felker14

My Feedback: (50)

Where can you by the Emcotec power box?

Kris^

My Feedback: (1)

Okay .. back to work on this subject. . I HATE going to work every day. . just ruins my RC time.

I had both planes at the field this weekend, and halfway through the day the Powerbus 40-24 proved it's worth. I was looking through the canopy, preparing for a flight, and wanted to see what the LED readouts said about the voltage levels. Only ONE side was working!!!

Off came the canopy, and I started probing around, only to find that one of the difficult-to-solder HD Deans plugs had a broken solder joint (my own fault, too cold apparently), and I had been flying on only one battery!! The "good" side of the box showed 1 LED down form maxed out, the other side was dark, indicating that I had NO battery voltage on that side due to the disconnected Deans plug. Yet the plane behaved normally, and had flown as it always does.

JUST to try it out, and see what happened (Okay, shoot me next time I try this with a $6000 model) I took off anyway, and flew two of the Advanced sequences for this years IMAC. The plane flew perfectly, as if it had both packs on line. After landing the voltage level had dropped into the "yellow" area, about 6-6.1 volts or so, so I decided to call it a day with that plane. So, in this instance the Powerbus 40-24 had saved me from my own ineptitude, and thanks to a quick glance at the voltage indicators on the box had probably saved me from a very bad crash due to battery voltage failure. This makes the $325 investment a VERY good one, even if it only saves the plane once.

To be fair, I tried disconnecting one of the battery packs from the Emcotec box in the other plane, and instantly got a VERY loud and bothersome alarm sequence beeping its heart out from the Emcotec box. So, either way, visually or audibly, my planes are protected from low-voltage if I only pay attention to the indications.

Back to the Powerbus, though. I got home, cut the Deans plugs out of the wiring harness, and soldered in some "Zero-Loss" connectors instead. These are much easier to solder, and are extremely heavy duty, having the same conductivity as a 13-gauge wire, or about 80-100 amps per plug. After this fix, I started going over voltage levels and signals. The accompanying picture shows the in-out signals on the Throttle channel, taken directly off the Powerbus 40-24's leads. Again, as with the Emcotec unit, no real amplification is taking place, but there does appear to be some filtering through a circuit that would prevent feedback to the receiver. Unlike the Emcotec, though, the only regulated voltage from the 40-24 box was to the Receiver, and was a rock-solid and steady 5.05 volts. You can see the results of the lack of "regulation" in the signals in the picture, with the on/off of the digital servos being fed back along the common ground of the unit. The signal is much "dirtier" than the signal pictured in the post for the Emcotec box. Voltage to the servos, remember, is not regulated, and they get whatever voltage level the battery packs fed them, which means any changes in "ground" are seen throughout the entire circuit, and are not isolated.

I did a comparison of the input voltages and what voltage level was actually being fed to the servos. I used one fully charged pack, and a slightly drained one. Until the packs equalized, the voltage going to the servos was within .05 vdc of the higher input voltage, and after the packs equalized all three voltages (two inputs, one output) were all held within .1 volts of eachother, lending credence to the claim that the box "balanced" the packs drain rate so that the voltages stayed equivalent throughout the charge reduction. Doing the "Snap" test, as I had with the Emcotec box, showed that the voltages in and out of the Powerbus 40-24 were basically exactly the same, no matter what the load was at the time. Oscilloscope traces revealed perfectly duplicated traces between the input and output voltages, with concurrent "Up" and "Down" spikes.

As for setup and installation of the Powerbus, it's a bit less involved than the Emcotec unit, but the output sockets are on the top of the unit, not the side, making a "neat" wiring installationa bit more difficult, though the wiring is much easier to reach. The six "Receiver side" leads are hard-soldered in place, and come with ferrite rings to prevent RF interference feedback on the wiries to the receiver. So, in this case, what you wind up with is 6 leads in, and up to 24 servos plugged into the box for the output.

I consider the Powerbus 40-24 to be a much more rudimentary unit, in this comparison, though the features it has are going to cover about 98% of modelers needs, and the capabilities of the box will handle just about any aircraft out there. For the money, the 40-24 is a good unit, and it's upgraded siblings (Competition Series boxes) Have an additional channel and better voltage level controls. All three, once you buy switches for the "Professional" box, are approximately the same price, at about $325 before shipping.

Richi-d

You should add this fact to your post: The Powerbox you tested is the model from 2001 - the Emcotec is a 2004!! There is a new Powerbox 40/24 Professional available for 3 month. It has 7 channels, a new pulse amplifing and a "low-voltage memory" - for the same price!

I wrote it down in a lot of posts: the ferrite rings are not for reducing interferences!! They are for decoupling the ground! If you plug in a lot of cables (and a lot of servos) to a receiver and don´t decouple the ground, you get a loss of RX range!! Other products don´t have this feature cause it´s costly!!
The pulse amplifiers are better for decoupling interferences!!

If you want to have exactly and more data ask me - your welcome!

Kris^

My Feedback: (1)

Unfortunatley, Richi, you have not supplied me with one of the new 40-24's to compare with the Emcotec box, so any "Claims" are just that. . claims, not a review. As for "ground decoupling", I'm sorry, that does not wash. You can't decouple the ground, since these units utilize a COMMON ground, as evidenced in the extremely dirty Ground in the picture of the signal trace of the 40-24 I am looking over. "Feedback" is plainly visible in that picture, on the zero-voltage/ground potential level, and transfers directly into the DC voltage levels shown on the trace. The Emcotec unit, however, with voltage regulation on the servo side, appears to better isolate these inconsistencies. Ferrite rings have long been used to damp unwanted RF feedback, with several windings of the servo lead through a ferrite ring providing a "choke" for unwanted stray signals, spike, and anomalies that feed back to receivers, and they serve the same purpose in this instance, otherwise they would not be present. In this case, however, the rings do not stop the pulsed DC from the digital servos cycling on/off, and the frequency of these pulses is the same as the refresh rate of the HiTec digital servos being used in the plane. Obviously, at least one of the servos is feeding back some signal along the ground wire, and even the Ferrite "chokes" are not removing it, probably because the frequency is too low.

Please note that the Emcotec unit does not NEED the Ferrite rings on the receiver side wiring, nor is it even mentioned as an add-on for the unit.

It will be interesting to see if the "new and improved" 40-24 (still with only 7 channels compared to the Emcotecs 12) will live up to all the hype. In the meantime this review will continue with the units I have on hand, since the basic functionality of the Powerbus 40-24 is the same as it's siblings, and any differences among the Powerbus 40-24 units are being noted in detail as this is written.

One note, concerning pricing. . . When I purchased this "2001" 40-24 unit in May of 2003 (I guess this makes it a 2003 unit, doesn't it???) I was quoted $250 for the unit and a further $70 for the switch setup. That's US DOLLARS. The purchase was applied to my credit card in EUROS, not Dollars, raising the price by about 25%, in effect changing what I paid from $320 USD to about $400 simply because of the way the sale was charged to my credit card. I guess, in this case, you do not get what you paid for. I'm also pretty sure that this was not a case of a language barrier. . .

It would be germaine to point out, as well, that the Powerbus 40-24 I bought directly from Mr. Deutsch at Joe Nall last year FAILED the first time it was installed. The power leads were plugged in and one entire side of the LED readout went defunct immediately. The unit was replaced, no questions asked, by Gerhard at Aircrat International (Thanks Gerhard, I do appreciate it)

Richi-d

The rings decouple the ground - fact!! They don´t decouple the ground for DC - but for 35 - 72 Mhz it does! This is RF-technologie not DC! Little bit more complicate...
The Powerboxes only have 7 channels, because if you plug in all servos to an extern Powerbus, you shift the tuning for the receiver -> same problem like you connect all servos to the receiver -> less range!
The receivers have their optimal tuning for the amount of servos you can plug in! Not for Y´s or anything else. So the perfect setup is 1 - 5 servos to receiver, rest to Powerbox. I think for most of planes 7 channels are more than enough: 2 elevator, 1 rudder, 2 roll -- this are 5!

Again: It´s cheaper to make a powerbus with 12 or 30 channels than to build in ferrite rings! This is the reason competitors don´t use them!

I don´t know anything of a failing Powerbox - exept one which polarity of the battery was plugged in false of it´s user

Kris^

My Feedback: (1)

Richi, really now. . "decoupling" that does not occur on a DC circuit is useless for a DC power circuit. Since the "Ferrite Rings" are being utilized to "choke" a certain set of high-frequencies, in this case 35-72 mhz (which is basically impossible to accurately predict with a hand-wound/non-tuned setup such as this box uses), it is only useful IF you are getting interference ON these frequencies to begin with, and if that interference is close enough to the receivers tuned frequency to actually cause a problem. Considering that the receivers rejection circuitry already tunes to a 10khz window, the necessity to "decouple" the leads to the Receiver is literally non-existent. As well, "rejecting' other frequencies is a non-issue with a properly tuned and aligned receiver in the first place. So, really, the entire "Ferrite ring" argument is a non-issue. They are not tuned, are hapharzardly wound, and really offer no improvement over the rejection and tuned circuitry already incorporated in the receivers. Simply twisting the wires, at 1 twist/2-3 inches of length, would have the same effect, and effectively "decouple" RF frequency interference due to the inductive shield created by the twisted wires. We DO twist our wires, don't we?? (I sure do)

What IS necessary, however, is to damp and eliminate very strong RF interference in the 15-150 hz range, such as would be experienced form a bad ignition, or in the 250-1500 hz range, for the type of interference that would normally be associated with a Turbine. THESE sources of interference, and their secondary and tertiary harmonics, are THE major source of jamming in most aircraft, since the wattage levels from these sorts of interference can be VERY high, and they are in very close proximity to the receivers.

From your statement concerning the "optimal tuning" of receivers, where you stipulate that they are "tuned" to stay on frequency for a set number of servos at a certain load, and straying from that would be detrimental (at least that's what it sure sounds like you said). Consider this, then, an 8-channel receiver with TWO servos per channel . . .Is this going to somehow "load" the receiver so that it loses proper sensitivity and wanders off frequency? I daresay it won't. . How about that same 8-channel receiver with only 2 servos? Is it now going to somehow be better than if 8 servoes were plugged in? and what of the difference in 4,6,8,10 or even 14-20 channel receivers? I guess, if what you say is true, an 8-channel receiver, using only 5 servos, would have a substantially longer range, and more sensitivity, than the same receiver plugged into 12-14 servos. I have in fact experimented with just this sort of setup, using an external buss bar setup so that the power for the servos did not go through the Receivers on-board buss lands, and had 15 servos, on 5 channels, plugged in and working flawlessly. By taking only the signal from each receivers port, and splicing that signal to 3-4 connectors, then using external power feeds to the plugs for the servos, I was literally running 3-4 servos/channel, with common ground for the entire setup, as well as common voltage. No Glitches, no loss of range, and no problems at all. This would support that multiple servo setups need not really worry about degrading Receiver capabilities. The question has to be asked. Why would it be necessary to use "ferrite rings" to "decouple" the receiver from the powerbus 40-24 units? Taking a look at the basics, there should not need to be anything at all done to ensure against feedback of this sort. Perhaps there is a problem, before now not brought to light, that needs to be addressed in this fashion. If there is, I am unaware of it, since the FIRST thing I did when I installed my Powerbus 40-24 was to remove all those little ferrite rings. There have been no complications (except for the first failure) since that time.

Overall I've been happy with my Powerbus 40-24. It's not a "feature loaded" piece of bells and whistles, but a good, basic, dependable centralized power source for my servos, which is all I require or desire. It's not regulated, except to the receiver, and handles the servo count I need for the aircraft it is installed in. To SAY that it is much more than that is disingenuous. To claim that it is somehow "superior" is in fact an intentionally misinformative statement. It does what it does, it's siblings have more "features" and capabilities, but in the end they all do pretty much the same thing, supplying power, at a regulated level for the "higher end" units, filtering feedback to the receiver, and giving the modeler a really pretty "Thing" in theplane to brag about. That's what they do, and trying to make them to be more than that is not doing them, or the end-user, justice.