Fly-dream RX\Fly-sky TX
I want to post a thread on the version 2.0 Fly-Dream 2.4 GHZ TX module (JR in
my case) with the 8 channel RX married to the Fly-Sky FS-TH9X transmitter
for the purpose of getting posts on this equipment and it's success or not.
I have been flying XPS and Spectrum DX6I for the last 3 years with no problems
on either. But, I decided to try some chinese flavor, so I looked at all the options
and decided if FLy-Dream had failsafe it was an obvious choice due to
the $20.00 per RX, and $41.00 for Module and 1 RX.
After getting the wrong RX's (V 1.2) with V2.0 module and getting 3 more sent
with the right version, I got them bound and working. Here is what I found:
1. very small 8 channel RX weighing 6.5 Grams with very good construction.
2. Dual antennas with length options of 4.5", 6" , and 10" (approximate).
3. Range check with no antenna and TX pointed at plane (10" above ground)
the range was 256 '. Looks to be more than enough. (they say 1200 meters)
4. The module fits the Fly-Sky TX very nicely, with the antenna on top of
the module which gives good protection being behind the handle.
5. A nice surprise was the current drain on the RX. Only 20.8 mils (no servo)
XPS 8 RX draws 69 mils (TX on), the spectrum draws 96 mils. (TX on).
6. With bench supply and DVM I measured drop out at 2.4 V. and when
bring the voltage back to 2.5 V. reboot was very quick, about 1 sec.
7. I really like the co-ax antennas. Tape one fore and aft to the side and
one vertical and no worry about servo cables getting too close to the
8. Operation of all 7 servos is very smooth, no hesitation anywhere, and I
can see no delay in elevators using ch. 2 and 6. Both elevators appear
to come up together without a lag. Not true on my Spectrum (older
9. The support from Fly-Dream has been very good, although we have
trouble communicating, I get emails back the next day on questions.
10. And very importanty, a good failsafe system. After bind, with led lit
and receiving, press the button on the RX, hold, light goes out, set
controls where you want them, press button once and that's it. It
works from then on going exactly where you set it on loss of signal.
It so easy to set up a cave man can do it.
11. Touching the TX ant. to the RX ant. I got swamping at 1 CM.
Here is how the system works according to Roma at FLY-Dream:
The TX picks 3 clean channels (frequencies in 2.4 spectrum). It transmits
each packet of data on all 3 channels constantly. The RX is told which 3
(at boot up), and receives on the 1st one until interference is detected.
(probably by CRC check or data comparison or both that isn't clear). Upon
interference or noise it goes to the next one and the 3rd one and back to
the 1st one.
Having 3 RX that are useless (the V 1.2), I decided to tear off the cover
which BTW is very heavy and hard shrink of some kind, and see what was
inside. Both the Module and The RX use the TI CC2500 Rf chip with RF pre
amp T212, and 32 pin Atmel processors. 1 in the RX, 2 in the module.
All in all I think it is a winner. I would add a button to decrease pwr for
range check. otherwise, I see no other negatives. Hope to hear from someone
on this system. BYW I got mine from www.hobbiesbp.com
Last edited by surfmount; Feb 03, 2010 at 09:08 PM. Reason: reformat
Yes I can agree the system is in my eyes the best system available, in range of 20 dollar receivers. (price is very important to me, as my Airtonics works well but receivers are too expensive especially for foamies etc)
I have been flying the 4 channel recently. Range is really good, far much better than 450m. When walking away testing the range I was getting so far and it was still working that I decided to walk back. I do nut understand why 450m is stated and 1200m for the 8 channel, the chipset and rf stage are identical.
4 channel is really light and compact, but 8channel is also really light too!
Binding is flawless, switching on off the tx and rx is online within one second. I did not have found any problem of jitter, or spikes. Also I did not see any problem with transmitter at close range.
When flying my plane with the small receiver it reacts good and never find a spike. or problem.
To set the failsave simply push the button during startup, than when led goes off loosen the button, set stick min position you like and push the button on receiver failsave for all channels are set and stored until you repeat the procedure.
Technically the system seem using some chinese 2.4ghz modules as you'll also find them in Corona, Wow rc, Frisky, etc. On top they are using atmel cpu, 2 in tx 1 in rx. Likely each RC manufacturar implements it's own coding schemes and use of the modules.
Only 3 comments I have:
1) The diversity of the both antenna's on the 8 channel receiver are not monitored and not switched by RSSI or by bit error rate from the cc2500, they are just coupled with a simple capacitor in parallel, wich means some losses due to fase erros and impedance mismatch.
On the the other side I checked inside my airtronics receiver and I see the antennas are also put in parallel, but in this case with impedance adaptation network.
So I am not sure if putting antenna's in parallel is a bad or good thing.
All I can say no range or lock out problems sofar.
(In theorie it should be simply possible to equip the 4 channel receiver with dual antenna's, so it should also make 1200m)
2) They provide a buffer capacitor to prevent for spikes noises from servo's etc. this capacitor has to be put on a free channel. I don't like it as the capacitor is big but also it does not buffer very well, as it also powers the servo's wich will pull the voltage down. The Capacitors in the receiver ar very small, I think when you use clean servo's and speed control you can just live with it. But I think a few ms voltage drop, below 3v might lock out the receiver.
When opening the receiver you'll find the +5V first pass a diode, for polarity protection, than there is a 3V3 regulator and small smd capacitor.
I soldered a panasonic "goldcap" storage capacitor. They are normally used in back-up circuits etc. 0.1F 5.5V.
With this capacitor, when disconecting the battery the receiver will stay on for almost a second. It makes it totally proof to any noises on voltage.
3) The regulator used in the TX module gets warm, it is not of any problem or risk, but means waste of battery life. 12v is regulated down to 5volts, there after a 3v3 regulator feeds the TX module. Best would be to use an efficient 3v3 switching regulator.
In my case I build the module into my rds8000, and feed with 3v3 from the regulator in my RDS8000
Anyway the system works flawless sofar and I am happy and can recommand the system!
Yes, Fernandez, I like your .1 f. cap for a 5 Volt system. Surely will help stop
drop out. I think I mentioned in my thread that I tested the RX down to 2.4 V.
before dropout, but even then the cap would help. I use only 6 volt systems
so you have another 1.2 V. nominal "head room". Also, this season (if it ever
gets here) I am going to Life04 cells. Two cells saves two ounces and they
hold their l4 milliohm ESR clear through the charge, unlike both Nickel types.
I think that will help dropouts tremendously. I tried a 1 farad (big & fat) and
I didn't get a 1 sec hold on turnoff. Maybe not as good as your Golden cap.
I haven't flown my Fly-Dream yet, but I am glad to hear that you have success-
fully. Have two installed in gas airplanes.
Last edited by surfmount; Feb 03, 2010 at 09:03 PM.
this will Convenient.Thanks!
Different radios on 2.4 are NOT mutually compatible. The only exception is when they share technology (JR/Spektrum) or are really the same radio with a different label (Turnigy, iMax, etc.).
FlyDream is a distinct manufacturer and their modules work only with their own receivers.
Note, however, that the FlyDream modules come with one receiver for $39 and extra receivers are only about $21. So maybe it doesn't matter.
I'd go with the FD DIY module and replace the HK one. I think HK only uses 3 frequencies anyway. And the receivers are nevr in stock. They you would have receivers that would work with both transmitters. Just a thought.
Last edited by Chomamma; Apr 01, 2010 at 10:14 PM.
What convinced me was seeing that FD V3 is a true frequency hopping system. For proof, see:
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