[martinic]

From what I've read, it's less to do with the DX6 than it is to do with the antenna diversity offered by the dual RX receiver models, particularly where signal blockage can be an issue (metal motors, large batteries, CF frames, etc.). The DX6 is a DSM TX and will only work with DSM RX models, the DX7 will work with either DSM or newer DSM2 RXes. All of the dual RX receivers are DSM2 only and will not work with the DX6.

With the price of a DX7 being so low, why bother risking an expensive model and/or safety with potential signal blockage?

The DX7 also provides servo sync; which for 120 CCPM helis results in signals for all cyclic servos being executed simultaneously (not applicable to non-CCPM helis like the Raptor 30 though). Another safety benefit is model match which eliminates the potential of flying with the wrong model selected (the bind code is unique for each model, not just the TX).

[Flypaper]

The DX6 AR 6000 rcvr has dual rcvrs. I have 6 of them that I use with both the DX6 and 7

[martinic]

Not dual channel, but actual dual receivers separated by a wire harness. You install them on different planes (surfaces) at angles to each other, seperated by the cable. It provides for better diversity than a single unit.

See this post on RR by Paul Beard (Spektrum designer) - midway down the page.

It's not really a range issue, but performance in reflective environments.

Fuel tanks, engines, mufflers cause local fading - where the direct signal is cancelled by the reflected signal - which can arrive 180degrees out of phase.

If one of the radios is faded, the other radio even a small distance apart, cannot be in the same faded situation. 2.4GHz is a short wavelength, so it is quite vulnerable to fading versus 72MHz.

This is the path diversity part of the system. Spektrum also uses frequency diversity (the reason for 2 frequencies) and time diversity (the data is send twice per packet on both frequencies). The combination of path, frequency and time diversity systems yield an extremely robust link.

It's very rare for both radios to be faded simultaneously, this would take a very complex series of reflections.

You can observe this using the FlightLog on an AR9000. The remote radios can individually have literally hundreds of fades per flight, but only a couple of simultaneous fades per flight.

Now, the two-cushion-bankshot, is that the main radio and remote radio dipoles can be orientated at 90degrees to each other. The system then does not suffer from polarization loss. This is only a benefit at extreme range.

The three-cushion-bankshot is that if one radio develops a fault in flight, you can still fly back safely. The receiver won't drive the servos next time you turn on.

[Flypaper]

From the DX6 manual. Quote: Reciever. Each AR6000 features a Dual Link technology and is actually 2 recievers in one, hence the dual antennas. When turned on, the first rcvr scans the 2.4ghz band untill it finds the specific trans. code( Called Guid) that has been programmed to recognize and locks on the signal. The whole process takes less than 5 seconds. The reciever is then locked onto that transmitter via two independent channels and is vertually immune to model generated or outside interference. Unquote;
The two recievers just happen to be in one case. The AR 7000 is in a 1/4 scale and the two AR 6100s, which only have one rcvr, are in the foamys.
Gotta have lotsa recievers

[martinic]

I understand that the AR6000 has two RXes contained within the one unit - my point was that the remote RX (two separate linked units) provides spatial diversity.

[ve1ahm]

I have always wondered what a park flyer range was. NO one would committ to a definate answer as to the distance. A friend and I were using DX6 to fly small electric planes. Mine is a Sig Lil Rascal. The DX6 and the 6000 receiver are dsm version1 . I got my friend to stand at the end of my driveway while I got into my Caravan with the plane all set to go. He operated the controls continuesly as I drove down the road. At almost .5 of a kilometer the controls started to show signs of malfunctioning. This is with the plane INSIDE the vehical. By the time I got the car stopped it was .55 of a kilometer. I got out of the car with the plane and the controls were now working 100%. I also deciced to hand tumble the plane while watching the controls. NO sign of loss of control. I and my friend now have a do not exceed distance to work with. Besides at .5 of a kilometer the 39 inch wing span Lil Rascal is almost non visable to see anyway.

[techrtr]

I fly a 50 size nitro with a DX-6 and have never had a problem with it. Mind you, I fly pretty close to myself. The thing I find funny is, there are parkflyers that go 80 miles an hour and the DX-6 is supposed to be just fine for them. Why wouldn't it be okay for a heli that never gets more than a couple hundred feet away from the pilot?