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

Tue Jul 4 15:30:19 AKDT 2006

Scott:
Digital servos each have their own microprocessor inside and each has it's own clock reference, i.e., each is a new source of low level digital noise in your system, which is coupled directly back to the receiver's decoder section via the servo leads.  My first guess is that there is something in your receiver electronics, probably in the decoder section, that is sensitive to this noise.  Noise sensitivity in the decoder section won't show up as diminished range in alot of cases, you will see this sort-of sympathetic behavior of other servos as the noise is unintentionally integrated into the data pulses that each servo channel is being sent by the decoder.  Could be something else, but I would look to the receiver first.  If you can, swap out for a different brand or model of receiver and see if the problem goes away.

Ed
  ----- Original Message ----- 
  From: Scott Anderson 
  To: NSRCA Mailing List 
  Sent: Tuesday, July 04, 2006 6:47 PM
  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.

    On 7/4/06, John Pavlick <jpavlick at idseng.com> wrote: 
      Do you have access to an oscilloscope?

      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 Pavlock

        Sent: Tuesday, July 04, 2006 5:40 PM
        To: NSRCA Mailing List
        Subject: Re: [NSRCA-discussion] Analog Servo RF Masking and....Thanks!

      I've literally tried EVERYTHING possible to isolate the problem. The only problem I can find is solely in the servos. The battery is bran new (duralite 2s2p), bran new heavy duty MPI switch. I can reproduce the problem with the digis with many different switch/battery/regulator set ups. I know current draw isn't a problem as I've flown this set up for 2 years with no faults. 

      On 7/4/06, John Pavlick <jpavlick at idseng.com> wrote: 
        Scott,
         Well I'm sure you've been through a lot already, but what you need to do is try to isolate the problem if possible. Start with a working setup (the analog servos). Next, add 1 digital servo. If it still works, remove that servo and try another. Only change ONE thing at a time. If it works with 1 digital servo ALL THE TIME, then add a second one. If you start to see problems as you add more digital servos (i.e gets worse with 3 or 4 digital servos but seems to work OK with 1 or 2), look at your battery and switch. What are you using for a battery and switch by the way? If your radio checks out OK (RF-wise) it's more likely that there is a problem with power. I bet you didn't have Rx the batteries checked did you? As you know, analog servos don't draw nearly as much current as digital servos. That could be the problem. If you have any way to look at the voltage when all of this is happening it could reveal some things. One way to do this is to put a servo lead in an unused channel on the Rx, connect it to a voltmeter, turn everything on and move the sticks. Don't use an Expanded-scale volt meter, just a plain old DVM (or better yet an analog volt meter) will do. See what that tells you.

        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 Pavlock
        Sent: Tuesday, July 04, 2006 3:58 PM
        To: NSRCA Discussion List
        Subject: [NSRCA-discussion] Analog Servo RF Masking and....Thanks!

        First I would like to thank everyone for the great advice on these last few posts I've posted. Everyone has been a big help.

        I'd like to ask if anyone knows if an analog servo would mask glitches coming in?
        (2 - Futaba 3010's, 2 - Hitec HS77's, 1 - HS81MG) 

        When I connect my JR digital servos ( 2 - 9411sa's, 1 - 8411sa, 1 - 8417, 1 - 3421sa) I get a pretty significant, constant glitch, as if the servos are constantly trying to center, but they have no load what so ever. This is the problem I have described in previous posts. 

        When I connect analog servos in an identical set up, there is no "noise" at all. I range tested them at 100 feet with 1 antenna section up and there is no loss in speed and no sluggish behavior. I also range tested this at about 300 feet with the antenna completely down just for kicks, and I get the same results. 

        When I range test the digital servos, even at the 100 foot range with the antenna completely extended there is a significant, constant glitch. The servos, receiver, and transmitter have all just gotten back from being checked and the 9411sa's had new pots put in, the receiver had been re-tuned to the frequency, and the transmitter got a new antenna. I am very surprised with these results as I just spent a fair amount of money to have my electronics looked at and deemed well. 

        Now, my question again, are my analog servos just masking a problem, or is this solely a problem in the digital servos?

        Thanks a ton everyone!

        Scott

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