RunRyder - Spektrum receiver/transmitter modules for flying

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Radio - JR & Spektrum DSM > Spektrum receiver/transmitter modules for flying

kintave
Heliman
Location: Ann Arbor, MI

Hi there,

Any word on Spektrum making modules for futaba and jr flight radios?

They are just starting to come out with modules on the ground and water. No frequency worries anymore or changing of crystals for those guys as the module locks in to the frequency and prevents any interference.

Heard it will work awesome.

03-06-2005 Over year old.

kintave
Heliman
Location: Ann Arbor, MI

http://www.spektrumrc.com/DSM/Default.html

This is what I'm talking about. Maybe the FCC and AMA should rethink their position. Much more secure form of transmission.

03-06-2005 Over year old.

onemetre
Senior Heliman
Location: Mansfield, Tx - USA

I would expect FCC and AMA would have been consulted and be knowledgeable when the spektrum systems are sold for air use. If it all works Futaba would loose alot of market share if they said their stuff couldn't use spektrum equipment.

When it happens any module based radio will be able to have 4096 resolution which is 2 times the resolution of the brand new 14MZ that is $2000+.

Rob

03-06-2005 Over year old.

bjacks
Veteran
Location: Ft. Worth, Tex.

Spektrum

Spektrum modules are Certified with FCC, there made for KO, Airtronics, Futaba, and JR, ground only so far, one of best thing to come out in a long time. Bobby

03-06-2005 Over year old.

RCHeliJim
Key Veteran
Location: Orem, UT USA

Well, the AMA, Futaba, etc will need to grow up and accept it then. The FCC approved it for ground use - IN OTHER MANUFACTURERS RADIOS - because they dont offer a radio themselves. And all the governing bodies for on-road groups have accepted it (ROAR, etc) I am sure the FCC knows and understands that this is the deal, so I would not consider them a problem.

So when the technology is available, the AMA would only need to make a slight constitution or rule change, and BOOM, there we go.

I for one look very forward to it, and the end of the frequency board as we know it

No more lockouts caused by other radios sounds like the safest thing to ever happen to our control systems

Go Fly, Have Fun!!
-Team Quick UK
-Team RCHeliMag

03-06-2005 Over year old.

HOMEPAGE

Angelos
Key Veteran
Location: nr Oxford, OX11, UK

Such modules have their own antennal and they don’t feed their RF signal though the transmitter. This means that they can be type approved by themselves. They only plug on the TX module socket is just to received the PPM signal and power from the transmitter.

[QUIOTE]
When it happens any module based radio will be able to have 4096 resolution which is 2 times the resolution of the brand new 14MZ that is $2000+.[/QUIOTE]

Yes but they are not true 4096 systems. At then end of they day they just sample the PPM signal generated but the transmitter which is 1024 steps.

-Angelos

Spartan RC R&D - Visit us at our local club www.helicollective.org.uk

03-06-2005 Over year old.

rjmdubois
Senior Heliman
Location: São Paulo - Brazil

Quote
Yes but they are not true 4096 systems. At then end of they day they just sample the PPM signal generated but the transmitter which is 1024 steps.

I'm think since PPM is analog, it has infinite steps. When the signal is digitalized, the steps are created. So, I belive this sistem could be true 4096 steps.

I'm just concerned about the range. Since it uses 2.4Ghz, I belive the max range is around 1 km. It's good for helis, but not enought for big planes.

Just my 2c

03-06-2005 Over year old.

Angelos
Key Veteran
Location: nr Oxford, OX11, UK

No PPM is not analogue. PPM is a series or pulses. The spacing (time) between pulses define the position of each servo. At the end of the day… whether is it an analogue signal or not, it is computer generated and thus it has a finite number of steps. With the exception of 14MZ no other radio calculates more than 1024 steps servo resolution. Sampling the PPM signal is actually even worst as the pulse jitter will probably be at least 1 bit for a 1024 step system system and probably more in a 4096.

-Angelos

Spartan RC R&D - Visit us at our local club www.helicollective.org.uk

03-06-2005 Over year old.

rjmdubois
Senior Heliman
Location: São Paulo - Brazil

I undertand that PPM signal is coded as square wave, where the lenght (in time) of the peak detemines the servo position for each channel. 1500usec is for center, longer signals, the servo position is to one side, smaller to the other.

I think the process of reading the stick position and transforming in a square wave could be analog. If so, the module receives a 100% analog signal.

Since I never put a TX in an osciloscope, I can't tell for sure.

Any way, I don't think even a world class pilot can fell the difference from 1024 to 2048 sampling, using ATV on the range of 100%.

03-07-2005 Over year old.

Angelos
Key Veteran
Location: nr Oxford, OX11, UK

A CD player uses 16bit for audio coding. The output of the CD player is assumed to be analogue. If we sample this analogue signal with a 20bit DAC is it going to be a true 20bit signal? Is it going to sound better than the original 16bit? I can tell you that it will be significantly worst with digitisation an RFI noise added on it.

The exact same thin happens to your PPM signal. If you put it on the scope you will see that it is already a slightly jittery. Even without any jitter 1bit error will always be present as the pulse generator (TX) and the sampling device don’t have a common synchronous clock.

-Angelos

Spartan RC R&D - Visit us at our local club www.helicollective.org.uk

03-07-2005 Over year old.

Havoc
Key Veteran
Location: Ky.

PPM is analog in that the length of the pulse can vary infinitally between its extremes. Not at fixed steps. So your servo can be placed at any point between 0 and 60 degrees or whatever. PCM works like a CD, PPM works like a vinyl record. Some music nuts claim they can hear the missing "stuff" in the CD and prefer to listen to vinyl records as the only true representation of the music.

http://electronics.howstuffworks.com/question487.htm

03-07-2005 Over year old.

Angelos
Key Veteran
Location: nr Oxford, OX11, UK

Havoc,
PPM would have infinite steps if it was generated by an antique non-computer transmitter. When computers are involved nothing is analogue, everything has a finite number of steps. The minority of transmitters calculate the servo position as a 10bit number. Whether this is transmitted via PCM to the receiver and generate the servo pulses there or whether the pulses are generated locally (PPM) it makes no difference. It is a 10bit number and will have 1024 steps.

Spartan RC R&D - Visit us at our local club www.helicollective.org.uk

03-07-2005 Over year old.

Havoc
Key Veteran
Location: Ky.

I am just talking about the differences in how the data is moved. If the digital to analog conversion produces the effect of having steps that still does not mean that PPM signals are not analog. You can play a vinyl record that sings about zeros and ones but it is still an analog record.

03-07-2005 Over year old.

rdalcanto
Key Veteran
Location: Salt Lake City, UT

I recently emailed the company and asked when they would be available for air/helicopter use. I was told there were no plans for it in the near future. When I read a little on how to use it for ground operation, it sounds like antenna orientation is a big deal - which means it wouldn't work for 3D flying.

Rick

03-07-2005 Over year old.

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Radio - JR & Spektrum DSM > Spektrum receiver/transmitter modules for flying

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