RE: Engine Interference/Noise with Spektrum DX7???
 

I have seen similar glitching on Spektrum car radios when the receiver batteries start to get low. I have also seen it when the transmitter was within about 1.5 feet of the receiver with the car radio.

I haven't had the issue with proximity on my DX7, just a slight buzzing coming from the servos when the transmitter gets too close to the receiver. I also found that my DX7 interferes with my 2.4ghz wireless computer network at home when I have been setting up aircraft, but no noticable interference on the radio.

RE: Engine Interference/Noise with Spektrum DX7???
 

1 foot is kinda close, could be swamping (overpowering) the RX. Try it 4-5 ft next time. Very few people fly 1 ft away.:D Or 4-5 ft for that matter except with some foamies.

RE: Engine Interference/Noise with Spektrum DX7???
 

I was so close to the plane because I was tuning the engine, if I had help I could have had someone else stand further away with the transmitter. But I really doubt me being that close is the problem or would even pose a problem. Im pretty sure just about everyone gets up close and personal with no effects. I just need to do more troubleshooting, but thanks for the info.

RE: Engine Interference/Noise with Spektrum DX7???
 

I have never had a problem with any electric platform (heli and/or fixed wing), but I've pretty much given up using my DX7 with nitro models. I've had 3 models (one model survived 2 crashes, so really 5) go out of control for no apparent reason, all in mild flight regimes (ie level wings, no G's). All where ranged check and control checked before flight. Might be a coincidence or bad luck, but I don't believe it.

After the second one I sent the AR7000 back to Horizon, they said they updated the receiver software and it checked good. First flight with a new airframe (a meticulously built Seagull Extra 260 .9 ARF), same result (loss of signal/control). So I brought the entire wreckage back to my LHS to send back to horizon and tell me what is going on (and check all the components), I've yet to hear back from them. Continue to use it with my electrics with no problems.

RE: Engine Interference/Noise with Spektrum DX7???
 

zaboaa: Were you aware about the RX power/reboot problem?

Did you fix this and take the power requirements into account?

RE: Engine Interference/Noise with Spektrum DX7???
 

opjose what power/reboot problem are you referring too?

RE: Engine Interference/Noise with Spektrum DX7???
 

There was an advisory put out about the DX7 receivers needing specific power levels lest they reboot in flight.

There was a firmware update that is supposed to decrease the boot time so that there is less chance of a crash if this happens.

Apparently 4.8v and even 6.0v battery pack voltage output can drop low enough because of momentary servo draw so that the RX reboots.

Apparently Spektrum now sells a small capacitor to keep the RX charged up during a voltage drop... it is something very similiar to this...

[link=http://www.horizonhobby.com/Products/Default.aspx?ProdID=NOV5626]Click me![/link]

RE: Engine Interference/Noise with Spektrum DX7???
 

It's not just the DX7 receivers. It's all Spektrum and JR 2.4 receivers.

Ken

RE: Engine Interference/Noise with Spektrum DX7???
 

They will generally do this firmware update for free if you send the receiver in.

It also pays to use high quality receiver batteries with plenty of mAh capacity and low internal impedance for less voltage drop under load. If a plane is large enough to handle the extra few ounces, a second battery pack in parallel is helpful. The main thing though is to be absolutely sure your receiver battery is in good condition and fully charged. That means no "quick 15 minute charges" on a wall charger right before flying and periodic checks with a meter that applies a slight load while at the field.

I was not aware of the capacitor being available. I may have to buy a few. Or maybe I will just buy one, to find out the size and rating then pick some up at the local electronics store to make my own.

To be honest, I have never personally heard of this problem happening on sport and trainer type airplanes with standard servos but as you get into high performance digitals on large aerobatic planes, good power supply becomes critical.

RE: Engine Interference/Noise with Spektrum DX7???
 

With all this talk about making sure that reciever battery is always charged to avoid any risks, is it bad to keep the reciever plugged in all the time when I'm not flying? Also is it bad if I do some work on the plane and run the servo's for a little bit(lets just say for about 10 minutes) then I put the battery back on charge. Will this hurt the battery in the long run? Whats some good charging practices?

RE: Engine Interference/Noise with Spektrum DX7???
 

The car is for use in electric R/C stuff like cars and the like. It's not intended to help with the low power problem but rather the noise generated by electric motors. It acts as a noise filter, NOT as a voltage storage device. BAX has stated this in numerous threads in the past.

RE: Engine Interference/Noise with Spektrum DX7???
 

Yah, the more I read about it the more that became apparent. It also is sold in the car section on Horizon's site, not the air section.

They do show it as a means of protection from low voltage though: http://www.horizonhobby.com/Products...ProdID=SPM1600

The cap will store electrical energy and hopefully dampen the voltage fluctuations I suppose. I think so anyhow. Not sure if the effect would be enough to benefit on an aircraft system.

RE: Engine Interference/Noise with Spektrum DX7???
 

The article in the magazine I saw ( where I first learned about this ) had a slightly different looking cap setup, and specifically stated that it was for the DSM receivers to help cure the reboot/low voltage problem.

RE: Engine Interference/Noise with Spektrum DX7???
 

There was another manufacturer that I recall claiming his was better. The one we've been talking about MIGHT take care of instantaneous fluctuations but nothing of the duration we experience in flight situations. A capacitor to store enough energy to be of value would be physically too large for our applications.

RE: Engine Interference/Noise with Spektrum DX7???
 

Yup, you're right...

If I recall correctly the article taked about the small cap being able to handle a small 2 second drop in voltage, but not a complete outage.
The idea was to help prevent the reboot, but the article went on to suggest that a separate or higher capacity battery power source was a much better idea overall.

RE: Engine Interference/Noise with Spektrum DX7???
 

I wonder if it would be twice as good or overkill if you were "OCD" and plugged two of these bad boys into spare ports? But I think for the price its at least worth the added protection. Like some of you have already stated a random high draw of a servo could be just enough to allow the voltage to dip and cause the receiver to reboot, so that's where the stored power in the capacitor would kick in for the moment. On paper it sounds good, but who really knows. But then again it doesn't break the bank so I may just have to get one.

RE: Engine Interference/Noise with Spektrum DX7???
 

There is no such thing as a "free" lunch in electronics. Although small that capacitor will draw a small current and increase your current drain. Best solution - just buy the proper sized battery for your individual system in the first place.

RE: Engine Interference/Noise with Spektrum DX7???
 

I don't think you're understanding me. What I meant was the capacitor is just a extra precaution, no one needs to use connector safety clips to fly, but it sure is comforting to have them. Its a nice-ity not a necessity.