[NSRCA-discussion] Analog Servo RF Masking and....Thanks!

Wed Jul 5 13:57:08 AKDT 2006

Scott,

I had similar problem years ago with different brands of Rx than the Tx..  The final solution was to use the same brand for both.  I think you just had the same experience.  This was more than 10 years ago.  The conditions are different but the results are similar.  I think you just found the reason for your problem and you should be fine.

I am not expert in electronic.  I am not sure when you say "masking".  My way to check is to doing range check.  If works there is not problem PCM or PPM.  I am not sure how the PCM receiver could be "masking" the problem.  The receiver lock out or go to fail safe when does not get the TX signal.  If you want to check what happens when the RX locks out just turn of f the transmitter.  The receiver will control the servos to the pre-programmed position.  You can program that position.  Electronic experts, am I right?  

Good luck at the Nats.  I wish that I could be there.

Vicente Bortone

-------------- Original message -------------- 
From: "Scott Pavlock" <f3aflyer7 at gmail.com> 
Well I think I may have found somthing that works. I put a Futaba PCM receiver in instead of my PPM receiver, and everything seemes to work. No buzzing or glitching. However, could the PCM be still masking my problem, and would there be the potential for lockout? Too much to think about for me thats for sure. I'll have to do some more extensive testing with the PCM reciever to see if it's actually going to help. 

For now, the Jeskys have offered to let me borrow a complete JR TX/RX/Servo set up for the NATS. This is going to be my best way to temporarially solve the problem, and then after the NATS, we will definitely figure out the true root of this problem. It's too odd to let go. Thanks a bunch to everyone who offered setups and what not, the Jeskys live close so its much more feasable. 

I really appreciate everyone's input and it has all helped a great deal. Right now the closest we've gotten is with the PCM reciever. Hopefully that will solve the problem.

Scott

On 7/5/06, R. LIPRIE <RLIPRIE at centurytel.net> wrote: 
The best servos you could get, would be DIGITAL.
                                Matt
----- Original Message ----- 
From: Scott Pavlock 
To: K6XYZ at valornet.com ; NSRCA Mailing List 
Sent: Wednesday, July 05, 2006 11:04 AM
Subject: Re: [NSRCA-discussion] Analog Servo RF Masking and....Thanks!

First, I just want to say thanks a whole bunch to the people who offered me equipment as I've gotten some private e-mails also. It really goes to show how great people are in this hobby. I am, however, going to go through local sources for different equipment. There are a lot of people at my club with plenty of different TX's and RX's in all different brands so instead of trying to rush and get things here so quickly, I would rather get them locally first. Thanks a ton!! 

Next, I want to reiterate my set up because I think this is getting a little confusing.

My current set up which shows NO visible problems is: 
-Futaba 9C with the syntheszed module.
-Hitec Super Slim RX on channel 49. 
-2 Futaba 3010's.
-2 Hitec HS77's.
-1 Hitec HS81MG.
-Duralite 2s2p RX Battery
-MPI 5.6v Regulator.
-MPI HD Switch Harness.
-Cermark gold plated extentions.

Now here is my problem set up which shows the glitch: 
-2 JR 9411sa's
-1 JR 8417
-1 JR 8411sa
-1 JR 3421sa
-The rest is identical.

As you can see, the only thing that seems to make it work is the alanog servos.

Del, they glitch when they are connected and disconnected from the surfaces. More so when they are connected, but I can totally rule out the airframe being the problem. These servos have at least 2 years of flying on them and one of the hypothesis I had was that after being vibrated around for 2 years, theyre now feeling like they should always be doing that, even without a load. Not sure if that's possible, but I'm just throwin out ideas. 

The next thing I am going to test is a Futaba PCM receiver on both set ups. The set up that works will be in the aircraft, and the set up that doesnt will be sitting in the foam transmitter box.

***Important*** 
Yesterday I range tested both set ups. The one that "works" is in the plane, and the one that doesnt (JR digitals) was in the transmitter box. Both tests were done outside on grass. I put the antenna all the way down and walked at least 300 feet with no noticible problem at all when testing the airplane. When testing the digital servos, I was able to walk about 100 feet from the box they were sitting in and thats when they became very noticible glitches. This was both with the antenna at 1 section out, and all the way up. The glitch was reduced when it was all the way out but it was still prevalent. 

On 7/5/06, Dave Harmon <K6XYZ at valornet.com> wrote: 
Which model Futaba rx is it?

Regards

Dave Harmon
NSRCA 586
K6XYZ[at]valornet[dot]com
Broken Arrow, Ok. 
-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto:nsrca-discussion-bounces at lists.nsrca.org] On Behalf Of John Ferrell
Sent: Wednesday, July 05, 2006 9:21 AM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Analog Servo RF Masking and....Thanks!

I have seen this kind of "Twilight Zone" ( I really like that term!) failure in industrial products. The problem is probably present in the Analog setup but the system is not fast enough for it to show.

If the digital servos are trying to latch up on the leading edge of a signal shift they may simply be following switching transients.

I seem to recall a condition where Jr had a filter across the signal at the reciever and Futaba had a filter across the signal at the servo. Since it always seemed to work OK  so the condition was ignored. May be that the filter has become essential. I suppose that we may have reached the point in time that we can no longer ignore the differences in the two systems. 

I have used mixed systems but I have never been comfortable ignoring any engineer's specfications.

When you mix the two systems it is a hack and you become the test pilot...

BTW, my guess is that the glitch can be fixed with a capacitor (100pf?) across the signal at the servo end. But then it might just make it worse!

John Ferrell    W8CCW
"My Competition is not my enemy"
http://DixieNC.US
----- Original Message ----- 
From: John Pavlick 
To: NSRCA Mailing List 
Sent: Tuesday, July 04, 2006 7:07 PM
Subject: Re: [NSRCA-discussion] Analog Servo RF Masking and....Thanks!

Scott A.: Yeah, a possibility - but he says it works OK with the analog servos. It would be worth checking, but if he has another Rx he could just substitute that (probably already did) and see if the problem goes away. Scott P.: Does moving the antenna change anything? You have to find the common denominator. If it's not the Rx then maybe it has something to do with the installation. There is something going on there and I'm not sure why the digital servos make it more apparent. Find someone who knows how to use a 'scope and see if they can help you. This is weird - you guys have the same first name and my last name looks like yours. Maybe we're all stuck in the Twilight Zone...

John Pavlick
http://www.idseng.com

-----Original Message-----
From: nsrca-discussion-bounces at lists.nsrca.org [mailto: nsrca-discussion-bounces at lists.nsrca.org]On Behalf Of Scott Anderson
Sent: Tuesday, July 04, 2006 6:47 PM
To: NSRCA Mailing List
Subject: Re: [NSRCA-discussion] Analog Servo RF Masking and....Thanks!
Hi Scott,

Stupid question, did you send RX out and have it put on a shaker table and checked.. I had a RX issue for over a month and spent time with Tony S. and he found a bad filter on the board.. 

Just my 2 cents from a fellow team member..

Scott Anderson
----- Original Message ----- 
From: Scott Pavlock 
To: NSRCA Mailing List 
Sent: Tuesday, July 04, 2006 6:29 PM
Subject: Re: [NSRCA-discussion] Analog Servo RF Masking and....Thanks!

I've used multiple battery set ups including ones without a regulator on a normal NiCd pack, and also on both a 5.6v regulator and a 6v regulator.

John,

No I don't. I actually have no clue what that is haha.

/nsrca-discussion

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