chattering servos, PPM, 60 feet distance - normal?  
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All Forums >> Radios, Batteries, Clubhouse and more >> RC Radios, Transmitters, Receivers, Servos, gyros >> chattering servos, PPM, 60 feet distance - normal?
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chattering servos, PPM, 60 feet distance - normal? - 6/23/2008 4:19:25 PM   
solpete


 

Posts: 19
Joined: 5/25/2008
From: Uppsala, SWEDEN
Status: offline 		Hi! Are chattering servos normal during these conditions?

- PPM mode (futaba 7 channel)
- holding receiver in hand, antenna dropping towards the ground (vertical)
- Transmitter placed on ground
-open field, small houses

While walking away from the transmitter, holding servo in the hand (preferably against the ear), a chatter is heard and from time to time - SMALL movement of the servo arm.

Small chattering occurs at 30-80 feet, especially while moving away or towards the transmitter when the transmitter antenna is IN
Small chattering occurs at 300-360 feet, especially while moving away or towards the transmitter when the transmitter antenna is OUT

I am considering buying a PCM receiver, because I got no chattering with that one

       Post #: 1

RE: chattering servos, PPM, 60 feet distance - normal? - 6/24/2008 5:07:56 AM   
BuschBarber


 

Posts: 684
Joined: 1/7/2002
From: Rochester, NY, USA
Status: offline 		PCM doesn't chatter because it goes into Failsafe when the signal is lost. You determine what positions you want the servos on each channel to go to, when you have a Failsafe condition, and that is where the servos will go.

With PPM, the servos will chatter as you lose and regain the signal.

Servo chattering can be caused by a bad servo, low battery, bad servo extensions, weak Tx signal, and RF noise. If use PCM, and still had servo chatter, it would probably narrow down the cause of the problem.

Ideally, you would not want to be holding the receiver. Set it down on a table, with the servo, and do a Range Check. With my 9CAP, I can get over 200ft, Tx antenna collapsed, and no chatter, even in PPM mode. Having your had near the Rx antenna could affect the results.

(in reply to solpete)
       Post #: 2

RE: chattering servos, PPM, 60 feet distance - normal? - 6/24/2008 6:02:14 AM   
freeair


 

Posts: 365
Joined: 5/10/2008
From: queensland, AUSTRALIA
Status: offline 		yes place the rx on a bench or whatever so the antenna is off the ground and also hold onto the tx .

(in reply to BuschBarber)
       Post #: 3

RE: chattering servos, PPM, 60 feet distance - normal? - 6/24/2008 7:31:04 AM   
solpete


 

Posts: 19
Joined: 5/25/2008
From: Uppsala, SWEDEN
Status: offline 		Yesterday I called a guy that deals with Futaba Support here and he told me a chatter here and there is normal even at 60 feet with antenna collapsed. I tried changing servos, no difference. I tried changing crystals and no difference. Then I Changed the receiver and no difference. Then I Used my original receiver, but changed crystals and a new 9 - channel radio and guess what - no difference. I am quite sure that chattering at 60 feet is normal after talking to the support. What I guess many people do, is that they put the model on the ground, walk away 100 feet and check if the servos move. That they do, but what people dont know is that the servos chatter a lot at that distance but its only noticable if you listen and watch the servos really up close.

I bought a Futaba 8 channel double super 1024 PCM receiver yesterday, because I am tired of the chattering. I know what the risks are

(in reply to freeair)
       Post #: 4

RE: chattering servos, PPM, 60 feet distance - normal? - 6/24/2008 11:52:00 AM   
BuschBarber


 

Posts: 684
Joined: 1/7/2002
From: Rochester, NY, USA
Status: offline 		There are those who swear by PCM and others who say they would rather fight their model to the ground rather than have it lock out. Some say it reduces the chances of interference and some disagree. I know with the 9CAP, you only get the 9th channel with PCM.

I have had good luck with PCM. When I do a Range Check and I backup while moving the Control Surfaces, if there is a Range problem, the Control Surface will hesitate. Also, because channels go into Failsafe in order from 1-9, I have seen a case where I mix Elevator halves, on Ch2 and Ch8, for example, and as I back up for a Range Check, Ch2 will go into Failsafe first, and then Ch 8 a second later, or vice versa depending upon when the signal loss occurs. It is annoying to see both Elevator halves moving together and then one half hesitate before the other.

Switching to 2.4 has so far not glitched on me at all and I was on 72Mhz for 30 years. What a relief. I still fly on 72Mhz, but I am slowly replacing my 72Mhz receivers. Some Gasoline engines caused me endless problems with RF noise.

(in reply to solpete)
       Post #: 5

RE: chattering servos, PPM, 60 feet distance - normal? - 6/24/2008 11:32:18 PM   
slarty


 

Posts: 112
Joined: 3/15/2008
From: Sluff, UNITED KINGDOM
Status: offline 		The problem is that the transmitters invariably rely on a human holding them. As you notice there is a single antenna sticking out of the transmitter. This whip antenna is not very efficient, when a human holds the transmitter, you form part of the antenna circuit via capacitive coupling and you effectively form the earthy part of a dipole. This is a more efficient antenna and so you should see an improvement.

(in reply to BuschBarber)
       Post #: 6

RE: chattering servos, PPM, 60 feet distance - normal? - 6/25/2008 8:34:55 AM   
solpete


 

Posts: 19
Joined: 5/25/2008
From: Uppsala, SWEDEN
Status: offline
quote:

ORIGINAL: slarty

The problem is that the transmitters invariably rely on a human holding them. As you notice there is a single antenna sticking out of the transmitter. This whip antenna is not very efficient, when a human holds the transmitter, you form part of the antenna circuit via capacitive coupling and you effectively form the earthy part of a dipole. This is a more efficient antenna and so you should see an improvement.


I didnt think about that one Of course I will get better range check if I HOLD the transmitter hehe :=) Mostly Ive been on my own. Anyway Yesterday I did a range check with my new PSM receiver. I put the model on a table on an open field. I walked backwards and after about 150-200 feet, I still didnt get any sloppy movement of the rudders. I think I am confident now that my setup works correctly and that Ive been worrying too much

(in reply to slarty)
       Post #: 7

RE: chattering servos, PPM, 60 feet distance - normal? - 7/12/2008 8:04:08 PM   
bertnhank


 

Posts: 30
Joined: 11/24/2006
From: Calver City, KY, USA
Status: offline 		JUST BOUGHT A FUTABA FP-T7UAP SUPER. I WAS TOLD IT WAS FOR 4 MODELS, 7 CHANNELS. DOES ANY ONE KNOW ANYTHING ABOUT THIS RADIO.

(in reply to solpete)
       Post #: 8

RE: chattering servos, PPM, 60 feet distance - normal? - 7/13/2008 2:29:51 AM   
BuschBarber


 

Posts: 684
Joined: 1/7/2002
From: Rochester, NY, USA
Status: offline 		I had a Futaba 7AUP, a 7AUPS, and an 8AUPS. I only have a 9C, now, and a JRXP9303.

I just happen to have the manual for the 7AUPS. It has 4 model memories. It is a good radio although it is older technology.

(in reply to bertnhank)
       Post #: 9

RE: chattering servos, PPM, 60 feet distance - normal? - 7/13/2008 8:39:39 PM   
bertnhank


 

Posts: 30
Joined: 11/24/2006
From: Calver City, KY, USA
Status: offline 		I asked the question because the guy I bought the radio from sent me a manual for an older radio, and the radio was a Super.

I went to Futaba's website and found the current or most current manual which showed how to select models.

Don't know if I will ever use all the functions, but I have 4 planes ready to fly.

(in reply to BuschBarber)
       Post #: 10

RE: chattering servos, PPM, 60 feet distance - normal? - 7/13/2008 9:24:06 PM   
BuschBarber


 

Posts: 684
Joined: 1/7/2002
From: Rochester, NY, USA
Status: offline 		I originally bought the 7AUPS, from a friend, who did not want it anymore. I had a H9 UltraStick and I wanted to utilize the Crow (Butterfly) features of that plane. The Ailerons were split into half Aileron, half Flap. Each surface had it's own servo, including each Elevator half.

As it turned out, the 7AUPS was not the radio for that task. I had to use a Pmix to mix the Elevator halves. I could not then mix that Pmix with the Flaps as only the Elevator side of the Pmix could be mixed with the Flaps.

I bought an 8AUPS and it resolved all my problems. The 8AUPS came with the Ailevator program which allowed me to mix the Elevator halves on ch 2 and ch8, by default. When I then mixed Elevator with Flaps, both Elevator halves responded.

Also, the 8AUPS has the Acro, Heli, and Sailplane mode. Sailplane mode supports Butterfly (Crow).

It all comes down to how complex the model is you intend to fly, how many channels you need, and whether or not you need additional third party devices.

Don Edberg published several books on Futaba Programmable radios that specifically talked about the 7ch and 8ch. He describes scenarios where you would need to use multiple Pmix's, for example, to put Flaps on a switch instead of a knob. I would have never thought of using that method if someone had not told me

My JR XP9303 comes with Flaps on a three position switch. That, and the additional Flight Mode options lured me away from Futaba, at the time. I am sure that Futaba's 12ch and 14ch have lots of neat features, as well, but the 9CAP disappointed me.

(in reply to bertnhank)
       Post #: 11

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