Some interesting Radio Communication bits

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Wrenow

Senior Member
For someone who is a glutton for creating a new product... there is a new radio out of Hong Kong, the Turborix 6ch discussed at length (with some nice photos of the guts, the programming information, etc.) here:http://www.rcgroups.com/forums/showthread.php?t=967207

It is a 6ch 2.4gHz hobby RC radio that is computer programmable with a USB cable (no field programming without a computer). Pretty slick, for USD$42.95. It has already been hacked to program it in Basic from an iPaq. I am betting it could be programmed from a Picaxe, but that is a level or so above my paygrade.

What is also interesting is that the RF modules in the TX and RX are indeed discrete, and merely transfer the PPM signal through.

Hmmm. A pulse datapipe with a decent range (several hundred to 1000 meters in R/C conditions) for USD$42.95 for the complete pair. And it is set up for 5v. Hmmm, what else can we think of that might like a 5v 2.4gHz decent range datapipe with multiplexed receivers? And you get some joysticks, an RC encoder, an RC decoder, etc. thrown in as well. Oh, and a USB to serial cable perhaps? Can yiou pass serial signals down the pipe? Don't know. But you can pass a 6 pulse datastream every 20ms.

For those who don't want the bells and whistles, you can get the same (compatible too) RF stuff in the Hobby King 4 channel (non programmable, very basic) radio for USD$29.95. Me, I would pay the extre $13.

One of the guys in our club has purchased one of the Turborix radios for his ship, and plans to battle it this coming Sunday, weather permitting.

Cheers,

Wreno
 
M

manuka

Senior Member
Wreno: An interesting find. For reasons now escaping me, my extensive RF background has involved very little "hands on" RC work. However I've been following the recent trend to 2.4GHz with interest - the Jan. "Silicon Chip" has a great 2.4 GHz RC model aircraft article in fact. Of course, compared with VHF, 2.4GHz will always have less punch thru' obstacles, perhaps not such a problem for close in floating models or LOS aircraft! Stan
 
B

BeanieBots

Moderator
Does look interesting, especially if there is access to the raw data.
Naturally, all the 2.4GHz LOS issues are not valid when it comes to RC.
If you've lost LOS, loss of radio contact is insignificant in comparison:rolleyes:

The advantages are vast. This technology is a revolution for the RC hobby.
No more frequency checking and vitually immune to noise.
It's like comparing CB radio and mobile phones.

Manuka, with your RF background you really should try out a 2.4GHz RC system. Compare it to a 'regular' system for range and noise immunity. I promise, you will be VERY impressed.
 
B

BeanieBots

Moderator
It will more interesting when useage increases to beyond the 40 Tx units in close proximity. I've spoken to few flying clubs but none have exceeded 23 at any one time yet. More to the point, none have experienced any cross-channel issues, unlike 'regular' systems which will interfere with neigbouring channels under many circumstances.

I have a DMx6 (2.4GHz) and a Multiplex Profi 3030 (35MHz).
Admittedly, the 3030 is an entire class above the DMx6 control wise, but the faster response and glitch-free operation of the DMx6 has me reaching for it everytime I take a heli out. The shorter 6" aerial compared with the old 4' one is real practical bonus too when you need to move quickly.

The only issue I've had so far, is that if powered up in the house, it wipes out my wireless network and often requires a "network repair" to get it going again. I should also point out that my DMx6 is the lower power european version than the ones available in the US.

My eyesight and flying skills are not good enough for 'real' range tests but club members make regular claims of 2 mile ranges which is 'their' limit rather than the radio. (naturally, all LOS and I doubt in the rain either).

For an example of improved response time, check out the renowned Jamie Robertson flying a Blade 400 with DMx6 radio.
http://www.youtube.com/watch?v=-6FZpTxoxZc
Stunts like that require a good radio link as well as a good pilot!
 
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W

Wrenow

Senior Member
BB - my son is the guru here in my household (he also does Helis, planes, cars, Draganflyers, robots including one or two battlebots, boats and subs as well as our model warship-combat ships). Once he tried out 2.4gHz, he noticed a significan difference in glitches and an a much "crisper" response. Once he got a Spektrum DX6i, he has gone pretty much exclusively to their DSM2 format and loves it (though I think the Futaba Fasst system might be technically a bit better, it is also quite a bit more dear, dollars wise). I have used both systems in the harsh model warship comba environment with great success, and am modding a Spektrum DX5e radio for Wes to make the physical inputs the way he likes them and dedicate it to his ship, the Dunkerque.

Nice thing, at the MWC (a bit different format/group of warship combat limited to .177 caliber guns among other things) they actually had 50 ships on the water at once at their nationals in 2008. Granted, some were legacy 75mHz (US surface frequencies), a precious few could have ben 50mHz (Ham) or 27mHz, but I believe the majority were 2.4gHz. Having 50 ships on the water would have been impossible before 2.4gHz with only 40 possible frequencies total available on the other (legacy) bands.

Not so good for submarines (LOS at a bout a foot or so depth or even less in tests), and better to mount the RX (actually a transceiver, of course) high in the ship, like velcroed to the underside of the deck. But they have turned glitchy ships into smooth operators.

One thing, on the decoder with the DSM2 systems (I am unsure on Futaba), the pulses are thrown out simultaneously rather than sequentially as is the norm for legacy systems (after all, with DSM2, it is getting a serial signal and decoding it in the RX with a microprocessor) - this allows all soevos to be hit with their position signal at once without an up to 10us delay between them.

Your analogy of cb/mobile phone is a good one, by the way.

Hmmm. with the Turborix or the Hobby King radios, the RF stage is based on the legacy RF stages like those used in your Profi, and the antenna looks like it could be cobbled to fit. If you flip through the thread, I think you will find some nice dissection photos showing the guts of these two radios and the RF stages. Should you want, you should be able to do an RF stage transplant and turn your Profi into 2.4gHz pretty easily. I am considering doing this with some Vex radios.

Now, to put this back into the Picaxe realm.

Th RF stage is just passing through the standard radio control pulse stream for 6 channels. So we know it can (even if it has some strange error checking protocols involved) can handle 6ea 27-225usec pulses every 20ms, which are applied at the TX end and come out the RX end. It may be able to handle other signals (like a serial stream). Makes for some interesting hack possibilities.

Plus, since the encoder is a serial programmable microcontroller already... starts the creative juices flowing.....

Cheers,

Wreno
 
B

BeanieBots

Moderator
I've seen Multiplex module updates available in the US but nothing UK yet.
The US module would be illegal over here. Hoping Multiplex will bring out an 'official' european version. The simultaneous servo signals is what makes it so responsive. Sadly, the Profi 4000 is discontinued:mad:

I would have thought it should be possible to use any of the 2.4Ghz Tx 'modules' fed with PICAXE serial data. Bandwidth should be pretty damn high as well.
 
W

Wrenow

Senior Member
I join you in lamenting the Profi 4000. :-( Really lusted after one, above my price range and unable to find one locally anyway. Sigh.

Got me started on the Microstar 2000 http://www.mstar2k.com/MicroStar.htm as a project/possible substitute. It is a kind of roll-you-own solution based on the PIC18F8722.

As for conversions for your Profi, I thought XPS had a Euro-friendly model. Loofking at the XPS Profi module, looks like you are in luck,http://www.xtremepowersystems.net/data/Profi-1.0.pdf

Cheers,

Wreno
 
B

BeanieBots

Moderator
Thanks for that link Wreno.
It's been a while since I had a serious look so looks like it's worth looking again now.
 
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