matt1977

Hello,

Could someone point me to some documentation that shows the approximate range of Spektrum's DSM vs. Spektrum's DSM2 vs. Futaba FASST.


I know that DSM is substantially less range than DSM2 and FASST, but I have looked every where and can not find any specs on these.

I have a buddy that has a plane that he flies way out of site with the use of this camera mounted in the plane. Pretty darn cool actually.

He was wondering if he bought a 2.4Ghz system if he could go just as far as he can with the 72Mhz.


Any one have any links to such specs?

Thanks for your help.

JCINTEXAS

Quote: "I have a buddy that has a plane that he flies way out of site with the use of this camera mounted in the plane. Pretty darn cool actually."
__________________________________________
Your buddy should check AMA rules on flying a model beyond visual range. I'm thinking this is a "No No".
Regards
JC

matt1977

Point noted.

But can you answer whether 2.4Ghz has as much range as the 72Mhz?

carrellh

For product liability reasons no manufacturer or distributor will publish anything more than what you've already found. All any of them will say is that it will control a model as far away as an average person can see it with the naked eye.

Flying beyond visible range is potentially a bigger issue than AMA safety code. People who are not AMA members do not care about the safety code since they never agreed to follow it.

FAA and other government agencies (who we all should care about) can get really cranky about that sort of thing.

Foamaholic

My Feedback: (1)

All things being equal, range is not a problem with 2.4.

vasek

My Feedback: (4)

Actually that is not true. The Dx6 (DSM) is NOT full range. Lots of info on that, do a search.

V.

matt1977

Thanks guys,

I will have to tell that knot head to be careful, he may not even know it's illegal. Because I didn't.

But that did spark the question of whether 2.4Ghz has a longer range than 72.5Mhz.

I did know that the DX6 was for park flyers, thats the DSM. I was mainly wondering about the DSM2 and FASST.

So there is no nerdy explanation anywhere as to why one would have farther rang over other?

They are pretty much equal?

sky1000

The factors involved in radio control distance are:

1. frequency
2. transmitter power out
3. receiver (capture) sensitivity
4. transmitter antenna gain
5. receiver antenna gain

Higher frequencies are always attenuated more (in air) than lower ones.

Hence, all things being equal, 72MHz will have a greater range than 2.4GHz.

Remember that at 2.4GHz a ¼ wave length is only about 1.2�. This, unfortunately, is about the length of pine needles and some other conifer leaves. When wet, they do a fine job of heavily attenuating the 2.4GHz signal.

72MHz is generally immune from this absorption.

Foamaholic

My Feedback: (1)

People have specked out their planes with dsm although not recommeded by Spektrum.

Rafael23cc

My Feedback: (6)

Does he speck it out or does he actually fly behind objects and thus not in line of sight?

2.4 does not like to penetrate objects. So any flying outside line of sight is a gamble I would not take. Specking the aircraft out, as noted before is not recommended but has been done. Again, specking an aircraft is in derect conflict with AMA and FAA rules.

Rafael

BarracudaHockey

My Feedback: (11)

As soon as you fly beyond visual range (intentionally ) you become subject to the FAA and are no longer a hobbyist. Trust me thats not an issue you want to stir up.

DSM has the same range as DSM2, the difference is DSM2 helps prevent shadowing of the primary receiver by say an engine or battery/esc, by use of a secondary reciever oriented differently. With no obstructions any of the systems we use, 50, 72, DSM, FAAST, DSM2 will operate farther than we could possibly see the model to control it.

Foamaholic

My Feedback: (1)

Good points. We don't have to worry about range, although there are some receivers on 72 that don't have much range at all.

Julez

And one importent factor:

6. Coding gain.
This is one great advantage over MHz systems.

Recently, Fasst was tested to 3.8km from a swiss mountain top into a valley. Good enough for me

tkilwein

1.5miles no problem using 14MZ and 6014. 1.6 miles started to get jitter movement on servos.
Set TX down at 4ft elevation, vertical antenna in servo test mode and take RX + servos at 4 ft elevation and drive away until servos start to become jittery, no longer smooth movement.
Way more than I need.