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Spektrum radio

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Old 11-28-2005, 12:25 PM
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Default Spektrum radio

Has anyone done a definitive range test for this radio ? Has this been used by anyopne for other aircraft besides parkflyers? tks

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Old 11-30-2005, 05:04 AM
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Default RE: Spektrum radio

Because of the frequency the "spectrum" system operates on, antenna orientation problems, and the FCC imposed power limitations on those frequencies, their range is extremely limited....very much like the household cordless telephones...some of which operate on the same frequency. It sure wouldn't take long for a conventional r/c plane to get out of range on this system. I think the manufacturers assumption is that park flyers do not get very far away from their pilots, and if they did, their low power and light weight dont carry as much damage potential.
jim
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Old 11-30-2005, 01:50 PM
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Default RE: Spektrum radio

Maybe they will come out with big plane spektrum before long,, does this sound right.,,,
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Old 11-30-2005, 04:02 PM
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Default RE: Spektrum radio

From all that I have read...spectrum technology for the big birds is still just a hope and a prayer, but not likely to become a reality. That is really too bad...our vulnerability, due to frequency control issues, costs us a lot in both money and hard work every time one goes in.
I overheard one tech'y suggesting that we develop a high powered final amplifier for the little park flyer tx, and go ahead and fly outside of the FCC regulations. I doubt that we will see any of that, but it is just another expression of the growing frustration over frequency problems...exacerbated by the huge expansion of park flyer activity.
Keep on hoping.
Jim
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Old 11-30-2005, 06:20 PM
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Default RE: Spektrum radio

At the 2.4 ghz band, the FCC allows a max of 1 watt radiated power. I believe the current Spektrum radio radiated power is well blow this limit so there is definitely potential . I agree will definitely need antenna diversity due to directionality of the TX radiated pattern.
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Old 11-30-2005, 09:07 PM
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Default RE: Spektrum radio

I believe that antenna orientation becomes an issue at 2.4 GHz because of the greater path loss at 2.4 GHz, not because the 2.4 GHz antennas are more directional than 72 MHz antennas. Both antennas are designed to be omni-directional to the extent possible.

We don't see antenna orientation problems much at 72 MHz because the signal strengths at the receiver are very high, so only a very severe pattern or cross-polarization null will affect the receiver. The signal strengths at 2.4 GHz are comparatively weak, so a modest null or polarization misalignment will kill the link.

This suggests the possiblity of improving 2.4 GHz SS performance by use of an antenna diversity system... two or more antennas oriented perpendicular to one another in the airplane so that when the signal falls into the null of one antenna it will be received well by one of the other antennas. Since at 2.4 GHz a dipole antenna is only about 3 inches long, having multiple antennas in a 40 size airplane (for example) would be perfectly reasonable. The 2.4 GHz receivers would need to be specifically designed to make use of the multiple antennas with a voting circuit and separate connections for each (connecting the antennas in parallel would not work).
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Old 12-01-2005, 05:45 AM
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Default RE: Spektrum radio

Good info' JP... There is hope after all!
jim
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Old 12-22-2005, 03:55 PM
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Default RE: Spektrum radio

ORIGINAL: Capt Jim

Because of the frequency the "spectrum" system operates on, antenna orientation problems, and the FCC imposed power limitations on those frequencies, their range is extremely limited....very much like the household cordless telephones...some of which operate on the same frequency. It sure wouldn't take long for a conventional r/c plane to get out of range on this system. I think the manufacturers assumption is that park flyers do not get very far away from their pilots, and if they did, their low power and light weight dont carry as much damage potential.
jim
I would be interested in what you define as extremely.

Current rated range is 1KM, 3000 feet, over 1/2 mile. That should be plenty for anything under 60" wing span.

3000 feet would be 10 football fields. That is a LONG WAY OFF!

Other than Thremal Duration Sailplanes, fast jets and maybe 1/4 scale planes, I doubt many people fly their planes more than 1/2, mile out regardless of size.

My first sailplane was a 2M spirit RTF TD sailplane that you would expect to be flown out a long way. That came with an AM radio rated at 3000 feet. I could get that baby small as a little bird and never had a range problem.

I say 60" as an arbitrary size that I think is not likely to be flown out more than 1/2 mile, about 2500 feet. I don't see 3000 feet as much of a range restriction for the vast majority of flyers. They are marketing it to electric pilots because those planes tend to be smaller, but 1.5M gliders, slope gliders and even glow planes could probably use it within the size I mentioned. But this is just my opinion.

The airplane version uses a dual antenna system with internally redundant receivers each working on a differnet channel so that orientation should not be a problem.

I have read of ground tests of over 3K feet with success, but nothing formal. I would say if you stay within 2500 feet, 1/2 mile, you should be fine!
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Old 12-22-2005, 04:59 PM
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Default RE: Spektrum radio

Ed..it looks like you have more encouraging information than I do. I agree that there are few pilots...if any...who would intentionally try to fly that far out. But if the systems really will work reliably at those ranges that you mention...why then do the manufacturers bring it to market for only little electric park flyers?
Jim
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Old 12-22-2005, 05:13 PM
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Default RE: Spektrum radio

For one thing it offers the park flyers an option of a system that doesn't cause problems with 72mhz systems plus they do not have to worry about the formality of frequency control with fellow park flyers.
Like any other product, it won't sell to all but their market should be large enough to make it worthwhile.
ORIGINAL: Capt Jim

Ed..it looks like you have more encouraging information than I do. I agree that there are few pilots...if any...who would intentionally try to fly that far out. But if the systems really will work reliably at those ranges that you mention...why then do the manufacturers bring it to market for only little electric park flyers?
Jim
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Old 12-22-2005, 05:17 PM
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Default RE: Spektrum radio

I picked up this radio last weekend and had a chance to test it yesterday. I put the Spektrum Rx into my 40" foamy Extra that was using a Hitec Electron 6 Rx (JR 8103 Tx)

It seems to perform with no problems as far as I could see the plane (I was loosing sight now and again, so it was at least as far as I had flown the plane with the Electron 6 Rx)

Now that I have flown it on my foamy test plane, I put the Rx into a Fliton Mini Extra 330. Plan to test it this weekend.

Only two things so far that bug me about the Tx. It does not have a timer function and the Tx antenna is not removable[:'(]

No rudder expo didn't affect me since I had been decreasing that on my JR8103 anyways to get faster response.

I'll have to give it some time before I decide if this is a keeper or not.
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Old 12-22-2005, 05:44 PM
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Default RE: Spektrum radio

I understand that the DX6 is based on a JR radio.

DX6
http://www.spektrumrc.com/Products/D...ProdID=SPM2460

I think it is the XF631 with some enhancements.
http://www.jrradios.com/Products/Def...*&tag=hqlr4007

DX6 DSM 6CH Park Flyer System w/4-S75 Product Specifications
# of Channels: 6 Channels
Band: 2.4GHz
Servos: 4 - S75 Sub Micro
Receiver: AR6000
Model Memory: 10 Model Memory


Tech Notes


System Features
• Digital DSM™ Spread Spectrum Modulation
• 10-model memory
• Dual rates on aileron and elevator
• Exponential rates on aileron and elevator
• Dual and exponential rates can be combined on one switch
• Trainer system compatible with Spektrum™ and JR® radio systems.
• Adjustable stick length
• Throttle trim only affects idle position
• Two-speed scrolling
• Throttle-smart fail-safe system
• Digital trims for precise adjustment

Airplane Specific Features
• Aileron to rudder mixing
• Elevator-to-flap mixing
• Flap-to-elevator mixing
• Flaperon mixing
• Delta wing mixing
• Aileron differential
• V-tail mixing
• Three programmable mixes

Helicopter Specific Features
• Two 3-point throttle curves
• Three 3-point pitch curves
• Flight mode switch can combine throttle curves, pitch curves, dual and expo rates,
and gyro sensitivity
• Throttle hold
• Revolution mixing up and down
• One programmable mix
• Supports 120° CCPM mixing
• Independent digital trim setting for each flight mode

AR6000 Receiver
• DuaLink™ (pat pending) incorporates two receivers in one
• Ultralight 7 grams
• Compact design 39 x 39 x 9mm
• Smart fail-safe prevents motor start up if Tx is off and gives low throttle if signal is lost
• Short 3.75” antennas for mounting convenience
• Easy bind plug


A few items from their FAQ - I hope they don't mind my copying them here:

Technical

Won't other 2.4Ghz devices like phones and wireless computers cause interference?
No, the FCC requires that all 2.4Ghz DSS devises be "smart"- incorporating collision avoidance such that when any DSS system is turned on, it scans the 2.4GHz band until a channel that is not being used is found then begins transmitting on that unused channel.


Back to Top

What is the range?
Typical range is about 3000ft. depending on conditions.


Back to Top

What kind of response time does Spread Spectrum have?
Spectrum's DSM system is optimized to give the fastest possible response time of 5.6ms. Typical FM systems offer a response time of 12 to 18ms.


Back to Top

Will the DSM system affect or be affected by other transmitters on 27 or 75mhz or lap counting systems?
No. The DSM system operates in the 2.4Ghz ISM band and is well above the range of any equipment including lap-counting systems presently in use.


DX6

What about telemetry?
As you may have seen, we have telemetry for surface systems that give real-time feedback for temperature, voltage, speed/RPM and more. We felt that the park flyer market would put a premium on small size and low weight, so we designed the AR6000 receiver without telemetry.


Back to Top

What makes the DSM 2.4GHz RF link so strong?
Our patent-pending DuaLink technology offers a truly redundant system in frequency, path (relationship between the antennas) and time. It makes the link virtually impenetrable by any sort of interference.

Why park flyers only?
This unit was specifically developed for sport park flyers. It has plenty of range for park flyers. Just as we have a different product for airplanes than cars, we'll have a different product for sport flying aircraft that fly at a much farther average range than a park flyer. We wanted to keep this unit small, light and affordable - all attributes we felt park flyers need. Sport flyers have different needs - and we will have products for them, all in good time.


Back to Top

What does DSM mean? DSM is a proprietary RF protocol that is based on 2.4GHZ ISM band. It stands for "Digital Spectrum Modulation." Think AM, FM, PCM and now… DSM.

FAQ - DX6 discussion starts about 2/3 of the way down
http://www.spektrumrc.com/DSM/FAQ.aspx
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Old 12-22-2005, 06:09 PM
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Default RE: Spektrum radio

Hey Airbike....thanks very much for developing, and sharing with us, your own impirical data. Based upon your tests and the information from aeajr, I am quite tempted to buy one and put it into one of my 46 size glow fuel planes and give it a try.
Before getting myself into trouble along the way...I wonder if the AMA has developed any position prohibiting its use in aircraft other than the electric park flyers. The real question being...would such an application void the insurance?
Thanks all for the info...I'm getting very excited about this now....frequency "protection" is something I have wished to find for a long long time.
Jim
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Old 12-22-2005, 06:23 PM
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Default RE: Spektrum radio

Hey Capt,

I was/am tempted to install the Spektrum Rx into my electric pylon plane (30" wing span, 16oz all up weight, these specs seem to say this is a parkflyer, except that is was radared at over 120mph doing level laps, prob 140+ in a dive)

But I think I will wait a while for more information from all of the users to see if there are any hidden gremlins. Meanwhile, I'll continue to check out its performance in the Fliton Mini Extra.

I would suppose that Horizon specified this system for parkflyers and micro-helis to limit their liability exposure while the technology matured a little. At the same time, they've been able to be the "First to Market" to grab a significant market share even if others come out with similar systems, perhaps based on something just different enough not to infringe on any patents.

Oh and about that pylon racer; I'm waiting for a replacement now since it took a glitch (electron 6 Rx) when it was low and banked hard and at about 100-120mph. Nice puff of dirt it threw up!!![:@]
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Old 12-22-2005, 06:38 PM
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Default RE: Spektrum radio


ORIGINAL: Capt Jim

Hey Airbike....thanks very much for developing, and sharing with us, your own impirical data. Based upon your tests and the information from aeajr, I am quite tempted to buy one and put it into one of my 46 size glow fuel planes and give it a try.
Before getting myself into trouble along the way...I wonder if the AMA has developed any position prohibiting its use in aircraft other than the electric park flyers. The real question being...would such an application void the insurance?
Thanks all for the info...I'm getting very excited about this now....frequency "protection" is something I have wished to find for a long long time.
Jim
In the November or December issue the AMA said they hoped clubs would welcome this new technology. I am not aware that they have ever placed a restriction on using a legal radio/frequency at an AMA field based on the power plant in the plane.
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Old 12-22-2005, 06:51 PM
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Default RE: Spektrum radio

HI Ed...Nor am I aware of any AMA restriction, but just thinking ahead...since the system is marketed for park flyers, couldn't it then present the AMA with an "out" in the event of an incident involving its use in something other than a park flyer? Im sure not looking for trouble, but rather, I am trying to not run into it blindly.
Thanks for all your previous info'...based on that, I am so very tempted to give it a try in a small glow plane.
I'll be watching this thread closely to see if anyone else has done it...and what their results were.
Thanks for all,
Jim
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Old 12-22-2005, 07:19 PM
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Default RE: Spektrum radio

Why not contact the AMA via e-mail and ask them? That would be easy.
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Old 12-22-2005, 10:48 PM
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Default RE: Spektrum radio


ORIGINAL: aeajr

Why not contact the AMA via e-mail and ask them? That would be easy.
Yes, that would be easy, but I bet you won't get an answer and if you do it will be very general and non commitable. Why? What is the definition of a Park Flyer? Is it only electric? What is the max distance you can fly a park flyer? See the problem!

My $.02
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Old 12-22-2005, 10:52 PM
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Default RE: Spektrum radio

Again, AMA has already published endorsement of this system at AMA fields. The question was could it be used with somethign other than parkflyers.

Since there is no definition of a parkflyer, unless Spektrum has published one, I don't see how you can violate the use of the radio.
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Old 12-23-2005, 06:47 AM
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Default RE: Spektrum radio


ORIGINAL: aeajr

Again, AMA has already published endorsement of this system at AMA fields. The question was could it be used with somethign other than parkflyers.

Since there is no definition of a parkflyer, unless Spektrum has published one, I don't see how you can violate the use of the radio.
I agree with this statement. The last paragraph is why you will not get a definite yes or no from the AMA.

We already have several 72 MHz park flyer receivers (GMS, Hitec Feather, etc) and this question has not come up that I know of.
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Old 12-23-2005, 07:33 PM
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Default RE: Spektrum radio

I am unable to email the AMA through their web site...when I click on anyones name to email...all I get is some cryptic error code.
How about someone else...who can get through to them, posting the question about using the Spektrum system in something like a 40 size glow plane.....etc...will it negate the insurance...my club secretary thinks that until the AMA tells him the radios are OK to use...they cannot be used at our field...even in a "park flyer".
I guess we need the AMA to step up here and clarify their position.
thanks for the help.
Jim
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Old 12-23-2005, 08:52 PM
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ORIGINAL: Capt Jim

my club secretary thinks that until the AMA tells him the radios are OK to use...they cannot be used at our field...even in a "park flyer".
I just bought the Spektrum today and will be flying it on January 1 at our numb thumbs fly.

I think your secretary is way off base. AMA says if any radio is FCC legal then you are free to use it and their insurance is covering you. They do not have to approve it!
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Old 12-24-2005, 08:10 AM
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Default RE: Spektrum radio

Your secretary is in charge of your club? Amazing

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Old 12-24-2005, 10:16 AM
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Default RE: Spektrum radio

As a board member of a local club, I see this as a topic at our next board meeting. My guess, is that we will start seeing these things as the weather warms up here and will need a plan to convey the clubs stance on these radios.

Personally, at this point, I wouldn't want anyone using one at our field in anything other than an electric parkflyer until there is evidence of its safety and AMA approved.

I would hate to have an "incident" with one of these radios and have the field jeaporadized because it was being used.
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Old 12-24-2005, 11:05 AM
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Default RE: Spektrum radio


ORIGINAL: daven

Personally, at this point, I wouldn't want anyone using one at our field in anything other than an electric parkflyer until there is evidence of its safety and AMA approved.
Come on fellows, you are over reacting to a non issue! Do you or your club make sure no one uses a GWS or Hitec Feather in other than a so called "Park Flyer"? Do you make every one range check before every flight? What is your club criteria for a range check?

BTW, is it illegal at your club to use a wideband receiver?

Geeessss!
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