sass25479

My Feedback: (9)

We sometimes get fast moving thunder storms. A flying buddy of mine was flying with a 72 Mhz radio and a storm came through so quickly that it was on top of him before he realized it was so close and he could get his plane on the ground. Each time there was a lightning strike his receiver went into fail safe.

His question to me was, "Would Spektrum be affected the same way as his 72 Mhz radio?". So how about it, does anyone know the answer?

BarracudaHockey

My Feedback: (11)

I'd be more worried about the lighning hitting me than interfering with the radio.

fizzwater2

My Feedback: (61)

lightning covers a pretty broad electromagnetic spectrum, and it could conceivably interrupt even a spread spectrum 2.4GHz signal.

But - I agree, I'd be more worried about being hit by the stuff.. and landing in a hurry!

JIMF14D

Well the antenna is shorter so maybe you could risk your life for another minute of flying? Iwould hope you would not take such chances under any conditions.

I think this question takes the cake for 2011 !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! At least he is not Hitec guy........

sass25479

My Feedback: (9)

My first comment to him was stupid don't fly when there's a storm. He explained that it had been just cloudy until the lightning started. I'm not saying that we want to fly with lightning, just a curiosity if 2.4 GHz would be as susceptible to interference.

sass25479

My Feedback: (9)

Why would this question take the cake? I'm stupid for wondering if 2.4GHZ would be more robust? I posted here in the support forum hoping for someone from JR to answer a technical question, not to get flamed by someone who probably dosen't even understand the theory behind the radio.

BarracudaHockey

My Feedback: (11)

True its the "JR Direct Support" forum but its become something of a free for all since Danny's job kept him from being able to cover questions here.

The answer is the same as with most other sources of RF noise. It's much less susceptable to RF interference and it uses a system of packets that if the entire packet isnt valid its ignored so you dont get traditional "glitching", that said, nothing is fool proof.

I wasn't being a smart butt in my first reply, having seen someone that had been hit while I was fire rescue, if there was any possibility of lightning in the area, glitching would be the least of my worries.

duworm

Interesting question. I am glad someone asked it.

There is a perception by many in RC that interference is interference and if it affects one type of system it affects them all. Fortunately for us, that is not true.

On 72, there is a possibility that lightening could cause an uncommnnded servo movement, but very little chance. (AM vs FM vs PCM and a bunch of other stuff)

AM, is within the RF of a lightening splash that will momentarily interfere/block the signal until the splash dissipates. Lightening splash here might cause an uncommanded servo movement but it would be of a very short duration.

FM is a little higher in the RF range and will be affected by a lightening splash, but only if is close enough. The interference here is very minor in comparison to AM.

PCM for lack of a better word is digitalized FM. If close enough, lightning splash may momentarialy block a signal, but an uncommanded servo movement should be next to impossible.

Lightning splashes don’t normally cause much on interference frequencies above 2Ghz. Local TV stations rarely see any interference from lightning splash on 2Ghz analog video equipment unless the lightening is VERY close. On 2.4, even if the splash is VERY close, the receiver may only be temporally blinded (the data packets are corrupted). The receiver continues to send the same packet stored in a temporary buffer to the servos until a new uncorrupted packet is received. The packet must contain the codes necessary for the receiver to accept and decode the signal. A lightning splash cannot manufacture a bind or decode code. Short version, RF interference, any RF interference cannot cause an uncommanded servo movement in 2.4.

At most, the servos hold in their last position unless you have failsafe set. Upon reacquisition, the control returns.

I hope this helps.

Sherman Knight

ddaveb

FM is not higher in the frequency band it is merely a type of modulation were the modulation or data signal changes the frequency of the carrier signal in sympathy with the data were as Am changes the amplitude of the carrier signal in sympathy with the data signal. It is true that Fm is more immune to electrical interference as most electrical noise appears as spikes on an Am signal & so can corrupt the data signal on Fm the signal is clipped & so losses most of the noise element. As regards 2.4ghz signals ,2.4ghz is in theory out side the frequency range of electrical noise which is about 700mhz so should be immune to lightning interference . Dave