2.4 GHz Radio FASST or DSM2

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Boris Mazor

Well-Known Member
Joined
Jun 13, 2006
Messages
547
Hi, Friends!

There is more then two system of 2.4 GHz radio. Did anybody know real difference in performance FASST Futaba and DSM2 Spectrum? Thanks. Boris
 
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yes, boris, spektrum 2.4 (regardless of version/dsm2 or 3) DOES NOT work well in boats. futaba fasst works very well in boats. this is from personal experience.
 
There is a huge difference. In being lazy I really do not want to write a book telling of the differences. However, this might help:

http://2.4gigahertz.com/faq/faq-fasst-q888.html

Futaba; Frequency Shifting spread spectrum technology, to learn more go to http://2.4gigahertz.com/index.html

Other; Frequency Hopping, which is being called "DSM", which stands for "direct sequence modulation". It is a hybrid of frequency hopping, which means it does not have follow all of Part 15 FCC regulations for frequency hopping.....

That is all I'm going to say except that "spread spectrum" is 2.4GHz. It is not a radio brand which I have heard it called many times:)

If you would like to learn more about Futaba, check out the corperate site at;

http://www.futaba.com/

Rw

Hi, Friends!There is more then two system of 2.4 GHz radio. Did anybody know real difference in performance FASST Futaba and DSM2 Spectrum? Thanks. Boris
 
Here's another Futaba site with an excellent history of the company.

<a href="http://www.futabahk.com.hk/asp/info/compan...file.asp?lang=1" target="_blank">http://www.futabahk.com.hk/asp/info/compan...file.asp?lang=1</a>

FWIW, I am using a 3PM FASST 2.4 system in 8 boats, 7 fast electric and a Insane gas cat. Flawless in every one.

A quick expansion on what Russ was saying is that there are three major methods of doing spread spectrum.

Futaba uses a dynamic frequency hopping scheme which changes the "channel" every 2 ms, or 500 times a second.

Spektrum Brand and JR use a system that selects two channels and locks on those. It will then switch between the two if one sees a high noise signal.

The third, used by XPS, locks a single channel and is supposed to hop if the noise floor gets above a certain level. Some testing has shown that it does not actually hop, but just slows down in response.

Here's a great spread spectrum reference:

http://cas.et.tudelft.nl/~glas/ssc/techn/

A little technical at times, but lots of good info.
 
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That is good info Bill. Just to be sure there is no confusion in the market, the "shifting" occurs every 2 milliseconds as indicated on our website. Hey, whats a ultra split of a nano second between boaters:) well.....it is no loss of signal:)

Also, the other does switch (hop) but only between the 2 channels it locked onto. "Hops" back and forth, does not "switch" within the spectrum.

Rw

Here's another Futaba site with an excellent history of the company.
<a href="http://www.futabahk.com.hk/asp/info/compan...file.asp?lang=1" target="_blank">http://www.futabahk.com.hk/asp/info/compan...file.asp?lang=1</a>

FWIW, I am using a 3PM FASST 2.4 system in 8 boats, 7 fast electric and a Insane gas cat. Flawless in every one.

A quick expansion on what Russ was saying is that there are three major methods of doing spread spectrum.

Futaba uses a dynamic frequency hopping scheme which changes the "channel" every 50 ms, or 500 times a second.

Spektrum Brand and JR use a system that selects two channels and locks on those. It will then switch between the two if one sees a high noise signal.

The third, used by XPS, locks a single channel and is supposed to hop if the noise floor gets above a certain level. Some testing has shown that it does not actually hop, but just slows down in response.

Here's a great spread spectrum reference:

http://cas.et.tudelft.nl/~glas/ssc/techn/

A little technical at times, but lots of good info.
 
That is good info Bill. Just to be sure there is no confusion in the market, the "shifting" occurs every 2 milliseconds as indicated on our website. Hey, whats a ultra split of a nano second between boaters:) well.....it is no loss of signal:)
Also, the other does switch (hop) but only between the 2 channels it locked onto. "Hops" back and forth, does not "switch" within the spectrum.

Rw
Fixed the 2 ms thing. Math error. That's why I am a geologist and not an engineer!!

And I thought Spektrum stayed on the one channel and only switched if it hit a noise floor. Thanks for the correction. I had been drinking when Diniz and Goldsmith tried to explain it to me!! They gave me a Spektrum hat too!! I wear it in the rain when I walk my dogs!! (kidding, I LOVE the JR guys!!).

So Spektrum is a "sort of hopping system". I'm OK with that!!
 
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I use XPS in boats ranging from nitro to gas to electric and have had ZERO problems. Most peolple come up and ask where my aerial is. XPS has an aerial about 1" long and does not protrude at all from the boat.

I have used this system over a few hundred metres without interuption or interference. That was after trying Spectrum1 and having only troubles.

Peter
 
I use XPS in boats ranging from nitro to gas to electric and have had ZERO problems. Most peolple come up and ask where my aerial is. XPS has an aerial about 1" long and does not protrude at all from the boat.I have used this system over a few hundred metres without interuption or interference. That was after trying Spectrum1 and having only troubles.

Peter
Please understand, I was not making a comment on how well XPS works. My comments were on the implementation of spread spectrum and the fact that at least three different tests have shown that the XPS system does not actually hop regardless of the noise floor. Simple facts, no judgment attached.
 
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