metabolicmaggot

does anyone actually know the range of the dx6?

alan0899

G'day Mate,
Range isn't the issue, with the DX6, they are fine with electric park flyers, that are kept close.
The real problem comes in if you try to use them for glow aircraft, they don't have the diversity aerials, like the DX7 RX does.
So, things like fuel tanks & the engine can get in the way of the radio signal, & into the ground you go.

metabolicmaggot

I see, so I should just go ahead and get the dx7, that is an expert radio that will take me as far as I can go right? will never have to worry about needing an upgrade?

alan0899

G'day Mate,
I have a DX7, in my 160 size Katana, see pic, works perfectly, has 6 servos, 2 for aileron, 2 for elevators, 1 rudder & 1 a mini for throttle, I only use 2 of the 6 available mixes, 1 for engine kill, & 1 to mix the elevator servos, it is the bees knees, as far as I'm concerned, & has plenty more to offer, if & when I need it.

aeajr

My Feedback: (2)

Range on the DX6 is much debated since Spektrum has never released figures. In other than carbon fuselages, you are pretty save at about 1500 feet with many finding 2000 feet is reliable. There have been many reports beyond these ranges, but these should be safe.

The receiver will work in anything but there is concern that a glow motor, fuel tank or other large metal objects could obscure the view of the receiver.

With the DX7, you can use the two piece receivers, like the AR 7000, that actually have two receivers separated by some distance, so they can see around large metal objects. Also the DX7 has a higher power output, so it provides longer range even with the AR6000 receiver that comes with the DX6.

Hope that helps.

If you have the money, the DX7 is a far more flexible, longer range system. If you are sure you will only need short range, the DX6 is fine.

kryptonite

Actually that's not quite true. The DSM2 protocol actually uses a smaller RF output level. This was noticed by a number of users when comparing DSM and DSM2 on spektrum analyzers - the difference was quite apparent. This was actually confirmed by Paul Beard of Spektrum when questioned at the Toledo show. The AR7000 gets it extended range from a far superior (ie more sensitive and discriminating) front end. It also explains why you get extended run times on the transmitter when running on the DSM2 protocol.

aeajr

My Feedback: (2)

OK, I am open to be corrected here but help me understand it. I certainly understand that the AR7000 can be more sensative than the AR6000, giving the AR7000 more range. No different from 72 MHz receivers. It is the receiver that determines the range for any given transmitter.

However we are not talking about one transmitter but two. I was told the output on a DX6 was around 60mw and the DX7 around 100 mw. That would mean that the AR6000 has a stronger signal to listen to when a DX7 transmits than when a DX6 transmits. That should lead to greater range. Crank up the signal and you should be able to hear it further away.

Are you saying this is not true?

Or, are you saying that the DX7 does have a greater output but is has no impact on range.


Remember I am tlaking about OUTPUT wattage, not input wattage. So a more efficent transmitter can put out a stronger signal on less input power. The receiver doesn't care about the input power, only the output power.

Just trying to understand because that is not how I understood it. It has been many years since College and physics and all that stuff I studied. But I do understand the basics.

Very few of us are RF engineers. Since Spektrum has failed to provide good guidance on range, we mere mortals have to struggle to comprehend how this stuff works and the practical range that can be expected.

Thanks for trying to dumb it down so even I can understand it.

tomlee

My Feedback: (1)

Hi guys- I have been flying AR6000's since I first sprektrumized a JR6102. I have moved up to a DX-7 and I am still using the AR6000 and now some AR7000 receivers. If you check the spektrumizing the 6102 threads, you will find the AR6000 to have been tested over 1 mile in the Dallas area.

I have them in my "60" size airplanes with 91-4stroke engines. Never a known radio problem in any of my airplanes.

I am using both 4.8v and 6.0v NIMH receiver batteries, slowly converting my entire fleet to 6.0v where they will fit.

Part of my pre-flight is to field charge those NIMH's as I am setting up the rest of my stuff.

kryptonite

One of the members of my club is an RF engineer and loves bleeding edge toys. One of the things he did was to hook up both the DX6 and DX7 to a real-time spectrum analyzer. What he noticed was that the two spikes seen on the analyzer ( corresponding to the two selected transmission frequencies ) was significantly thinner and peaks lower on the DX7 than than the DX6 - but only when the newer receiver ( AR7000, or AR6100 on the DX7 ) is used. Remenber than when used with the older receiver, the DX7 reverts to DSM and outputs with same RF output level as the DX6. This means that the DSM2 protocol was implemented with a different power level than the older DSM protocol. Now the DX7 was quoted as having a higher RF output than the DX6, as you said. This probably came from the FCC certification document. Since the DX7 is a dual protocol transmitter, it has to be certified for use with both types of receivers.
I speculate that the higher RF power is attributed to DSM and not DSM2, and the product is then certified at that higher level. It could be that the DX7 actually is MORE powerful than the DX6, so your little AR6000 based parkflyer can be flown a wee bit farther on the DX7.

Now the interesting part is that Spektrum did not specifically mention any of this in their product literature. Perhaps they don't want their customers to incorrectly infer that lower power levels would mean reduced reliability and range. Our club member spoke with Paul Beard and he did confirm that DSM2 uses less RF power. We all have no doubt that the AR7000 has better range - this has been demonstrated in independent tests. Its interesting that this has been achieved using less power, not more.

aeajr

My Feedback: (2)

The range is more a function of the sensativity of the receiver than the power of the transmitter. We have seen this all across the board in 72 MHz. Same radio talks to a GWS 4 channel and rated range is 500 feet. Might still work at 1000 feet, might not.

Same transmitter with a Hitec Micro 05S is rated at 1 mile. It might work at 2 miles, might not but very few planes can be seen at 2 miles in order to fly them. About the same size and shape as the GWS receiver but more sensative.

Now, a JR transmitter and a Futaba might put out somewhat different power levels but the difference is not enough to matter. If you say the DX7 and the DX6 are putting out similar power levels, then the added range of the recievers is strictly a function of the receivers and the AR6000 would have similar range with a DX6 and a DX7.

Again, Spektrum tells us very little so we have to guess, or depend on engineers, like your friend to run tests, then speculate what they mean.

Did he say what he thought the output level was for hte two transmitters? Could he measure that?

kryptonite

There is no doubt back in the analog FM world of 72 mHz, the receiver is the primary determiner of the range. Most FM radios output 750 mW or less and that is more than enough to get out to 5000 ft with the very best receivers. The same radio may only work up to 1000 ft with a receiver with a poor front end. It all amounts to the design choices and compromises that have to be made to keep component cost down. Now it gets more interesting in the digital world. Thanks to forward error correcting and other noise reduction schemes, we have more variables that determine signal quality. Of course power comes into play. and having more power will produce a stronger signal for better propagation and to better compensate for atmospheric attenuation but it can also have a deleterous effect. Extra power will cause more noise to be seen by other spectrum users and they may compensate by increasing transmission power themselves - all contributing to the overall noise floor.

I find the 802.11b wifi networks to be an extremely enlightening view into the world of digital spread spectrum. You can see the protocol changing bitrates to adjust for noise and base station range factors and see things that can cause transmission rate changes or even connections drops. I experiment quite a bit with different wifi cards and note the difference in performance due to different chipsets or even from firmware revisions. A good, high sensitivity card constantly outperforms a higher power, but lower sensitivity card.

Most of the same issues apply to our DSS systems for model use, which run at a much lower bitrate and therefore can be made more robust. Spektrum has learnt a lot from their DSM protocol in the past two years and made many enhancements to come out with DSM2. I have no doubt that DSM2 is more robust since it can do more with less RF power.

As to what the exact power levels are between the DX6 and DX7 on DSM - sorry I do not have the values, and I doubt it can be measured to the same accuracy as found in the FCC certification laboratory. Another interesting thing is that DSM2 is bidirectional to some extent. The receiver actually transmits to the radio, abeit at very low levels. I wonder ( since this is speculation ) that the radio is changing the RF power accordingly based on the proximity of the receiver. This might invalidate the test since its made with the receiver in close proximity.

bluemax50

I have a DX6 and use it flawlessly with what it is designed for, Parkfliers. I fly my planes as far and as high as I can still see them with no problem. I don't know what the actual range is and I would guess it depends on numerous changing external and internal factors anyway like any radio signal. I quess the point I'm trying to make is when used for what it is designed for, parkfliers you'll be able to fly them as far as you would be comfortable with. If you can't see the plane who cares how well it's recieving a transmitted signal anyway!. I suspect interest lies more in trying to use the DX6 in larger aircraft which because of their size can be seen so flown at larger distances which isn't what the DX6 is designed for. If you flying electric parkfliers like me exclusively then the DX6 is a fantastic buy. I you want if for large aircraft, it'll work but watch the distances and antenna routing or better yet but the DX7

aeajr

My Feedback: (2)

Now, if there was only a standard, universaly accepted definition of a parkflyer.