Originally Posted by jpbiondo

I have a question for the officianado's. Is it necessary to mount the antennas on the Optima 9 90 degrees of each other. I had an airplane go in where the controls froze. The model had been flown about 20 times. I was running 4 cell nicad pack. Voltage on take off read 5.1 on the receiver. I flew the plane for about 10 minutes and took it up between 200-300 feet. I started to put it in a flat spin and the plane locked at full throttle heading straigt down. You all know the rest of the story. I did have the reciever antennas mounted on each side of the fuse. They were mounted identically on each side but in the same orienation. I am okay that this was a .60 sized sport plane that I used to test receivers lost at minimal expense. However, I have several giant scale warbirds and a brand new 37% Ultimate. I purchased 8 of these recievers for various airplanes that I have. I needed to find out if the antenna orientation was the potential reason for the lock out. The post mortem review showed 5.0 volts on the battery. BTW range check worked perfect as always pre flight. i could not find anything in the manual talking about antenna orientation. I know that this is recommended on Futaba receivers. Thanks
John

On my 9 channel, I put the antennas at 90 degrees.

The Optima series of RX's does not need multiple antennas because of the BODA, orientation is not critical but 90 degrees is the rule of thumb for maximum performance.

Was there any beeping prior or during the loss of control? What type of battery was used and what servos? How did you test the voltage... with the telemetry? What did it go down to when you wiggled all the sticks quickly? It sounds like a brownout situation. Use of the SPC feature with only a small 2S lipo would eliminate this possibility in the future. Or, if you run a single battery for RX & Servo, it is wise to use a 5 cell NiMh.

Where do you live?

Mike.

Hi, I also have hitec aurora 9x with optima 9 receiver. Now i plan to buy a power panel for my new katana s. However, I dont know which power panel should I pic? By the way the servos are high voltage 7.4 servos. Which power box is compatible with my receiver and servos? Thank you.

Hi. Let me put my two cents in. If you had digital servos you might have browned out using a 4.8V pack. The main reason the manufacturers have gone to high-voltage receivers is to give them more headroom on the receiver bus. No matter how you look at it, the standard R/C plug is a terrible plug for conducting high currents. On top of that, the peak current you read on a meter for a servo is really about 1/2 the actual peak current. The servo pulses the motor, its never fully on. At a 50% drive rate (which is fairly common at peak torque to avoid burning up the motor) if you read about 4A on the current meter you would see about 8A peaks on an oscilloscope. The meter averages the fast pulses. Digital servo put a huge strain on the receiver bus.

The other thing is antenna placement. 2.4GHz is not a great choice for us to be flying but we are stuck with it. The radio waves at 2.4GHz do not bend around things like 72MHz did. On gas planes, the motor can completely block the radio signal to the receiver. I have found you really have to look at your antenna placement carefully to be sure that from practically every angle at least one antenna is not blocked by anything metal in the plane, gas engine or turbine. I have had jet guys tell me they were loosing signal flying away from them. When I looked at their antenna placement both antennas were completely blocked by the turbine from the rear of the plane. On my IMAC planes I now make sure one antenna goes up into the canopy as high as I can get it. On most gas planes the engine is down or the mufflers are down. Putting one antenna down and the other across is horrible. The other thing, and I know the radio manufacturers are going to yell at me, is I really have no idea how well the software in the receiver is tested. There is a lot of computer code in the receiver now to handle the 2.4GHz protocol. There are a lot of conditionals and test loops. If you don't test your code so that all branches are tested under all conditions you can find you missed some place where the code gets stuck looking for something and ignores everything else. I have basically given in to the fact that there are going to be unexplained losses due to link failures. It may be 1 in 10,000 or 1 in 100,000 but they are going to happen at 2.4GHz. It was not an issue with PCM because that was all hardware and had very simple recovery. Even if you browned out the PCM receiver you would recover as soon as the voltage came back up. With 2.4GHz you have to reboot the microcontroller, reconfigure the radio receiver chip, start hunting for the transmitter ID and the hop sequence. Its very, very complicated.

Originally Posted by jpbiondo

I have a question for the officianado's. Is it necessary to mount the antennas on the Optima 9 90 degrees of each other. I had an airplane go in where the controls froze. The model had been flown about 20 times. I was running 4 cell nicad pack. Voltage on take off read 5.1 on the receiver. I flew the plane for about 10 minutes and took it up between 200-300 feet. I started to put it in a flat spin and the plane locked at full throttle heading straigt down. You all know the rest of the story. I did have the reciever antennas mounted on each side of the fuse. They were mounted identically on each side but in the same orienation. I am okay that this was a .60 sized sport plane that I used to test receivers lost at minimal expense. However, I have several giant scale warbirds and a brand new 37% Ultimate. I purchased 8 of these recievers for various airplanes that I have. I needed to find out if the antenna orientation was the potential reason for the lock out. The post mortem review showed 5.0 volts on the battery. BTW range check worked perfect as always pre flight. i could not find anything in the manual talking about antenna orientation. I know that this is recommended on Futaba receivers. Thanks
John

Hi. If you want to run high-voltage and have all high-voltage servos then you should look at our PowerExpanders. They do not regulate the servo voltage like the PowerSystems do. Other than that you just need to look at the features each PowerExpander has and decide what features you need. Ask me more questions or call us.

Originally Posted by goktu

Hi, I also have hitec aurora 9x with optima 9 receiver. Now i plan to buy a power panel for my new katana s. However, I dont know which power panel should I pic? By the way the servos are high voltage 7.4 servos. Which power box is compatible with my receiver and servos? Thank you.