What's on your workbench?

[Jim_Marconnet]

Originally Posted by ghee-grose

Does it come with a receiver that can change frequency or do you have to buy crystals to match?

The simple answer is that it's all automatic, nothing else to buy or to do.

The longer answer from their web site, pieced together and edited down a little:

Just turn your transmitter on - in an instant the output light comes on. Then you turn on your model. In an instant you have a direct, solid, secure link. There's nothing to fiddle with.

When you turn on your DX6 transmitter, it scans the 2.4GHz band and picks two frequencies which show the least activity. That's right, there two frequencies used with the DX6 system.

With DuaLink, the transmitter randomly selects two frequencies from the band, and transmits the same information on both simultaneously. The AR6000 receiver actually contains two complete receivers with individual antennas. Since the receiver is mobile, the path (a technical term for the relationship between the position of the transmitter antenna relative to the receiving antenna) is constantly changing. Even if one path (or frequency, for that matter) is lost for one frame instant, the other will be perfectly connected to the transmitter. So it is truly a redundant system - in multiple ways - frequency, path and time.

Because there are two antennas with different positions, if in the unlikely event a frame is dropped (loss of sgnal for more than 15ms), the other receiver is already on-line. Result: No interruption in signal. No dropouts. No problems. Just a strong, solid link. That's what DSM DuaLink is all about.

Shorter-yet-answer (found in their FAQ!) ----- It's magic!

jim

[Tram]

What does a new RX cost each time you want to buy one?

*EDIT* $60 bucks.. Weighs in at 7grams.. Not bad..

[ghee-grose]

Well with that information I can see why you're waiting on that radio. Sounds like a glitch-free environment with that one.

[Mars Flyer]

I'll chime in on the DX6 because I've been reading about them as well. For $200 for xmtr, rcvr, and 4 servos this is a good deal even without the cool spread spectrum stuff. The rcvr cost is the same as a decent dual conversion 72 MHz unit. That is a full-featured xmtr with 10 model memories and all the mixing and programmability you would expect. It should start a revolution in radios. I'm betting the other manufacturers will follow soon - or be lost in the dust.

Rob

[dee-grose]

...maybe this should really be in the chit-chat thread, but I'll join in

There just so happens to be a review of the DX6 system on rcgroups. See here:

http://www.rcgroups.com/links/index.php?id=4936

[Ultralight]

Wow! It sounds like the perfect set up for a parkflyer. Let us know how it works out Jim.



Jason

[nuevo]

The radio is Spread Spectrum. It doesn't use "one" frequency, but hops among a pre-defined set of frequencies according to a pseudo-random code. The "code" is the channel, and multiple radios can be transmitting at the same time. The TX stays on one exact frequency a small fraction of a second and then hops to the next frequency. The receiver (binding they call it), knows the same code and they move in lock step. Another TX/RX pair will use a different hopping code, and the radios will rarely "step on" each other. There is enough redundancy in the data sent that these minor "collisions" are not a problem.

Their frequency is 2.4Ghz as opposed to our 72Mhz, so they won't interfere with "normal" radios.

Only time I could see a problem is if 20 or more of the TX's were all on at the same time, or there was outright interference in the 2.4Ghz band. What else is on the 2.4Ghz band? Wireless networking, microwave ovens, and some cordless phones.

Jim, Yes these radios are the future, but don't believe that your receiver is totally immuned to interference or noice from the ESC. Noise is noise, and it degrades the signal. I used to work at a radio company that did this stuff. In the case of your radio, the noise is way outside the 2.4Ghz frequency of the receiver, but the noise is physically right next to the receiver too. This "close" noise can swamp the automatic gain control (AGC) circuitry in the receiver. An crude analogy would be you trying to listen to a conversation 1000 feet away, while standing next to a jet airplane with the motor running.

I'm sure enough testing has gone into these radios. Horizon/JR are one of the best brands around, as far as I'm concerned. I am excited that RC is finally getting into spread spectrum. These radios are the first wave, I'm sure.

[Jim_Marconnet]

Originally Posted by JonStone

The radio is Spread Spectrum. It doesn't use "one" frequency, but hops among a pre-defined set of frequencies according to a pseudo-random code......

Actually from one of their reviews at: http://www.horizonhobby.com/Explore/...ID=1535&Page=1

DSM USES DIRECT SEQUENCE SPREAD SPECTRUM

You've probably heard of the familiar form of Spread Spectrum called "Frequency Hopping." This form uses a system that has the signal transmitting on one of the 80 available frequencies for just a few milliseconds, then hopping to another channel, and so forth. This is all done randomly and so fast that it won't' affect other "hopping" systems, nor direct sequence.

Our system, over five years in development, started out using a frequency hopping system. But the limitations of this format in regards to robustness of the link and slow speed sent our designers into the Direct Sequence side. Whereas frequency hopping is "old technology," the newer Direct Sequencing offers a much more robust RF link, faster speeds - yet it is exponentially more difficult to program. And it's the programming where all the magic is. Understanding what to do with hardware is the "secret" to DSM Spread Spectrum technology.

[nuevo]

Thanks for the correction Jim. I'm excited to see the system in action.

[Mars Flyer]

The DX6 is certainly interesting technology. Seems that "spread spectrum" is more hype than truth. Being an anal retentive spaceship designer I see one possible failure mode already. Suppose these radios get very popular and there is a guy down the street flying with one too. With 80 channels taken 2 at a time there is a 1 in 40 chance that his system will pick one of the frequencies that yours does. Since he is some distance away the trees and houses block the signals when you are on the ground and frequency selection is being made. Once in the air your plane has a line of sight to his transmitter and one of your links gets clobbered. Maybe the other will be OK, maybe not. There seems to be some link margin issue being addressed with the 2 channels already. Maybe multipath? Same problem could occur with interference from a cordless phone or wireless network. Channel selection is done on the ground and airborne exposure to interfering signals may not be detected. Too bad it isn't true frequency hopping. This would reduce the chance for such problems dramatically. Although, lots of transmitters frequency hopping simply increases the noise level which isn't good either.

I couldn't find the DX6 in a quick look through the latest issue of the Horizon catalog. It was in there big time in the previous issue. I'm not sure what that means.

None of this discussion probably belongs in a build thread but it sure is fun.

Rob

[Jim_Marconnet]

Originally Posted by Mars Flyer

I couldn't find the DX6 in a quick look through the latest issue of the Horizon catalog. It was in there big time in the previous issue. I'm not sure what that means.Rob

I've not seen their printed catalog. On their web site, searching for DX6 it shows up http://www.horizonhobby.com/Search/D...&OverallCatID=

It shows as "Due mid-December". Earlier this month it was "Due late-November". Apparently it's coming..... but so is Christmas!

Edit--> Sorry Gang! -- Getting frustrated - time to chill! Jim

[Miderror]

Originally Posted by JonStone

I'm building 2 Supras (134" span glider) this winter. Looks like this photo.



I started a build thread. Follow along if you like. I tell you, those Supras are keeping me off the street. It will take me a few more months just to finish the Supras.

Supra build thread



Also have an Olympic 2 kit, and bought the Overlord foamie kit from Todd.

Somehow I'm supposed to finish all of these kits this winter.

I'm following your thread Jon. Very nice.

[Fyrwalker]

Evening ya'll,
hope everone had a great holiday. here's what i'm working on.
sweet stick 40 a friend gave me last year, he started it in 1984.
i modified the wing with two servo mounts instead of the one servo and bell cranks,made it into a taildragger. hope to have it done soon, i'll post some pic. later.

[Moonbeam Six]

Since I am still diddling with my Mini Diddle MAX, I guess it would be correct to include it as being on my workbench. I also have the parts (or at least most of them) cut out for a Diddle Champ. BTW, watch the printer settings when printing out plans in .pdf format or you will get the wrong scale. I also have a Great Planes Escapade foamy thing that has been dormant for the last couple of months. It is at least 90% complete. Plane still in the box, on paper, or in my head don't count as being "on the workbench," so I won't mention them.

Frank

[nuevo]

What's a Mini Diddle Max and a Diddle Champ? I looked around & couldn't come up with anything.