8 specific lockouts you should be prepared to give up your so-called secret sources. Unfortunately it makes you look as if you are just trying to start a rumor. What would be the difference if I started a thread on another site that went, "Hey I heard Andy Andrews was arrested for 8 different charges!" and when asked who said it, all I could say was "Oh I can't divulge my source." It makes me look like an ass for even saying one word without being willing to provide some kind of proof. This is the kind of post that reminds me of the national enquirer when they have grainy/fuzzy pictures of bigfoot.
Oh and been flying FASST since it came out without one lockup and I fly nitro, gas, helis, electric, and jets.

Patrick
why does everything on RCU have to be a conspiracy ? I LAUGH at THEE
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Old 04-20-2014, 12:59 PM
  #70
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LOL if i was flying a 10,000.00 ride and heard there Might be a problem , i'd be asking too. But i guess people here don't take concerns seriously enough to try to help, just throw rocks . what people don't care to understand is that every radio system is without fault. but given what I've read here ,FuBlaba is perfect. You are forced to trust a untrustworthy system which can only function within it's abilities . so if a weak area is there , most likely it will eventually show itself. so if you have something to add , by all means bring it up. keep asking Andy ,you might get someone who actually knows something.. p.s. wish i could make KJ this year. off to WOD this year. WB_1
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Old 04-20-2014, 01:07 PM
  #71
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Andy
3 lockouts happened at my field with Futaba 18, in all 3 we concluded that the problem was antena position, in all 3 the anntena was ponting sideways
Since we all are pointing it upwards not a single one has ocurred
we tested the theory doing a range check and when the antena was pointing directly to the plane we had lot less than half of the distance
BTW, I think this applies to every brand
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Old 04-20-2014, 01:44 PM
  #72
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Quote:
Originally Posted by Craig B. View Post
One thing I find alarming is how little attention people pay to their transmitter antenna orientation, particularly with the Futaba 18mz and 12X. I have and fly with both an 18MZ and JR 12X so can comment impartially. Regardless of the brand of transmitter you use, we should all be more conscious of the polar nature of the transmitted signal (i.e.. it is at its weakest along the long axis of the antenna and strongest perpendicular to the antenna) and that should taken into account when orientating it prior to flight.
Concur.

Further, I see guys put their rx antennas 90 deg apart, but both are horizontal. In my setup, I make sure one of the rx antennas is parallel to the longitudinal axis of the jet, the other oriented along the vertical axis. This way my antennas are 90 deg apart, but two different geometric planes are also covered. I also place my rx as near the nose as possible, with the antenna ends along the inside skin of the jet. Another benefit with this location is that in my installs typically there are no "noisy" gizmos or gadgets installed within several inches of the antenna ends.

This, coupled with pointing my tx antenna vertically, hopefully gives the tx/rx signal the best chance of success...knock on wood. In any case, hearing of mysterious "lockouts", especially when it seems like several are happening in a short period of time, are always a little unsettling.

Sluggo

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Old 04-20-2014, 01:48 PM
  #73
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Quote:
Originally Posted by monjet View Post
Andy
3 lockouts happened at my field with Futaba 18, in all 3 we concluded that the problem was antena position, in all 3 the anntena was ponting sideways
Since we all are pointing it upwards not a single one has ocurred
we tested the theory doing a range check and when the antena was pointing directly to the plane we had lot less than half of the distance
BTW, I think this applies to every brand

Interesting since the Futaba manual states something different. It says the strongest signal is when you have the antenna to the side and not pointing upwards.
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Old 04-20-2014, 02:02 PM
  #74
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Gonzola38,

What I take from your attachment, is the weakest signal is radiated from the tip of the antenna no matter what direction it is pointed, and the strongest signal is radiated from the sides of the antenna.
So if you have the antenna positioned in a 90 degree direction to your right, the weakest signal is radiated to the right and strongest will be straight to the front of you.
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Old 04-20-2014, 02:12 PM
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Quote:
Originally Posted by Gonzalo38 View Post
Interesting since the Futaba manual states something different. It says the strongest signal is when you have the antenna to the side and not pointing upwards.
Hmm, I know very little about radio wave propagation, it would be interesting to hear from someone who knows whats up. I have a JR radio but radio waves are radio waves.....I remember a discussion about this years ago but couldn't find it....
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