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

Wed Jul 5 08:04:43 AKDT 2006

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 <jpavlick at idseng.com>
>
> *To:* NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
>
> *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 <f3aflyer7 at gmail.com>
>
> *To:* NSRCA Mailing List <nsrca-discussion at lists.nsrca.org>
>
> *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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>
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