True range of RC signal
 

Hi Guys,

I am trying to find info on the true range of the RC signal from normal transmitters to an RX in the air. I am looking at flying at a site exactly 3 miles from an existing RC club. We fly large sailplanes, and they can be flown surprisingly far from the pilot on the ground in search of lift. I am concerned about the issues of channel conflicts between the two fields.

Does anyone have some data on this?

TIA

Lee

RE: True range of RC signal
 

The general rule is that you want to be at least 2 miles from a unit on a competing frequency. This means that if you want a margin of safety, and you are planning to get 1/2 a mile away, you would want to be 2 1/2 miles away from the other transmitter.

RE: True range of RC signal
 

You need to make sure that the transmitter and plane needs to be 2-3 miles away. So if the two potential flying areas can overlap, then you need more distance. If the areas are back to back then 2 miles will be OK.

RE: True range of RC signal
 

specs for most Rx's say there operating range is about 5000 feet. Thats about 1 mile. If you are at least 2+ miles you shouldnt have any problems. But as above if you fly towards that field you may encounter problems at the outer ranges

RE: True range of RC signal
 

If you are farther from your airplane than the potentially interferring transmitter, your plane will probably receive him better than you; equal interference.

Les

RE: True range of RC signal
 

To be on the safe side, and not have to worry or take a chance....

Have you ever thought about visiting the "other" field, seeing what channels they use the most, and then trying to work out some type of frequency agreement....?

RE: True range of RC signal
 

i know of two sites that are 2.8 km (a hair less than 1.75 miles) apart with no obstructions other than a couple of trees and they have no probs. one site has mostly glow powered models and helis that that aren't flown too far away but the other site is for gl*d*rs that can get quite high and wander towards the other field.


dave

RE: True range of RC signal
 

Three miles is around 15,840 ft. For the most people, maximum visual range is less than 1000 ft. I have seen Curtis Youngblood auto from 2000 ft, so let's use that number.

If you fly a model as close as you can to the other field, it will be 12,000 ft. from that field and 2000 ft. from you. Signal strength reduces with the square of distance, so any interfering signals from the other field will be (2000/12,000)^2 = 0.027 of your signal. Thats a difference of -15 dB. Interference would have to be about 10 times stronger before your receiver would notice.

If you restrict yourself to no more than 1000 ft. in the direction of the other field, then the difference is -18 dB. That 3 dB extra means the interfering signals will be relatively half as strong as they were when you were 2000 ft. away.

You would have to be flying about a mile away in the direction of the other site before you noticed any effect. At that point you would mostly be in control, but will get hits or holds (depending on whether you're using PPM or PCM). If that happens, just turn back towards yourself.

RE: True range of RC signal
 

Phil,

If you could not see Curtis' helicopter (mvr less 1000 ft) how did you know he was 2000 ft when he initiated the auto...? Did he have a Mode C on that thing....? Or is you guys sight so superior to the average persons that you could see it at twice the normal person't vision.....?

I have to disagree about the "most peoples" maximum visual range is less than 1000 feet....

Sorry....couldn't resist....:)

RE: True range of RC signal
 

Well, I could see the smoke cloud and he had it in a continuous pirouette. I could only determine the attitude (inverted or not) from the way the tail appeared to turn. No one there could actually see the attitude directly until it was back down somewhat.

As to knowing how high? I asked him. Maybe he exaggerated a bit. Does it matter? I've seen others go to 1000 ft. It's easy enough to estimate the distance by counting the time between the smoke disappearing and the engine going quiet. Sound travels at 1100 ft/s.

None of this is accurate, but it's good enough to show that three mile separation of flying sites is more than enough.

RE: True range of RC signal
 

Thanks guys.

You might be surprised at some of the altitudes and distances we fly the gliders at.

RE: True range of RC signal
 

i was allways suprized how you guys see these things, cause i see the gliders they go so high up, controlling them too, you guys must have eagle eyes. But it could me too i do have poor vision.

RE: True range of RC signal
 

Did "gliders" suddendly become one of those words the FCC is trying to ban since the wardrobe malfunction?

RE: True range of RC signal
 

I could easily see my Stinger at 1200ft according to the altimeter. We are only 50 or so ft above sea level probably could have seen it another 800ft