New surface radio system recommendations?

T-Maxx

I'm looking into buying a new radio system for my surface models. At the moment I'm leaning towards the JR XS3 (40mHz, synthesized). (One receiver will do at the moment.)

However, what is the lowdown on the 2.4gHz systems, are they the way forward or not yet?

Any other systems you might recommend?

workaccount

T-Maxx wrote: »

I'm looking into buying a new radio system for my surface models. At the moment I'm leaning towards the JR XS3 (40mHz, synthesized). (One receiver will do at the moment.)

However, what is the lowdown on the 2.4gHz systems, are they the way forward or not yet?

Any other systems you might recommend?

What are you using at the moment?

Spektrum DX3 http://www.modelflight.com.au/pics/spektrum_dx3_6c.jpg or the latest one - what an awful design. http://www.rctechonline.com/products/radios/spektrum/dx3r/SPM3100.jpg

T-Maxx

27mHz AM (cheap-n-nasty):o

lotus791

go 2.4ghz radio + modules if the pocket will meet the cost.....futaba faast sys early ones had some heat probs with the reciever .supposed to be solved now ....personally i use a futaba 3pk with spek 2.4 hrs system..issue free.

vectra

I have a feeling that Plug has a DX2 or DX3 Transmitter he would sell. You can buy a receiver then for around £30
Sorted

coolwings

Remember - 2.4 ghz is direct line of sight reception only.
For an offroad model, one that will go into depressions, round tree trunks, and maybe under tunnels and behind hillocks that make jumping possible you won't have control while it's "back there out of view".
You will never be able to send a buggy down a pipe due to 2.4ghz radio limitations.

It has features which may be advantages for rally race in a club setting of course.

But for "wild" off road, the 2.4 frequency has disadvantages which have not been mentioned so far in this thread, and are being played down by equipment makers.

I suggest that you consider 40mhz for offroad and begin to consider 2.4ghz more if you think lots of others are racing very near you as in at a track.
The "old" 40FM reflects off the ground, trees, the sky ...your signal arrives at the receiver from every direction, and it also passes through most objects, features which suits the trick and buggy in particular.

syl77

Remember - 2.4 ghz is direct line of sight reception only.

Some what true, it all depends on how dense the substance is that is in the way.

I fly with the AR7000 Rx (DSX9 radio) which comes with a second mini receiver. The second mini Rx is placed at a different angle to that of the main receiver which helps over the line of sight issue. I have seen many a heli fly out of sight of the pilot (and radio) momentarily behind trees, hilltops and once behind a house, and still respond to pilots input to return back into sight.

Not sure if the car receivers come with these mini receivers, maybe plug will be able to tell us, or even better let us know how he is getting on with his DX2/DX3...

workaccount

syl77 wrote: »

Some what true, it all depends on how dense the substance is that is in the way.

I fly with the AR7000 Rx (DSX9 radio) which comes with a second mini receiver. The second mini Rx is placed at a different angle to that of the main receiver which helps over the line of sight issue. I have seen many a heli fly out of sight of the pilot (and radio) momentarily behind trees, hilltops and once behind a house, and still respond to pilots input to return back into sight.

Not sure if the car receivers come with these mini receivers, maybe plug will be able to tell us, or even better let us know how he is getting on with his DX2/DX3...

My heli has two receivers. One at the back and one at the side. First I've heard about line of sight but I'm new to 2.4ghz technology.

Wonder how the two work though - I mean if it's out of sight then it's out of sight. What good is the second receiver?

FuzzyWuzzyWazza

I use the DX3R, and have had no problems with the buggy going behind objects. The 2.4GHz system works on the same principal as your home network, which works through walls and ceilings, it just depends on the type of material and how big the object is that is between the transmitter and reciever.

syl77

Wonder how the two work though - I mean if it's out of sight then it's out of sight. What good is the second receiver?

If the model goes behind a large dense object then the Rx relies on receiving signals that may bounce of other objects and end up hitting the model. The second mini receiver helps pick up these signals. That is why it is placed at a different angle.

vectra

Have a look >> HERE You might find what you are after

coolwings

syl77 wrote: »

If the model goes behind a large dense object then the Rx relies on receiving signals that may bounce of other objects and end up hitting the model. The second mini receiver helps pick up these signals. That is why it is placed at a different angle.

High frequencies get absorbed much more by objects (in their path) than low frequencies.
Low frequencies penetrate objects better, and bounce better.
That's why you can hear the bass (not the treble) music coming out of a sealed house or car for example.
And why 35FM, and 40FM don't need a second receiver.

T-Maxx

coolwings wrote: »

Low frequencies penetrate objects better, and bounce better.

Is that not contradictory?

Also, like Fuzzy said, 2.4gHz works for my home network, so why would small obstacles in the field be a problem?

vectra

coolwings wrote: »

That's why you can hear the bass

Is it not true that you FEEL bass rather than HEAR it ?

syl77

That's why you can hear the bass (not the treble) music coming out of a sealed house or car for example.

I think this is not a good analogy because you are comparing sounds waves with radio waves. Sound waves are produced by objects, which vibrate rather rapidly. Vetra, that is why you feel the bass..
Radio waves are produced by moving charged particles.

Weather or not a radio wave, reflects, penetrates or is absorbed by an objects depends on other factors rather than just radio frequency alone. Output power of Radio frequency, distance travelled and density of object all come into play.

ARGINITE

Also, like Fuzzy said, 2.4GHz works for my home network, so why would small obstacles in the field be a problem?

What are the walls in your house made off?

Low frequencies are less effected by water and metal.

High frequencies will bounce off metal objects and be absorbed by water [yes even rain can effect 2.4GHz signals]. Microwaves at frequencies of 2.4GHz do not travel well through foliage and solid objects.

coolwings

All at once .... ! :cool:

T-Maxx wrote: »

Is that not contradictory?

Nope .. the comparison is with high frequency which is absorbed by objects.

T-Maxx wrote: »

2.4gHz works for my home network, so why would small obstacles in the field be a problem?

Because low frequency travels better, distance attenuates (weakens) a high frequency signal.
But that is not an issue, the 2.4 is powerful enough for the distance required.

vectra wrote: »

Is it not true that you FEEL bass rather than HEAR it ?

The sense you detect the vibration wave with is immaterial, you detected it, so it penetrated the obstacle. You did not detect the higher frequency at all, with either hearing or feel, so it did not penetrate the obstacle.

syl77 wrote: »

I think this is not a good analogy because you are comparing sounds waves with radio waves. .....Weather or not a radio wave, reflects, penetrates or is absorbed by an objects depends on other factors rather than just radio frequency alone. Output power of Radio frequency, distance travelled and density of object all come into play.

It is actually very good analogy when looking at differences between robustness of a higher frequency, and a lower frequency signal. Which was the thing I wanted to compare.

Of course output matters, but you can't "turn up" the volume of your RC transmitter, so it doesn't matter to us.

Of course the quality of an intervening object matters, but I was talking about a buggy going into depressions in the ground, and concrete pipes which are usually pretty solid.
(Nobody said " what if you stand at one end of the pipe so the signal can go down to the model?" I'm soooo disappointed! )

vectra

coolwings wrote: »

The sense you detect the vibration wave with is immaterial, you detected it, so it penetrated the obstacle. You did not detect the higher frequency at all, with either hearing or feel, so it did not penetrate the obstacle.

What makes you so sure i could not hear the treble as well ?

coolwings

If you can tell me the name of the song, I'll have to believe you ! :-)

vectra

coolwings wrote: »

If you can tell me the name of the song, I'll have to believe you ! :-)

Twinkle Twinkle Little Star

The Doktor

I was fairly certain that 2.4ghz would be good enough for your average rc car.. after all 3g phones ar 2ghz and I certainly cannot see the nearest mast. And Ive seen 38ghz work goin through solid objects.. (not very often though, and not very solid:D)

Sooo.. anyway, i took my futaba 3gr and my phone and went for a walk..leaving the car with my trusty assistant.
The receiver was in the back of the house, all doors closed.
I was able to walk 20m across the road, on the far side of a thick hedge, with two rows of cars (one either side of the road). Then 100m down the road away from the Rx, and down a lane between two houses. I didnt have any problems until i got 10m down the lane at which point it would only respond intermittently. All the time holding the Tx at waist level and my body between the Tx and Rx(pretty dense and thick body it is too!)

Though the reciver is a diversity reciever, which would help.

Also, it has built in fail safe, so as soon as Rx is lost, it stops.
So i dont think there would be many problems with going down a small tunnel, which id be standing at the end of anyway, cos i cant drive what i cant see..