2.4GHZ ESC
 

Ok, silly question I am sure, but I saw a2.4GHZ version of the Novak GTB for sale today. I assume all speedo's etc work with 2.4GHZ anyway, they don't need a special version etc do they?

ye i seen these on dc racing site, and i think people thought i was mad when i said " has anyone seen these " i got the sorta reply like ... umm ye we know what a novak GTB looks like :eh?:

The Novak website has explained the benefits of the new 2.4Ghz/Spread Spektrum version of the GTB.

which is....??

The reason is that the conventional GTB has profiles to suit 40mhz. But I am told that the optimum frequency for brushless actually interferes with 40mhz so isn't included.

But the Spektrum version, that has the better profiles, the ones that 'may' cause interference with 40mhz, but it won't with Spektrum.

I know of someone using one for Spektrum in a non spektrum car, and its been working fine.

I am using the none-spektrum GTB, only because thats what i got as I wasn't running spektrum when I got it, am now tho.

is it just me who got totally confused there? :p

[quote=Chrislong;65284]

I know of someone using one for Spektrum in a non spektrum car, and its been working fine.
quote]

it was working fine untill i stuck a knacked trakpower lipo in with it and it went with a small cloud of smoke to a fine resting place.

Sly

I use the Spektrum Novak GTB.

In basic terms (for Jimmy :p) the Spread Spektrum GTB operates at a higher frequency than the GTB.

This higher frequency smooths out the performance of the brushless motors. The reason it is specified for Spread Spektrum is that it can interfere with conventional radio waves ie. 40mhz FM. however 2.4Ghz Spread Spektrum is not effected by the higher frequency pumped out by the Spread Spektrum GTB.

PS. When I have had to run the spread Spektrum GTB with 40mhz I do get occasional glitching when on power, which does seem worse when using my better packs of batteries.

novak says not to use SS GTB with crystals. i.e should only be used with 2.4

So we know that the SS GTB can interfere with the reception of a 40mhz receiver in the same car........

Does Novak guarantee that it will not interfere with the reception of our fellow racers cars who may be using 40mhz??

It would seem to me that during an overtaking maneuver cars can get pretty close and could be subject to glitching while doing so.

Personally I would like to see some documented evidence detailing testing to show Novak put a good deal of thought into this!

I could not see any evidence of this on the website.

:rolleyes:

Have you heard anyone actualy complaining of this???

And would that be any different to someone running a poorly maintained brushed motor that's giving out loads of noise when someone tries to overtake?

The electrical noise that Craig is talking about is coupled into the receiver along the wires, not through air.

Most electronic devices require EMC test, of which one test is for 'radiated noise'. Not sure if speedos need to though.

G

If the inerference is simply conducted down the wires then clearly there would not be an issue.

However since we are talking about high power high frequency switching I did not think it was too unreasonable to speculate that the interference may be radiated form the power wires.

I guess that if the system has been tested for electromagnetic emmissions then it should be fine for use.

It is early days, and i know of only one individual who has recently purchased an SS GTB at our club. If this starts to cause other racers problems we will have to consider not allowing them to be run. If there is an issue I would assume others would also notice in the fullness of time.

Dan... Simply hypothetical at this stage.

:)

I will be the first to admit I'm not an electronics expert. However I am really struggling to see what can possibly be different between this system and the standard.

Aren't brushless ESC's just synchronous supplies? Unlike the the fixed frequency stepping in brushed ESC, the frequency of a brushless ESC would vary, and would have to match that of the motors rotation per second (rps). For a typical rc car scenario, say a motor of 7000kv, that's 50,000 rpm roughly, so 850rps ish. Therefore using the 2 pole 3 phase system would the output not be just in the region of 2.2kHz?

Way below even standard crystal radios, let alone 2.4GHz systems!

Hopefully someone can clear this up for me, as I'm confused!

Does anyone know weather the type of frequencies that Mr Long has explained cause interferance on a LRP sphere comp 2007 using a spektrum system or does the LRP run a totally different set of frequencies and there is no interference problems?
Cheers Si.