Flite Fest 2016 World Record

[bitogre]

DSM2 and even some genuine DSMX Receivers had problems. I had a horrible link with a 4ch Spectrum receiver, but when I swapped it for a 6ch, everything was crisp (Also, the pigtails were worn out…). I saw some people running Orange, saying they had no problems, not sure if they had tried to fly at the event yet.

I can believe that DSM2 and DSMX had problems. I forgot to log for the entire attempt on my Taranis (with X6R receiver). I turned on logging shortly after the start of the official time, after I got an RSSI Critical warning. From the point I started logging to my crash, I was getting RSSI levels as low as 52 (warning indicating questionable link are for RSSI below 45). So, assuming my RSSI levels were typical, I think we were pushing the limits of the technology (no matter which protocol your TX was using). I suspect we can do better than 179, but not by much without more improvements to control technology (maybe 200 is the limit).

I'd be curious to know if anyone has RSSI telemetry logs for the entire attempt to see how they compare to my short period of logging and see if my low RSSI levels were an anomaly or seen by others.

 

[Mostly Harmless]

A HUGE thanks to DharanFlyer for organizing this event! I was thrilled to be part of it, and even more thrilled to have been one of the 179 who successfully flew the 1 minute (and safely landed just a few yards away).

I'm sorry to say that in my excitement, I forgot to turn on my wing-mounted camera, so I have no video of the event -- I was just so thrilled to get a receiver lock (an FrSky Taranis), that I lost track of everything else. However, going through several of the videos posted on YouTube, I was able to spot my plane several times, so I have those memories.

Well done, everyone!

 

[Mid7night]

I can believe that DSM2 and DSMX had problems. I forgot to log for the entire attempt on my Taranis (with X6R receiver). I turned on logging shortly after the start of the official time, after I got an RSSI Critical warning. From the point I started logging to my crash, I was getting RSSI levels as low as 52 (warning indicating questionable link are for RSSI below 45). So, assuming my RSSI levels were typical, I think we were pushing the limits of the technology (no matter which protocol your TX was using). I suspect we can do better than 179, but not by much without more improvements to control technology (maybe 200 is the limit).

I'd be curious to know if anyone has RSSI telemetry logs for the entire attempt to see how they compare to my short period of logging and see if my low RSSI levels were an anomaly or seen by others.

I had a very different experience, however I also was using an X8R with PCB antennas (not the whisker ones). FrSky claims they provide an additional 20% range increase (or 20% stronger signal, if you like) over the standard antennas. I think your experience with the X6R compared to mine on the X8R tends to validate this.

I DID happen to log the whole flight, and it is quite interesting, in the nerdiest of ways. I also had an airspeed-sensor on board, and coupled with my wife's ground-video (where you can hear the announcer), I was able to graph RSSI and KIAS, and label the different portions of the flight.

During the pre-launch phase RSSI levels are normal; ~84dB. When Flight-4 launches there's nothing really dramatic, but there is a slight down-trend when Flight-3 launches; ~80dB. As F2 and F1 go up the downward trend increases; ~75dB after F2, ~70dB after F1. It stays right around that level during the "Official Minute", ~73dB. Inversely, you can see the levels come back up slightly as the flights land when the minute is over.

Science FTW!

 

[Dave.E]

... And we should've used more of the runway. There was still some space to the right.

I was all the way to the left and there was a lot of space for pilots. From looking at videos I think there was a lot of bunching of pilots in the middle. Maybe next attempt set number markers showing were folks should move to, might prevent some mid-airs.

 

[bitogre]

I had a very different experience, however I also was using an X8R with PCB antennas (not the whisker ones). FrSky claims they provide an additional 20% range increase (or 20% stronger signal, if you like) over the standard antennas. I think your experience with the X6R compared to mine on the X8R tends to validate this.

I DID happen to log the whole flight, and it is quite interesting, in the nerdiest of ways. I also had an airspeed-sensor on board, and coupled with my wife's ground-video (where you can hear the announcer), I was able to graph RSSI and KIAS, and label the different portions of the flight.

During the pre-launch phase RSSI levels are normal; ~84dB. When Flight-4 launches there's nothing really dramatic, but there is a slight down-trend when Flight-3 launches; ~80dB. As F2 and F1 go up the downward trend increases; ~75dB after F2, ~70dB after F1. It stays right around that level during the "Official Minute", ~73dB. Inversely, you can see the levels come back up slightly as the flights land when the minute is over.

Science FTW!

View attachment 72434

Very cool. Though you did get some spikes down below 60 and one looks like it got down to 50. But, given your graph, it looks like you had plenty of RF signal and not that likely of seeing a lockout or worse.

I too was using the PCB antennas and I doubt the X8R is much better than the X6R in terms of RF performance. I wonder if the difference is due to where you were flying and/or how you have your antennas mounted in your plane.

I guess, bottom line is more data is needed to figure out how close to the technical limit we were.

 

[Mid7night]

Very cool. Though you did get some spikes down below 60 and one looks like it got down to 50. But, given your graph, it looks like you had plenty of RF signal and not that likely of seeing a lockout or worse.

I too was using the PCB antennas and I doubt the X8R is much better than the X6R in terms of RF performance. I wonder if the difference is due to where you were flying and/or how you have your antennas mounted in your plane.

I guess, bottom line is more data is needed to figure out how close to the technical limit we were.

Oh interesting! I know you can swap the PCB antennas onto other Rx's, but the X6R by default comes with whisker antennas. I would agree there shouldn't be much difference with the internals between the X6R and X8R. Placement is definitely a big factor.

Yes, there were some spikes down below 60, but given how short-lived they were I took them to be mostly outliers in the data. The bulk of the noise-band hovered around 65-80, even after everyone was up. More data from other planes would definitely help us learn more.

 

[DharanFlyer]

I had a very different experience, however I also was using an X8R with PCB antennas (not the whisker ones). FrSky claims they provide an additional 20% range increase (or 20% stronger signal, if you like) over the standard antennas. I think your experience with the X6R compared to mine on the X8R tends to validate this.

I DID happen to log the whole flight, and it is quite interesting, in the nerdiest of ways. I also had an airspeed-sensor on board, and coupled with my wife's ground-video (where you can hear the announcer), I was able to graph RSSI and KIAS, and label the different portions of the flight.

During the pre-launch phase RSSI levels are normal; ~84dB. When Flight-4 launches there's nothing really dramatic, but there is a slight down-trend when Flight-3 launches; ~80dB. As F2 and F1 go up the downward trend increases; ~75dB after F2, ~70dB after F1. It stays right around that level during the "Official Minute", ~73dB. Inversely, you can see the levels come back up slightly as the flights land when the minute is over.

Science FTW!

View attachment 72434

That is really neat!

 

[HilldaFlyer]

I like the analysis a lot too!

I would like to learn how Spektrum DSMX, Futaba FASST and FrSky ACCST work together or against each other when doing an event like this.

 

[Knight Owl]

I like the analysis a lot too!

I would like to learn how Spektrum DSMX, Futaba FASST and FrSky ACCST work together or against each other when doing an event like this.

Me too! I would really like to see a good technical explanation of how the different protocols can interfere with each other. Is it just a simple matter of flooding the airwaves with too much 2.4 GHz? Though the coding is different between them, I assume the fundamental carrier signals can still weaken each other as they collide in varying phases, or just cause "noise"?
Mid7night -- Thanks for sharing that graph! Very interesting.

 

[earthsciteach]

I like the analysis a lot too!

I would like to learn how Spektrum DSMX, Futaba FASST and FrSky ACCST work together or against each other when doing an event like this.

Hijacking the thread here! Thanks for the pancakes, HildaFlyer!!!!! It was great meeting you at FTFF.

 

[rockyboy]

Me too! I would really like to see a good technical explanation of how the different protocols can interfere with each other. Is it just a simple matter of flooding the airwaves with too much 2.4 GHz? Though the coding is different between them, I assume the fundamental carrier signals can still weaken each other as they collide in varying phases, or just cause "noise"?
Mid7night -- Thanks for sharing that graph! Very interesting.

RC Model Reviews has a series of pretty good technical articles that go over many of the flavors of 2.4 frequency hopping (but circa 2008 - doesn't address some of the newer protocols).

http://www.rcmodelreviews.com/spreadspectrum01.shtml

He did an updated video in 2011 that covers a few more modern systems

 

[Battershell]

World Record Certificate????

Will you notify everyone when the record is verified? My daughter and I are just anxious to get our hands on the certificate for being part of the 179. Not sure how you will get a hold of everyone.

 

[DharanFlyer]

I was planninh on asking FT to make an announcement in addition to updating the thread. Lifes been a little hectic so not quite done with submitting yet. Plan to have it done by next week.

 

[makattack]

DharanFlyer/Michael, thanks for all the work you've put into this!

While you, your brother, and assistants were wrapping up the registration of pilots, I noticed a fellow volunteer who was walking around with an RFExplorer... I meant to look for him afterwards to see if he saw anything useful / had logged the event, but I didn't see him again. He was a fellow amateur radio enthusiast (ham) and had unfortunately cut his hand in the build tent trying to catch a falling knife.

Anyway, I've always thought it would be supremely useful of have an rfexplorer, but the limited functionality for the cost (which I know is ridiculous for me to say given this kit was amazing 10 or less yrs ago) has always kept me from pulling the trigger.

Now, there is an affordable SDR that is peaking my interest, and I'm probably going to save my pennies for this: https://greatscottgadgets.com/hackrf/

Anyway, thought people might find it interesting since so much of this effort also involved the RF side of the hobby.

 

[DharanFlyer]

Patrick right? Or was it Andrew... I can't remember so many names that weekend. I got to hang out with him some Friday night and he was showing me the RFExplorer. Really cool stuff.

 

[flytivoer]

World Record

I was planninh on asking FT to make an announcement in addition to updating the thread. Lifes been a little hectic so not quite done with submitting yet. Plan to have it done by next week.

Just wanted to follow-up and see if there were any updates on the submission.

 

[DharanFlyer]

Just wanted to follow-up and see if there were any updates on the submission.

Sure thing.

I have everything uploading to GWR. Took longer than I thought to get to that (personal time conflicts). I am waiting on a response from them as some of the paperwork had a wrong number listed on it as we misunderstood the question. Waiting to see what we need to do to correct it properly. I have a handful of calls to make today to people to correct some info on the pilot list.

Got the last document I needed from FT last week which got uploaded Tuesday.

 

[SP0NZ]

Sure thing.

I have everything uploading to GWR. Took longer than I thought to get to that (personal time conflicts). I am waiting on a response from them as some of the paperwork had a wrong number listed on it as we misunderstood the question. Waiting to see what we need to do to correct it properly. I have a handful of calls to make today to people to correct some info on the pilot list.

Got the last document I needed from FT last week which got uploaded Tuesday.

Do you know how long the verification process normally takes once they have everything?

 

[DharanFlyer]

They list as 1 - 12 weeks, but with FT covering the expedition cost that may affect the time to our benefit on the backside.

 

[Balu]

Hey DharanFlyer,

do you have any updates on this? It's been a while .