xp8103

My Feedback: (16)

Ok.... Here's my $.02. Two 5645's plugged into two 10" 22ga. extensions to reach my Expert reveresing Y, plugged into a JR 950 SPCM Rx, 1500 6v pack. Servos work perfect. No jittering, no noise, no farts.

embpic1

Ok. There is an interesting thing going on with these reversible Y harnesses. I have read the previous post about problems with the reversible y. I have also read two posts from people who use the Expert reversible y and the digitals with no problem. I just bought 4 5625s and used an Expert reversible y for my elevators. I have them on my 1/4 cap 232. I put about 15 flights on it with some pretty hard flying. I had no problems at all. ATV is set at 120%. My point is that maybe the Expert reversible y is compatible with the Hitec digitals.

Sean

Kris^

My Feedback: (1)

First off. . I have to say this is one of the BEST threads i have ever read. . Kudoes to all participants. I've been using the HiTec digitals since they were first available, and have never looked back.

In my personal experience I have had two instances of HiTec digitals interfering with eachother, one being so severe that the entire aircraft was going into PCM lock on an intermittent basis due to one servos problems/feedback. The problem only occured, though, when a 5735 (3-pole motor) and 5945 (coreless) were used together on the ailerons, two servos per side. I found that the 5945 was 'glitching" the entire radio setup whenever it wanted to, basically feeding back enough interference on the ground side to blanket the receivers circuits.

That particular servo was returned, but checked out okay on the HiTec Service center check. I've used it since, with no problems, but I keep it away from 5735's now

I always run 5-cell setups, direct-wire my power and ground leads to a proprietary buss-bar setup instead of running them through the receiver, and use signal only out of the receiver going to the servos. So, when I was aligning a new gang of 5945's last week, matching them with an un-amplified "Y" off the programmer, it bothered me a LOT when one of them stopped working on a consitent basis. Basically the servo would jerk it's way through the movement range instead of moving slowly and smoothly. by itself it would work fine, but the moment another servo was added it began to glitch again. I continued to test and re-test the servos, to make sure I had not gotten another "bad" one, and sure enough, another servo began to glitch as well.

I was really getting bothered by this. . then suddenly EVERYTHING stopped working. . . . . OOPSIE, the battery had gone low on the programmer (4-cells) and that is what was causing the "glitches". After a re-charge every servo worked fine again. . which just shows how important having adequate voltage and wiring can be toward these servos working properly.

I've run 5 different types of JR receivers, and both old and new Airtronics PCM receivers, 2 -4 servos "y"d together, and it's always been a voltage/power delivery problem that has caused marginal results with my HiTec servos. Now that the VERY technical efforts of the people on this thread have come to light, it will be even easier to isolate any future problems. (who would have thought that the signal wire was bi-directional??. . .not something you expect to see)

Thanks again for the great thread, guys. . it really made my day reading it.

Forgues Research

My Feedback: (7)

About 5 weeks ago, I ordered some of Rogers "Fiber optic extensions" from him,
to be put into a plane I am preparing for a rather noteworthy person (who shall
remain anonymous since this is supposed to be a SURPRISE for him). I REQUESTED
(yes, my initiative) 7 sets, with the stipulation that I would get my money back
if they were NOT up to my expectations. These 7 sets would cover every channel
and set of servos in the plane.

The first thing I did upon receiving the fiber optic Extensions was to hook one
up inside my DR109, and test its signal isolation using the rather defunct HiTec
digital servo that I referred to in prior posts to this list as having the
ability to shut down a receiver with feedback and interference. The fiber optic
Extension used its own power source, an 800 Mah 5-cell pack in the case of this
test, totally isolating itself and the servos on its output side from the
receivers power and signal wires on the input side of the isolator. Using the
isolator, I had ZERO cases of interference over a half hour period of testing
range on the receiver, and it was actually slightly more sensitive than the
other receiver in the plane, showing fewer cases of PCM lockout at the limit of
range. Then I hooked the servo up to the receiver in the normal fashion.
Immediately the receiver started going into failsafe in a sporadic manner. I
swapped the servo back and forth a few times to double check the isolator
vs. receiver setups, and never had a problem with the isolator setup, where as
the direct receiver link always had a problem.

Then I hooked up a few "Y" cables to the output side of the isolator, ganging together
3 5735's two 5945's (including the "bad' servo) and 2 805 Hitecs and monitored
them for feedback or signal problems. None seemed to cause interference or
glitches with the others, even when moved rapidly back and forth by slamming the
stick on the transmitter between max throws on high rate. To me, this showed
the isolators capacity for handling large instantaneous current loads as the
servos started moving or reversed directions. It's not the most scientific of
testing, with meters and scopes and digital recorders of data, but as a good
Field Test, it shows a lot to the discerning mind.

Now, the way the Fiber Optic Extensions are set up is that they use a remote
Optical emitter and receptor setup, with a connecting fiber optic cable, and the
receptor uses a proprietary battery source, separate from the Radio Receivers
power, to power the servos attached to it. I wound up with one 1100 mah
receiver battery, two 2700 mah servo packs (one for each side of the plane) and
an ignition pack of 2150 Mah. That's 4 switches and charge jacks on a 40+%
plane, and a 5th switch/jack if I ran dual receivers. I also had to run
discrete power to the tail for the elevator servos, one pair of wires per side,
along with 2 optical receptors and associated fiber optic cable. I could have
run a single unit in the tail, to control all 4 servos, but I wanted the
redundancy of splitting the elevator halves in case I lost a battery pack on one
side.

Things I liked about the setup: It's very easy to set length on the fiber optic
cables, either wrap them up in a roll or cut to the exact length you desire
(using scissors), the total isolation of battery source from the receiver works
very well and totally isolates ANY interference from outside sources unless the
receiver antenna picks it up, you can place the fiber Optic receptors anywhere
you want inside the aircraft, up to 4 feet from the emitters, which means that
aft of the tail post or ahead of the engine is within easy reach, and being that
you use a separate Isolator pair for each channel, versus having a 4 or 6-in-1
unit such as the Jomar or Electrodynamics units if you ever have a failure of
ONE unit, you simply replace that part, not the entire unit (as you would have
to in the case of the Jomar designed piece). Also, since you have a long fiber
optic cable, instead of an actual wire, running to each servo or set of servos,
there is less chance of picking up stray signals/interference that might degrade
servo performance.

Yes, you still have the two power wires, but the elimination of the signal "wire"
for most of along distance eliminates the possibility of having a signal wire-to-positive
or negative wire short in the bundle (such as if rubbed against a screw or sharp
object that you did not know was there), which can cause the servo to lock in
one direction.

As for "WOW" factor, I took the fuselage to my last club meeting, with all the
fiber optic pieces in place. . guys were very impressed with the setup and
optical cables run right alongside the wiring inside the plane, and I got a lot
of questions about it. I gave a short demonstration, showing how the
performance was in fact better in questionable situations where high amounts of
interference were present (using my trusty "feedback" servo) while using the
Fiber Optic pieces.

As for myself, I'm sold on them. . there are alternatives to the "discrete"
setup, and they work just as well, but to ME (and me only) it just makes more
sense to have discrete units for each channel, and to be able to place them
wherever you want. this way, there is no chance of total failure of all
associated channels as there would be in the case of a "hub" designed isolator.

Best regards

Kris
Here is what a Large Scale Aerobatic pilot "Kris Welter" had to say about the Fiber Optic servo extensions

johan_torssell

Any news on connecting two Hitec digitals via a Y-lead to a Multiplex IPD receiver?