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-   -   Transmitter Range (https://www.rcuniverse.com/forum/rc-jets-120/11600419-transmitter-range.html)

Justflying1 06-18-2014 12:45 AM

Transmitter Range
 
Does anyone know what would be the range of a high end brand radio. No Specific name war needs to be started and as a matter of fact I don't want any brands mentioned.

Would say 4 km be realistic before you loose contact. Obviously you will not see a plane at this distance and I sure not interested in flying anywhere close to that but I am curious and I get asked the question every now and then.

ticketec 06-18-2014 01:29 AM

I've done a little bit of "in flight" testing on this while FPV'ing.

Using a white coloured 1.2m span slow moving model I was able to see it up to about 1.2-1.3km away, but that's only if I watched it all the way out. After about 700-800m it is almost impossible to look away and find it again in any reasonable amount of time. working out which way it's going was pretty much un-achievable either. so that's roughly how far an average person can see a model.

In terms of radio distance, I believe that the 4km figure came from a MAAA (Model Aircraft Association of Australia) requirement as the minimum safe distance between 2 model fields not in contact with each other during the 36mhz days for interference reasons. Your radio would never transmit that far.

I also did some testing with this using the FPV setup for aircraft control range, again because it A: has GPS data live so I can see how far away I am, and B: if I lost signal, it has automatic return to home, so no risk to the model or bystanders etc, and C: you also have a R/X signal strength indicator (RSSI) being displayed as well. There was also a lot of discussion about this very topic on the FPV forums when it started being popular a few years ago.

I found that you would only get solid signal using 2.4g (only tested 2 brands) anywhere in the region of 700m-800m away, before it started having issues, I.e aircraft not responding all the time to inputs, so lots of lost frames at any one time. But the answer is nowhere near as straight forwards as that.

2.4g range is very susceptible to is surroundings. The amount of buildings, trees, other 2.4g xmitters around etc. even the weather can play a factor in the ultimate distance you can achieve. the number of antennas/ satellites and placement also play a major factor. I know you don't want brand names named, but there was variance between the brands from what other people were posting on FPV threads. frequency hopping seemed to do a little bit better distance wise, but not by a massive margin. I think people were getting 1.2km out of large name brands that frequency hopped. My testing was done with only one satellite, in a pretty built up area with plenty of other 2.4g noise around, but even with those factors, it seemed to be roughly the accepted safe distance most people were able to acheive.

Funnily enough it was a cheap, relatively unknown brand that got miles more range than the "big brands", they could bet a solid 2km range day in day out, and people managed well over that in real world testing.. ( some got to 4kms)

These were just my experiences in my own testing... I'm sure more knowledgeable people will chime in.

Hope that helps?

Thanks

dave

HarryC 06-18-2014 02:05 AM

Olnico of this forum has regularly got 6km measured range with his favourite system.
GPS on my jets shows I sometimes fly 1.6km away, data logging per second shows the Rx is still getting 95 - 100% frames/second at that distance. (Same system as Olnico)
The manufacturer claims greater than 3km range with an unobstructed view.

I think range is more dependent on the Rx than the Tx.


Originally Posted by ticketec

Using a white coloured 1.2m span slow moving model I was able to see it up to about 1.2-1.3km away, but that's only if I watched it all the way out. After about 700-800m it is almost impossible to look away and find it again in any reasonable amount of time. working out which way it's going was pretty much un-achievable either. so that's roughly how far an average person can see a model.

1.2m is a small model and is not representative of the typical jet model size.

Justflying1 06-18-2014 02:13 AM

Dave,
thats some great information. Thank you for sharing.
Thank you for not mentioning names, this is just purely out of curiosity as I have been asked every now and then but didn't want the tread to turn out into a war brand.

Justflying1 06-18-2014 02:16 AM

Since I'm guessing there will be a number of people who will reply to this tread I thank you all for the ones that put there input in.
Happy flying.

WimB 06-18-2014 03:45 AM

the brand I use ("German" but made in China) claims 4km......never tested it that far, nor will I..........I can say that up to now, not a single issue with range on any of my planes.....

Wim

gooseF22 06-18-2014 04:30 AM

When I get that question, I say " farther than I can see it" :)

GrayUK 06-18-2014 04:49 AM

Been flying 2.4 since day one, with a main brand. Never had a single range issue.


Paul G

gooseF22 06-18-2014 05:28 AM

Actually back in 2008 when 2.4 was just getting rolling, we used 2.4 to override our UAV FPV GpS based systems.. we had datalink out to several miles with the 900 and 1.5MHz systems, and would bring them within visual range, and test the link, then eventually take them over and land them.. pretty far out.. a mile or so

ticketec 06-18-2014 05:43 AM


Originally Posted by HarryC (Post 11825485)
Olnico of this forum has regularly got 6km measured range with his favourite system.
GPS on my jets shows I sometimes fly 1.6km away, data logging per second shows the Rx is still getting 95 - 100% frames/second at that distance. (Same system as Olnico)
The manufacturer claims greater than 3km range with an unobstructed view.

I think range is more dependent on the Rx than the Tx.

1.2m is a small model and is not representative of the typical jet model size.

Holly crap! you must have eye's like eagles and fly massive models!!! We had 3 different people not see it, and at that range, the model was less than 2mm wide if you held a ruler up.

My 1.2 is not exactly unrepresentative, falcon 120 is only 1.6m span... but my FPV ship wasn't travelling at 200km/h either :O
Were do you set you home on the GPS?

Goose22,

Yeah, that's why I use 900mhz for the visuals and 433mhz for a/c controls now. Guys are getting 30km with 433mhz. The lower the frequency, the better the range and the ability to get around buildings/trees etc..

HarryC 06-18-2014 06:11 AM


Originally Posted by ticketec (Post 11825547)
Holly crap! you must have eye's like eagles and fly massive models!!! We had 3 different people not see it, and at that range, the model was less than 2mm wide if you held a ruler up.

My 1.2 is not exactly unrepresentative, falcon 120 is only 1.6m span... but my FPV ship wasn't travelling at 200km/h either :O
Were do you set you home on the GPS?

Oops, my error, it was 1km, not 1.6km, but I could have seen it ok at another 0.1km. The model was a mere Trim Sabre, span 66" or just under 1.7m, metal-koted so it blends into the sky! It's small by current jet model standards.
1.2m is only 47inches, less than a typical .40 glow motor sports model, that is small by today's standards.
Not sure what you mean by "home on the GPS". I don't have any stabilisation or auto pilot systems, there is no return to home capability. The GPS logs position, speed height etc for telemetry and review later on a google earth 3D ribbon.

Rob2160 06-18-2014 06:30 AM


Originally Posted by Justflying1 (Post 11825460)
Does anyone know what would be the range of a high end brand radio. No Specific name war needs to be started and as a matter of fact I don't want any brands mentioned.

Would say 4 km be realistic before you loose contact. Obviously you will not see a plane at this distance and I sure not interested in flying anywhere close to that but I am curious and I get asked the question every now and then.

After 30+ years of flying transmitters with meter long antennas I couldn't take the 2.4Ghz radios seriously at first glance.

In 2010 I decided to try them. After reading conflicting advice on Futaba and Spektrum I decided to buy one of each, A DX6i and a Futaba 6EX and compare them myself against my trusty old Kraft radio which I knew was good to over 1000 meters range.

This testing was for my own benefit to gain confidence in the range of 2.4. I was not trying to prove one brand better than another nor determine the precise range of 2.4Ghz which is affected by many things.

I posted the results on this thread when I first joined RCU about the same time. http://www.rcuniverse.com/forum/rc-r...ml#post9829320

Unfortunately the attached photos / maps didn't survive the RCU upgrade.

But your estimate of 4km is pretty accurate for clear line of sight.. When spectators ask, that is what I usually quote.

A few more vids if you are interested. (most of these tests were done in Perth)

https://www.youtube.com/watch?v=PPIWgfgvxAU

https://www.youtube.com/watch?v=KVIR0a9s8TE

flycatch 06-18-2014 09:01 AM

Unless you fly gliders or jets what difference does it make. Line of sight is always the rule and if you most fly distance than the bigger the better. In the USA the FCC regulates the power output of transmitters and I know that it well below 1 watt.

Justflying1 06-18-2014 11:45 AM

4 km is what I have told them as that's what I have been told when asked the question. Funny enough the next thing they say is how can you see it that far LOL. Well than you have to tell them the obvious that I don't fly it out that far and keep it where my eyes can see it.

Like stated in my first post this was just out of curiosity. There is no problem with my brand radio or anything else of that matter.
Happy flying


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