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spectrum pros and cons.

Old 08-18-2006, 03:35 PM
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Seek and Destroy
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Default RE: spectrum pros and cons.

How long is the reaction time in the spectrum?? How slow is it for the transmitter to move to where the car actually does it??
Old 08-18-2006, 06:21 PM
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Default RE: spectrum pros and cons.

Its only seems slow to those that buy into the hype of one brand being so much faster than others, in use I would say its not much of a problem. Been a lot of races won using some type of Spektrum system. As much as I like the Spektrum systems I think if anyone can pony up the added bucks to buy the brown box Nomadio special then that would be the way to go, unless you already have a high end module based radio and can just install the Spektrum module and receiver.

Ed M.
Old 08-18-2006, 08:17 PM
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rcxboy
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Default RE: spectrum pros and cons.

Think of it as you are already sinking $$$ into radio gear, that its hardly much more to pay to get nomadio.
Old 08-18-2006, 10:21 PM
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Default RE: spectrum pros and cons.

I talk to a LOT of retail dealers. Many have told me that they see upper-end to hard core racers moving back to higher-end crystal radios because of latency issues (That's good for me if true) with most all of the crystal-less radios. How much of this is hardcore truth? Is there a swing back to crystal radios for the racers that have the money to buy the fanciest. 'leading edge' technology gear? I'm not sure what to believe anymore!
Old 08-19-2006, 09:04 AM
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Default RE: spectrum pros and cons.

i have noticed alot of racers ditching the spektrum modules, however they dont switch to crystals. ussually they switch to synthysized modules.
Old 08-19-2006, 10:37 AM
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Default RE: spectrum pros and cons.

ORIGINAL: mkincy

i have noticed alot of racers ditching the spektrum modules, however they dont switch to crystals. ussually they switch to synthysized modules.
yea thats what i have been seeing, but ALLOT are switching to or have been using nomadio.

crystals dont have a delay but they can and do glitch, spektrum does have a delay, how do i know??? cause when i am racing i have to turn left before the actual turn!! if that isnt noticable, then i dont know what is.

a bud of mine races with the nomadio, prestine if you aks me, turns right on point.

you are right though, some people cant even know the difference, but i can and many others can as well. like what was said, if you are already sopping in 250 dollars on some radio, its well worth the extra 25 dollars to do it right the first time around.
Old 08-19-2006, 10:58 AM
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Default RE: spectrum pros and cons.

I just did my first run with my spectrum. It worked great and I didn't notice a delay. I was using it in my brushless 18t and it worked great, I didn't notice a delay at all, even though some people say there is, I didn't notice it.
Old 08-19-2006, 11:02 AM
  #33  
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Default RE: spectrum pros and cons.

I am gonna measure the latency on an oscilloscope. I will see if it is real or a misinformation campaign.
Old 08-19-2006, 11:07 AM
  #34  
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Default RE: spectrum pros and cons.

It's suppose to be 5.6 miliseconds or some thing like that,

and the pro version is 3.0 miliseconds.
Old 08-19-2006, 11:08 AM
  #35  
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Default RE: spectrum pros and cons.

Please let me know if you may need any assistance with this project. My plant in WI. sports just about any piece of HP test equipment you could dream of. We could dig into the stability of the oscillator circuits too.
ORIGINAL: rsilvers

I am gonna measure the latency on an oscilloscope. I will see if it is real or a misinformation campaign.
Old 08-19-2006, 11:27 AM
  #36  
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Default RE: spectrum pros and cons.

The 5.6 or 3.0 is just for part of the loop.

I plan to put a trigger voltage into the potentiometer on the DX3 steering wheel and then measure from the servo output on the receiver. I will repeat it with my X10 heli radio -- which is a very high end analog system. We will see what is faster and by how much.

SportCrystals,

I do need assiatance. I don't currently own a digital oscilloscope. I was actually planning to buy one JUST to stop speculation on what system is fastest. I am not sure what scope to buy and would ideally like to borrow one -- even one of those pocket digital scopes. I don't need a lot of bandwidth. Or you could do the experiment and report the results.
Old 08-19-2006, 11:50 AM
  #37  
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Default RE: spectrum pros and cons.

I think we may be able to help. Would you be willing to send your gear to our plant in Middleton, WI for such tests? I'll talk to my partner on Monday about this. It would be a fun project for him!

ORIGINAL: rsilvers

The 5.6 or 3.0 is just for part of the loop.

I plan to put a trigger voltage into the potentiometer on the DX3 steering wheel and then measure from the servo output on the receiver. I will repeat it with my X10 heli radio -- which is a very high end analog system. We will see what is faster and by how much.

SportCrystals,

I do need assiatance. I don't currently own a digital oscilloscope. I was actually planning to buy one JUST to stop speculation on what system is fastest. I am not sure what scope to buy and would ideally like to borrow one -- even one of those pocket digital scopes. I don't need a lot of bandwidth. Or you could do the experiment and report the results.
Old 08-19-2006, 11:56 AM
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Default RE: spectrum pros and cons.

Normally yes, except that I only got it this week. So I am playing with it every day.
Old 08-19-2006, 11:58 AM
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Default RE: spectrum pros and cons.

I'll let you know what my partner says about the testing. Your's is one radio we do not have at our plant.
ORIGINAL: rsilvers

Normally yes, except that I only got it this week. So I am playing with it every day.
Old 08-19-2006, 12:26 PM
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Default RE: spectrum pros and cons.

I have a Fluke 192B DSO. I may try this testing with my Nomadio if I get some time. I also have a crystal based CRX laying around here I can use for baseline.
Old 08-19-2006, 12:37 PM
  #41  
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Default RE: spectrum pros and cons.

Well if you get the test method working, then someone can get you a Spektrum and you can do all three.
Old 08-19-2006, 03:26 PM
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Default RE: spectrum pros and cons.

I have an M11 and it's "Extremely High Responce Technology" is just that... Extremely High Responce
Old 08-20-2006, 01:01 AM
  #43  
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Default RE: spectrum pros and cons.

Comparing a 10 channel to a 3 channel might not be a good idea. 10 channel has to sample all 10 channels and then send out and receive all that data.

A buggy traveling 20 mph travels how far in 5 milliseconds?

Ed M.
Old 08-20-2006, 10:56 AM
  #44  
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Default RE: spectrum pros and cons.

1.76 inches
Old 08-21-2006, 10:05 PM
  #45  
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Default RE: spectrum pros and cons.

I've read alot of good things and a spackling of some bad things with the Nomandio. I do like the Nomadio Sensor since it is a 2.4 GHz radio that was designed from the ground up.
I love the fact that is sofware upgradeable and it now has a 4th channel capability from simple a software upgrade!
I also love that the telemetry options are desigend into the receiver (excuse me, a TRANSCEIVER) as a single receiver and telemetry transmitter. The Spektrum has the fault of making your car or truck look like an octopus as well as the weight of a seperate telemetry module.
I would order me a Sensor, but the primary thing that holds me back is $$$!

I instead have scored great deals on 2 Futaba 3PK's. My 1st 3PK I got half off on a liquidation sale when a local RC store closed down. The second I got used from ebay. I got both for less than $175 each!
I also scored 2 DSM receivers (Spektrum) and one DSM module for 3PK all for less than $50! (As you probaly found out already, I'm pretty cheap, but I try to get the good stuff).
I have to program the 3PK's for PPM (normal FM setting) to use the DSM module, but I found out that Spektrum now makes a DSM module capable of HRS setting. I might give that a try I I can get some $$$ or find a great deal somewhere.
I have some trepidation about obtaining the telemetry package; I've heard too many bad things about them (the temnp gage doesn't work, the voltage reader is wrong, the RPM reader fails and does not always send speed, etc.).

But in all, my experience with 3PK and DSM module has been a good experience and I have'nt had any problems. I get what I expected out of the combo. A great radio and the benefits of 2.4GHz (no glitch, no crystals or even changing synth channels, etc.).
Old 08-21-2006, 10:35 PM
  #46  
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Default RE: spectrum pros and cons.

My temp gauge works, and my voltage display works. My RPM gauge needs some work, but I blame that on my mounting.

I have the Tektronix TDS-220 digital Oscilloscope now, and it is hooked up to my Spektrum receiver (the channel-3 output it connected to the scope's input-1). The scope's external trigger is connected to the transmitter channel-3 switch (which is generally used to shift gears). I will soon have latency data (how long an action on the transmitter takes to signal a servo to move).

I am doing this experiement because Nomado has been saying the Spektrum has a lot of latency, and I want to see if I should be concerned and switch to Nomadio.

For the record, Spektrum claims that their transmitter to receiver link is just 3ms latency (1/333 of a second). Nomadio has been saying that the Spektrum is really 15ms + 30 extra ms for your radio to do A/D conversion (1/22 second).

I am not sure if my results will show something about 3ms, or something about 45ms. I will post results soon.
Old 08-21-2006, 10:39 PM
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Default RE: spectrum pros and cons.

If you can, tell me more about the telemetry. Like I said, I've only heard about the bad things. I want telemetry but have not actually got it. As much info anyone can shed on its pros and cons would be greatly appreciated.
Old 08-21-2006, 10:44 PM
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Default RE: spectrum pros and cons.

I don't know much about it. I just got it this week. I set it up, and it works well, except I am getting flakey RPM readings. I am assuming that is because the optical sensor can see the three screws on my spur gear which are in the same path as the reflective dot. I have not tried to work around it yet. I plan to paint the screws flat black and see if that fixes it.

The lap counter seems to work also.
Old 08-21-2006, 10:47 PM
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Default RE: spectrum pros and cons.

Thanks! please post and let me know how it goes.
Old 12-31-2006, 07:02 PM
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Default RE: spectrum pros and cons.

Figured, I'd throw my two cents in....

I'm not a pro or anything close to it...but I've been in the hobby since the mid eighties. I just ordered my Spectrum DX 3.0 w/2 transceivers and ordered 2 additional transceivers (I have 4 cars that I will use with this radio). Now you are probably asking why not buy the Nomadio since cash wasn't an issue? For me it just doesn't make sense...I run electric and I'll probably never need the telemetry. If the telemetry technology could provide mph then I'd buy it just for giggles and to show non-believers that my "toy" electric car can hit speeds over 50mph. I guess the temperature sensor could come in handy for the batteries and brushless motors...but overheating hasn't been a problem for me yet....

Also I probably won't ever have more than four cars that I am seriously running at any given time. I like to keep it simple...I keep a large stock of spare parts for my cars because I am a basher...literally. Keeping my inventory down to two or three model types simplifies things considerably. I personally don't know why the RC radio market doesn't get into the habit of adding an SD memory card slot to newer radios...then we could store 4.0 gig worth of driver data....you telemetry nuts out there just think about that!!!! That would make it possible to record statistics from every run from every model separately! Then the guys that spend hours constructing the perfect batteries or tuning their motors/engines perfectly could really work wonders with the mounds and mounds of quantitative data. Me..and I am a stat guy...don't want to spend hours doing that...that is work...and this is my hobby. So I just buy the best batteries and motors and replace them when they no longer perform...and by the way...usually I use these forums to determine what is the "best." I am upgrading from a JR XR3i to the DX3.0 mainly to stop glitching caused by something in my neighbor's house...so in my case...the DX3.0 is the "best."

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