JR-9303 2.4 Field Results

[1bwana1]

Now that the JR-9303 2.4 radio systems are shipping, I thought we should have a thread to share our experiences and setups. I have heard that they are already sold out of them, so there should be a lot of you out there that have them. I have been flying 2.4 on my small planes for about a year now, but have been using my 9303 PCM in my giant scale planes. I am a big fan of the 9303 because of it's features, programming, and feel, so I have been anxiously awaiting this release. I'll start the thread with a brief report.

A friend of mine received his 9303 2.4 this week. He decided to install it in an older 42% Radio Craft Extra 330LX as a test bed, because, he says that plane owes him nothing at this point, and he won't feel too bad if he losses it. This is a large heavy (43lb +) plane, with a DA-150, a 30 X 12 CF prop, and both smoke and gas tanks. I believe he said that the plane has 18 digital servos. This is a challenging environment for any radio system, so it makes a good test bed. Having some experience with 2.4 systems, I was very skeptical when I saw the installation. Basically, he had just removed his old PCM RX and replaced it with the JR-921 2.4 RX that came with his radio. The main RX was buried deep in the fuse, and in contact with a lot of wires. The satellite RX was mounted close by, and up a little. In a plane of this size I would have added an additional satellite RX as high up in the canopy area as possible to maximize diversity. The system is powered by two 4800 Fromeco LiOn batteries, two switches, two regulators set at 6 volts, with each regulator having it's own lead into the RX. I warned him that this was a pretty crude install, and I was a bit concerned. He wanted to continue any way, so we did.

We tethered the plane, started the motor, and he went about 200' away with the range test button pressed with a perfect solid connection. I then untethered the plane and began to rotate it about 10 degrees and tested again. Sure enough there came a point in the rotation that the RX were blocked by the motor, prop, and fuel tanks, that we lost connection. We noticed that he had the antenna pointed straight at the plane, which put the plane directly in the antenna null. Once we re-orientated the antenna we had a solid connection at all angles on the plane. We had a good range check at about double the recommended distance so we decided to fly it.

We flew the plane 3 flights with great results. We loaded the servos as much as possible, we flew far away and very high, we flew low a hard. The system worked perfectly. We asked each other if we noticed the rumoured higher response rates. Since this isn't a plane that is flown often we could not be sure. However we both agreed that we did feel very locked in and the plane flew perfect, and we agreed that it had a smoothness that we didn't notice with the old radio system.

My friend has decided he has enough confidence at this point to do the next test in one of his "first line" planes next. He will take the precaution of using a power expander to ensure that the voltage to the RX stays above the re-boot level, he will also install one additional satellite RX, and the data logger so he can optimize placement of the RXs.

All in all, a very good result. I hope it all works out to be as solid a system as it is advertised to be. If it does I will have one soon myself.

Let's hear your results.

-STEVE-

[3ddd]

what is the low voltage cut off on the jr radio?

[1bwana1]

3ddd,
The issue is not the radio, it is the receiver. I believe the receiver cpu will re-boot at voltages lower than 4.7 v. When this happens it takes between 4 and 10 seconds before you re-gain control of the plane. This is a long time, and will most often result in the loss of the plane. When you are using a lot of high torque servos it is very easy to draw the voltages down this low if you don't design a system to make sure it doesn't happen.

[dick hanson]

The reset on rx -off to on- can be under one second - I have tested this numerous times
This is a "reset" where the signal is good but the power to the rx is "dropped " a situation involving about 3.5 volts or less .
IF you shut off signal -then the reset can be from a second or so - or much longer .
Two completely different situations. Tho of course, the rx must reset as for battery power - there are many opinions - for my money - nothing beats a direct battery approach-less parts
If you choose large, low impedance NiMh or A123 cells you are in good shape either will withstand huge loads n spikes with nothing to heat up .

[3ddd]

i new the reset voltage is in the receiver and 4.7 volts is my point .no radio should be sent out to the public with a limited voltage range like this.most people will think the 4.8 pack that is sold with these radios is ok when in reality they are well below exceptable.i have seen first hand as an instructor at our field when a helo is flown below the voltage requirements.quite costly,very quickly,but it was the battery that came with the radio.why would they sell me a battery too small?some people just don't grow with more responsability and learn.not fightin just my thoughts

[Eury]

	Quote:
	i new the reset voltage is in the receiver and 4.7 volts is my point

No, it's 3.5 volts, FAR lower than 4.7. If you are using packs that can handle the loads you are putting on them, and you keep them charged, you'll never reach that. The pack that comes with it is fine for some applications, I'd put it in a 40 size plane with 4 servos without a second thought, anything bigger than that (and certainly on a heli, that battery is WAY too small for a heli, Spektrum or not) and you need to use a better pack. It's not JR and Spektrum's fault that people don't set up their equipment properly.

I have 8 flights on my 9303 so far. 4 on my 33% Composite Edge with dual AR7000s, and 4 on my 35% Extra with a single AR7000 on a power expander. The flights were all flawless. I personally don't put a receiver into a giant scale until I've tested it in something I don't care about, so I haven't flown the R921 yet, but I'm going to put it into an Ultra Stick in the next day or so to test, and then it'll go into the Extra.

[3ddd]

i tried to find the specs on the 9303 receiver voltage but i couldn't find it to double check what i was told so till then you are right,haha.i really don't care much i just hate to see people loose aircraft they saved to buy,build to a bad radio setup from the factory

[Eury]

I would say that if you are so inexperienced to put a 4 cell 1500mah in a giant scale or a heli and you lose the plane or heli, you had no business flying that plane or heli. A 1500mah 4 cell is not an unusually small pack for an included battery, in fact, it's pretty large, my Futabas always came with 1100mah packs. JR/Spektrum is not responsible for people not knowing how to setup their equipment.

[3ddd]

i never said they were but they darned sure didn't publish the fact that their receivers rebooted at too high a voltage for sometime.and a lot of people buy and use what the lhs recommends and they all don't know what is best.i don't remember saying anyone used this in a giant scale plane but alot of people use them in there stock heli's.as far as your statement on futaba radios.i have a brand new futaba 9c and the radio trans had a 700 mil and flight pack is a 600 mil so you are wrong on that point

[Eury]

	Quote:
	as far as your statement on futaba radios.i have a brand new futaba 9c and the radio trans had a 700 mil and flight pack is a 600 mil so you are wrong on that point

OK, so Futaba packs in worse stuff than I said? Their heli radios come with bigger packs than the airplane radios. The point is, if someone uses correctly sized batteries, there is no issue. Blaming Spektrum because LHS employees are recommending the wrong equipment is crazy.

[1bwana1]

One thing I forgot to mention was the ease in making the switch. Just hook up you old JR-9303 to the new JR-X9303 2.4 and use the transfer function. All your programming and mixing moves to the new radio. Then just plug your servos into the same channels and you are ready to fly.

I do not want to be rude to the guys who want to discuss the merits of different brands or systems, or debate the merits of the boot up voltage of the JR 2.4 RXs. There are a lot of other threads that are actively discussing those things. I would really like to keep this thread focused on those who have the new radio, and their experiences, and setups. This would include both successes and failures. I think we would all get a lot out of that. Again, I am not trying shut anyone out, just keep an easy to follow targeted thread.

Thanks Guys!

-STEVE

[Mudsurfer1234]

Here's a newbie question, what's the resolution like on the 9303?

Is it better than 1024 PCM on 72 MHz? as in higher resolution (not response time)