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Just wondering if any one has any info on these items:

I see Novak is advertising new GTB's with "Spread Spectrrum Technology."
Does this mean they will ONLY work with SST radios, or just that they preform better with SST radios? Will they still work with FM, etc?

Anyone have any idea when the new Novak GTB 4 cell and 13.5 Pro Stock combo #3043 (or any of the new GTB Pro combos) will be available?

Thanks!
 

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Maxxratter said:
Just wondering if any one has any info on these items:

I see Novak is advertising new GTB's with "Spread Spectrrum Technology."
Does this mean they will ONLY work with SST radios, or just that they preform better with SST radios? Will they still work with FM, etc?

Anyone have any idea when the new Novak GTB 4 cell and 13.5 Pro Stock combo #3043 (or any of the new GTB Pro combos) will be available?

Thanks!
The new GTB/SS Pro systems will be shipping to distributors this week.

The #1711 GTB Spread Spectrum Brushless/Brush ESC and the #1715 GTB 4-Cell Spread Spectrum Brushless/Brush ESC are for use only with Spread Spectrum radio systems (2.4GHz radio systems).

http://www.teamnovak.com/products/esc/gtb_spread_spectrum/index.html
 

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The material is a heat transfer material. Sort of like the white heat sink compound that you get from Radio Shack but much better.
 

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Are there companies out there that make a replacement top heat sink or can it be removed for 4 cell 13.5 racing ??
 

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If you are running 4 cell 13.5 you won't need a heat sink. 13.5 motors are a very low power motor and low amp draw so heat won't be an isssue. We run 4 cell 4300 and 5800 w/o heatsinks and they run fine. Temps on the speedo are around 100 for a 5800 and less than 90 for a 4300.
 

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The 2.4ghz based radios (Spektrum, Nomadio and Futaba's 2.4) can use the new GTB's higher drive frequency they are more efficient but may cause glitching with the old style FM and AM radios. The regular GTB's 4 cell and the orginal one operate at a lower frequency to eliminate the glitching issue. If you are looking for a speed advatage with the newer speedo it is highly unlikely. More efficient is less heat but in reality heating is not an issue for 4 cell but if you run 6 cell mod 3.5 and up you may have a cooler esc at the end of a race.
 

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My fairly new GTB just puffed alot of white smoke. Anyone else have a GTB go bad under normal use? I just run 13.5T and the ESC went bad right after I taped my batteries in, connected the plug to the battery and flipped the ESC on.
 

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From experiance, if you get 4 runs out of a GTB or the LRP with no issues you have a good one, if not, its got to go back as bad for replacement.
 

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Will it mess up other cars on the track using crystals?

Regardless I am not convinced that generating RF is a good thing or required to achieve performance. Yes switching fast can reduce heat, but good fets switch plenty fast without generating RF if done right. It is not as simple as fast=RF. It is a combination of things that cause it and it can always be filtered out with a little money and effort.

Novak should be embarrassed that they could not keep their unit from thermal shutdown without generating so much RF that a crystal radio does not work well, and then telling us that this is a neat new feature.

Sorry, but we put up with so much bull in marketing and I am simply disappointed and insulted by this promo angle. I have always liked Novak products but this is not good engineering. Bugs me enough I did my first posts on several forums.
 

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Factoid? (Interesting choice of names) Two posts? Did you sign up just to bash NOVAK? Novak is just leading the way again as they have in Brushless from the start for RC Oval. More and more people are switching to Spektrum technology and they see some advantages of the system to be used so they are pursuing it, no other manufacturer is advancing the tech as far as I can see. Kudos to NOVAK, hopefully some people will stop bashing brushless in any form and either get on the bandwagon or just quit the hobby and leave the rest of us in peace. My .02 Ralf
 

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Been reading for years, finally bugged enough by something to get involved. We all had to do our first post somewhere and had a reason that motivated us.

Bashing? The guy above me is bashing with an unsupported personal opinion. I am stating the fact that this is a design problem that marketing is claiming as a sales feature. I love brushless, but do not like seeing one of the most respected companies in the industry market like a bogus claims infomercial.

What exactly is the advantage? "Does not provide any noticeable performance difference", claimed in their own press release. "Does make the esc slightly cooler", which would not matter if it is was not problem to begin with. Why accept a negative like RF noise unless there is an advantage to offset it? Show me a good design engineer that will say anything different. Prior to this press release Spectrum Optimized would have meant broken to most of us and now it is a good thing?

Like I said I have always liked Novak products, but this is insulting. Blind loyalty just makes you one of the sheep they are counting on. We will see if any other company offers a Spectrum optimized system or should I say is forced to.
 

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The "new and improved" sticker on the latest electronic gear has always played to the oval racer. Go back to the 90's and Tekin made new speed controllers about every 6 months. Same case with a different sticker. But some how it was better. They ran cooler or recharged the batteries when you were off the throttle etc, etc. Novak and Epic and Yokomo made new esc's and motors claiming more power and better this and the like. You didn't here the complaints then. Technology has always going to advance and it is going to cost you money.


Do you really need a broad spectrum radio to be fast, no but it is really convienient to have it though. At times the new stuff has its advantages but it also has drawbacks due to the cost.


I think that we need to be open to the new stuff but to also keep and eye on performance too. I do not envy anyone who wishes to get started in today's R/C due to the different choices of what to race and what to buy. The fact is brushed motors are going to be extinict for racing soon and new battery technology will surpass the NIMH and Li-Po packs as well.
 

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Well seeing as theses units are just out and no one knows exactly there performance so there is little fact at this point on the new unit. I just got the shipping notification for my unit and was worth the extra $20 if it even runs a little cooler. Why? Running 4WD buggy we create a lot of heat and in the summer on hot days it can be iffy if you can keep any motor cool. Cool motor = performance. So a little more cooling adds to motor life and performance on the track. That’s why I went for it.

Brushed motors and AM/FM radios for racing are heading the way of 8-track. Yep, there not going away, but other than RTR and other low end setups, there on the way out.
 

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Adnan Khan (Novak Electronics) GTB Spread Spectrum

Over the years, the Mosfets used in Novak's ESCs have steadily gotten better and now we have reached a point of diminishing returns as far as the Rds On of the Mosfet is concerned. The GTB uses Mosfets that have a Rds On of 1.2 milli ohm. The PCB and wires have much higher resistance than the Mosfets, so why does the ESC still get hot? That is because most of the heat is caused by the switching losses and not the Rds loss.

In an ideal situation, we would like to see zero switching rise and fall times. Fast rise and fall times cause large current spikes and produce lots of radio frequency interference. In a power supply or piece of industrial equipment, typically the manufacturer encloses the power section in a steel box and uses a large ferrite core to reduce the RFI noise. We don’t have that option!

In the GTB design we have had to slow the rise and fall time significantly so that it would work with ALL the radios out in the field (slowing the switching rate brings the noise floor down by 30-35 dbm). Compared to other high performance ESCs out in the field, the GTB has the fastest switching rate as we use 6 layer power PCBs with lots of ground plane and high frequency capacitors to de-couple noise.

Slowing down the switching rate causes more heating because the Mosfets are in the linear region of operation for longer periods and that accounts for most of the heating in the ESC. Also as you slow the switching rate, the pulse width driving the Mosfets starts to look like a trapezoidal wave form instead of a square wave and that causes the trigger control resolution to go down.

The last issue is that the dead time between the electronic commutation required goes up as we have to wait for one bank of Mosfet to turn off before we can turn on the next bank. In our Brushless ESCs we have six commutation steps per revolution, so any improvement in dead time reduction and switching efficiency can be significant.

The Spectrum optimized GTB uses a very fast Mosfet drive circuit switching speed (in the order of 1uS or less) and that will translate into significant improvement in efficiency under high loads and much smoother throttle response. We at Novak are committed to bringing the best possible racing Brushless system out to market and we are continually pushing the envelope of technology. Spread Spectrum allows us to improve the system performance without affecting the radio performance.

One last note on the fast switching ESC: it does not interfere with the radios outside of the car, so you will not be causing interference to the car next to yours whose user has the traditional crystal radio.
 

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Hmmm... what happened to Factoid :confused: Sounds like Novak stepped up to the plate and responded to his posts with technical answers... I am waiting to read his responce ;)
 

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Adnan,
Thanks for clearing all that up. Nice to see you drop in here and fill us in on the new design. Now I'm just waiting for mine to arrive. It is going into a 4WD that runs on soft dirt tracks so it is under load a lot, so this new setup will help.
 

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Easy boys, some of us have a life beyond being a forum rat. I started this and do not need any coaxing to finish up.

Thank you MR. Khan for taking the time to explain this in detail. It is text book engineering and exactly what the press released claims with more detail and maybe a few unintended admissions. I agree with almost all of it and I have to say you made my case for me nicely.

I can accept that you had to increase switching speed to the point that there are problems with crystal radios because the unit cannot handle the heavy loads and overheats even with a heat sink and a fan. I guess for marketing purposes that had to be shortened to ‘Spectrum Optimized’. Otherwise it really does not have that ‘I gotta have it’ ring to it.

If it truly makes the unit considerably better, then perhaps the trade off is worth it. If it simply makes it work then I still say it is a Spectrum Bandaid and a marketing spin.

Some may argue that the GTB did not have thermal problems to begin with. I suggest you search the word ‘Thermal’ in the 60 pages on Rctech in the electric onroad section ‘New Novak Brushless system’. It is not like it is a secret that it has been an issue.

I think you should check out the competition a little closer. Many products are switching much faster than you mention. I believe the Castle unit switches in less than 100ns or 10 times faster and so does the Quark unit. I see Tekin does not even have a heatsink on their new unit so they must also be switching pretty fast to pull that off. Somehow they all controlled the RF and do not require the use of 2.4Ghz radio.

Now that it has been explained (admitted) that RF and heat could not be controlled at the same time for some reason in this circuit I will leave it be. At least that is better than a creative marketing angle to cover up a design problem. However for those in the know I have to say you have lost your position as the technology leader and then tried to tell us it was a good thing and we should be excited about it.
 
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