Understanding Spektrum and Futaba Low Voltage Claims

[Nelvick]

I dont know if was posted before but here we go.

The technical director explain how works the ligths on the spektrum recievers and its a good tip for everybody.

YouTube - Broadcast Yourself.

[Judge]

I just tested several of my R617FS receivers that are linked to my 6EX. Funny, on my 7 channel R617FS receiver the light turns green essentially instantly when I turn on the RX switch. Same with my R6004FF receiver. Clearly they are using an older Futaba receiver and not one that is currently being sold.

He said they were using a Futaba 6 channel RX and I suspect it was one of the older first generation receivers (R606FS) that did take a couple of heartbeats to re link when turning on power. It is not one of the new 6 channel receivers since those have end plugs.

The Futaba 6008HS or 6014HS receivers also turn on virtually instantaneously.

It would have been nice to see him use a currently available Futaba receiver, but in either case, the receiver comes back pretty quickly when power is restored.

He also failed to mention that Futaba has a feature that will tell you if your power has dropped below 3.8 volts, where he started the test. This is from the 6EX-2.4GHz manual (the radio he used):

	Quote:
	Battery Failsafe Your system provides a second safety function called Battery Failsafe. When the airborne battery voltage drops below approximately 3.8V, the battery fail safe function moves the throttle to a predetermined position or fast idle, if you haven’t set it. If this happens, you should immediately land! If you need to increase throttle for your landing approach, you may temporarily reset the failsafe function by moving the throttle stick to idle, after which you’ll have about 30 seconds of throttle control before the battery function reactivates.

[cjcyclesrc]

Great Video.

[ferocious frankie]

Just an observation, when he gets to 3V, even though the servos stop functioning, the light on the Futaba RX stays on, while the light on the Spektrum RX goes off.

[Nelvick]

As mention in the youtube comments, he cannot warranty if both servos are identicals, and i agree with Judge that do not was a good test because are not both the last technology of each brand. Will be interesant see that with a JR921 and a one of the futaba with the same amount of channels.

Without mention that probably they have the last firmware in the AR7000. My AR7000 take a lot of more time to bind again. I know horrizon can upgrade that for free but...

[cjcyclesrc]

That Spektrum Fast Connect firmware came out in July of 2007.

When did the 7C 2.4Ghz come out?

[dougpeck]

Thanks for the info... very informative... !

[Judge]

	Quote: Originally Posted by cjcyclesrc
	That Spektrum Fast Connect firmware came out in July of 2007. When did the 7C 2.4Ghz come out?

Not sure but it does not apply here since he is using a 6EX radio and a 6 channel RX. Any and all currently available Futaba FASST receivers will turn on virtually instantly. Also, as noted above, notice that the green link light on the Futaba does not go out below 3 volts, what happens is the servos no longer work because almost ALL servos use a 3 volt signal voltage so it is no surprise that both systems stopped at 3 volts, because that is the minimum voltage that the digital servos will work at.

[cjcyclesrc]

	Quote: Originally Posted by Judge
	Not sure but it does not apply here since he is using a 6EX radio and a 6 channel RX. Any and all currently available Futaba FASST receivers will turn on virtually instantly. Also, as noted above, notice that the green link light on the Futaba does not go out below 3 volts, what happens is the servos no longer work because almost ALL servos use a 3 volt signal voltage so it is no surprise that both systems stopped at 3 volts, because that is the minimum voltage that the digital servos will work at.

I just glanced at the radio and thought it looked like a 7C. I looked again and it's not one. Both RX's seemed to work until the servo quit.

[sgillmore]

I'm so tired of this debate.

I really wish everyone would just use whichever radio makes them happy and quit trying to convert the other side. I can't vouch for every 2.4Ghz system on the market, but I think most of the name brand stuff works just fine. Me...I'm a loyal JR/Spektrum user and all my radios have been flawless throughout the years from 72 to 2.4. However, Futaba also offers great equipment and has for many years. I have lots of friends that fly Futaba and love them. To each his/her own.

The truth is, we all should be taking precautions (even back in the 72Mzhz days) to ensure that our batteries don't fall anywhere close to 3.5v under load. That can be a challenge in the age of giants with 8+ 200-300oz servos, but it's vital. Personally, I'd don't care what my RXs do below 4.5 volts, because it will never happen.

[Judge]

	Quote: Originally Posted by sgillmore
	I'm so tired of this debate.

I did not see this as a debate, I actually think that the video was a good demonstration of the two systems. The take away is that both radios work right down until the voltage is too low to drive the signal to a digital servo (3 volts).

I like that Futaba has a warning for that well before you get there (battery failsafe), but in the real world anyone who gets their RX pack that low is looking for trouble in the first place.

[sgillmore]

	Quote: Originally Posted by Judge
	I did not see this as a debate, I actually think that the video was a good demonstration of the two systems. The take away is that both radios work right down until the voltage is too low to drive the signal to a digital servo (3 volts). I like that Futaba has a warning for that well before you get there (battery failsafe), but in the real world anyone who gets their RX pack that low is looking for trouble in the first place.

I also thought that the video was a good demonstration. Although the presenter was a little biased towards JR/Spektrum. To me it, it just reinforced what we already know...don't let you battery voltage drop below 3.5v or especially 3.0v. Both systems quit at 3.0v, both recover quickly. Regardless of the versions being tested, the difference was negligible (IMHO).

[jamesrxx951]

i thought the demo was very interesting. even though he was a jr guy it didn't seem biased. both systems worked about the same. he did mention that the spektrum was alittle faster on boot up but really was a very small difference. and from the sound of it the new fasst stuff is faster yet. even though the servo's were working on 3v kinda makes you wonder how much power they even make at that low of voltage. rule of thumb on any system carefully calculate your power needs.

[Paul5992]

I would like to comment on this. I started out in 2.4 with a 6ex. I wanted to wait until a reputable company came out with 2.4..... Spektrum? Who the he!! is spektrum? Is what I was thinken. With 606 rx's. It worked perfectly. Until I upgraded to a 9c with an 8 channel module and rx. The module I found out after I bought it was not compatible with the 606 rx. I called futaba and asked what i was supposed to do with the 6, 606 rx's that I had. They told me that I was SOL!!! The 606 is only compatible with the 6ex. I WAS MAD!!! I sold ALL the Futaba radio gear I had and went with JR. And have never regretted it. So here is my point. It is a fair comparison to say the Spektrum AR7000 reboots faster than a 606 because a lot of guys still have the 606's and swear buy them. I loved mine. But the JR/Spektrum stuff is a better deal to me.

[Judge]

Sorry, but something is wrong here. The 608 is fully compatible with the TM-8 module.

http://2.4gigahertz.com/modules/modules-receivers.html

In fact it is exactly the opposite, the R608FS is NOT compatible at all with the 6EX-2.4 FASST. So I think there was some sort of serious miscommunication here.

Are you perhaps thinking of the older 606FS, that one did only work with the 6EX.