dsmx interference at flite fest

[josh yoder]

I had a lot of trouble with interference this year at flite fest east. Last year I had very little trouble, I even flew in the world record flight. This year I crashed repeatedly. I was using orange recievers, but I went to the store and bought spektrum recievers. This didn't seem to help. I finally started using my old transmitter (DX6i) and one of my planes would fly with this transmitter. Did anyone else have this much trouble? I'm seriously considering switching to frsky. Is frsky really that much better than dsmx? If frsky becomes very popular, will there be just as much interference? I'd appreciate advice.

-josh

 

[BridgeInspector]

I had no issues with DSMX. I did use a DSM2 on a Simple Cub and well, that lasted 12 seconds and then I pulled a DSMX from another plane to use and had no issues.

Just make sure your antennas are pointing in clear space, away from other electronics and are at 90 degrees from each other.

 

[sconner]

I flew with a DSM2 DX7 with both OrangeRX and Spektrum receivers. No issues all weekend. My buddy lost connection with two planes using two different receivers using a new DSMX DX6 transmitter. I was literally standing and flying right next to him. I don't think there is really a rhyme or reason as to why some lose signal and others don't. Best advise I can give is what BridgeInspector did. Make sure your antennas are clear of other electronics when possible. Secondly, use full range receivers when possible.

I did ponder it a while though as I also heard more people complain of brown outs than previous years. In previous years 2.4 traffic was limited to mostly those that could fit on the flight line and a few firing up transmitters in the build tent building/testing. Now you literally have hundreds tiny whoops and quad copters flying around EVERYWHERE at ANYTIME. So I suspect it's just much more likely to get your signal stepped on.

I take to heart the line I've heard Bixler say, "Bring the friends you love, and the planes you don't" I don't bring anything to FF I would cry over. If it gets a mid-air, OK. If I get a brown-out, so be it.

sconner

 

[cvdmaverick]

I had a few brownouts on my OrangeRx dsmx receivers but once i switched to my lemonrxs I had no issues the rest of the weekend.

 

[Bricks]

First question is are your receivers binding in DSMX mode? Many receivers sold are not true DSMX but DSM2.


If one does some research the Orange receivers are OK receivers and many are not DSMX but are DSM2 which in a crowd can get stepped on but this goes for DSM2 in any receiver. That is the reason Spektrum came out with DSMX for very crowded flying conditions, at Joe Nall many of the top flyers are running Spektrum DSMX and at Nall there are many more flyers then at FF. They are not using off brand receivers as many planes they have a ton of $ invested. Running a satellite receiver can be a huge help in these conditions most brown outs come from shadowing the receiver antennas or bad ESC not putting out enough juice to power the servos and receiver.

 

[LitterBug]

I think it would be beneficial to post the exact make and model of the Transmitter and Receiver modules in use at the time rather than stating a protocol in general had issues. Pictures of the equipment and RX antenna in the craft might help too. I'm not doubting there were issues, but the more details that we have, the more likely we will be able to determine a pattern to the problem.

LB

 

[Hai-Lee]

I had a lot of trouble with interference this year at flite fest east. Last year I had very little trouble, I even flew in the world record flight. This year I crashed repeatedly. I was using orange recievers, but I went to the store and bought spektrum recievers. This didn't seem to help. I finally started using my old transmitter (DX6i) and one of my planes would fly with this transmitter. Did anyone else have this much trouble? I'm seriously considering switching to frsky. Is frsky really that much better than dsmx? If frsky becomes very popular, will there be just as much interference? I'd appreciate advice.

-josh

I just did a reply to a similar question on another thread. See: http://forum.flitetest.com/showthread.php?35965-Turnigy-TYG-iA6-signal-loss

Whilst I did not attend Flite Fest I have read quite a few posts from others describing their activities and the general environment. In the post for which I supplied the link I would ask for to consider the effect of persons using their equipment at a distance from you but considerably closer to you plane than you are. Also read the other bits and see if there was anything common to you LOS situations.

Sorry for your loss!

Have fun!

 

[josh yoder]

Okay, this is about a year later, but I've finally found the problem. It was the Hobby King esc.
I bought a blheli ESC at the store tent and it fixed the problem. I have switched to Frsky, but was still having interference with the same plane.

 

[sprzout]

Okay, this is about a year later, but I've finally found the problem. It was the Hobby King esc.
I bought a blheli ESC at the store tent and it fixed the problem. I have switched to Frsky, but was still having interference with the same plane.

Funny you should mention that - I found a problem with a plane where I lost signal. Guys at the field immediately pointed to the Orange receiver, but on diagnosis at home, I discovered a loose XT60 plug. If I wiggled it, it would cut in and out - exactly like what I was experiencing in flight. Cut off the old XT60 connector, soldered a new one on, better fit, no loss of power when wiggling it!

 

[JimCR120]

Another theory was regarding yonder pump in the field potentially having some transmitter. I dunno for sure. Somebody with a directional antenna and a spectrum analyzer might be able to discern better.

 

[Liam B]

I had a few failsafes on FrSky today. Both on my quads.

 

[rockyboy]

I discovered a loose XT60 plug. If I wiggled it, it would cut in and out - exactly like what I was experiencing in flight. Cut off the old XT60 connector, soldered a new one on, better fit, no loss of power when wiggling it!

On the XT60 plugs if you look at the metal contacts on the male plug (right side in this image) you'll notice they look like four fingers or pie slices in a circle.

If the plug is too loose, just very gently and slightly spread out the four fingers and try it again. If a plug is just so tight it drives you crazy and are almost tear your plane apart trying to unplug the battery, use needle nose pliers to gently push the fingers closer together and you can get a smooth fit.

 

[sprzout]

On the XT60 plugs if you look at the metal contacts on the male plug (right side in this image) you'll notice they look like four fingers or pie slices in a circle.

If the plug is too loose, just very gently and slightly spread out the four fingers and try it again. If a plug is just so tight it drives you crazy and are almost tear your plane apart trying to unplug the battery, use needle nose pliers to gently push the fingers closer together and you can get a smooth fit.

Good idea, but there was also cracked plastic around one side. I just cut it off an re-soldered on a new one. Probably for the best; the solder joins for the connector weren't the best, either.

 

[Hai-Lee]

True radio interference is extremely rare due to the current spread spectrum technologies used. Unlike the earlier bands, where frequency management was required, the current systems actually time share the radio frequencies and are continually changing frequencies pseudo randomly to ensure that it is extremely unlikely that two radio systems will have the same order of frequency usage.

Add to this the simple fact that each radio transmission is coded digitally with a unique code and the chance of the radio interference of old is ZERO. So why do we still get random losses of signal?

Areas of potential LOS are signal blocking, and deliberate DOS attacks! Assuming that deliberate DOS attacks are going to be extremely rare in a rural location that only leaves signal blocking!

Blocking is where an unwanted signal is being received on the exact same frequency at exactly the same time and the unwanted signal is orders of magnitude greater in strength than the actually wanted signal. With the continual changing of frequencies this will only be of serious concern where there are an extreme number of transmissions occurring. Please note that for blocking to actually occur there must be a magnitude difference in signal levels.

At an event such as FF I would assume that the flight area would be a reserved area separate from where people are likely to be setting up and testing non-flying aircraft and that the flight line would be in a location such that those flying aircraft are always closer to the airborne craft than those not directly involved.

With such a simple strategy implemented it must be assumed that the vast majority of LOS incidents must have a cause outside of the actual radio spectrum and it number of competing users. So what sort of reasons could be assigned to a LOS event. Simply the radio equipment used and the installation of the gear itself. Anyone using a radio system with a single antenna Rx is almost guaranteed to have a LOS event almost every flight! This is due to the usual polarization issues inherent in a single antenna radio system.

Now here is where we look at setup and equipment. When doing a range test do you repeat the test for each antenna? I have seen Rxs which have had one antenna disconnected or even Rxs that one antenna does not work due to internal Rx fault. These Rxs can and do cause a multitude of LOS signal events.

Also are your antennas installed free and clear of all wiring and metal structures on your craft or are they just located wherever they fit or happen to fall when the Rx was installed? The number of poor antenna installations is terrifying and those responsible blame interference for their woes!

What re-association time does your radio have and does your flight controller refuse to reinitialize after a LOS unless the aircraft is in level flight? Some radios just take far too long to re-associate and you will normally find the Rx working quite well after the impact!

Having said all of the above there are infrequent cases of genuine LOS events but the vast majority of LOS events have a definite and avoidable cause that is not related to interference!

Just my thoughts on the matter!

Have fun!

 

[Bricks]

Very nice right up HL and being many of these LOS failures are newer people to the hobby and not understanding how to install and set up the receiver to work properly. For my cheap FT planes I am as guilty as the next just throw the receiver in and go, now when it comes to my balsa birds set up is done more properly.

 

[makattack]

Just catching up on forum posts while winding down my evening from a full FliteFest schedule. I was chatting with @PsyBorg after a buddy box flight with my primary trainer plane and his friend Tom who's also a FliteCrew volunteer along with Bill. Tom is newish to the hobby and totally jumping in head first. Much like I did when I started. I really felt like Tom and my experience matches. When I started, I learned about FliteTest late and it coincided with the inaugural FliteFest event. After finally having some success in RC thanks to FliteTest instructional videos and easy build kits/plans, I just knew I had to attend. I was still uncomfortable with my skills, especially in airspace with more than one plane up, so I ended up volunteering more than flying. Well, that habit actually hasn't changed from 2014, but to get back to the point of this rambling note:

While I was buddy boxing with Tom, I became inattentive to how long we had been up in the air. At one point, I allowed the plane to get too low, and while I took back control, it seemed I just didn't have enough power to climb out and the plane landed fairly gently in the bean field. The only damage was the lost prop which was on a prop saver. One of two things immediately came to mind: I lost connection, and the receiver went to failsafe which would be to cut the throttle. I wasn't monitoring my battery, and it got too low.

While speculating this with Bill, he mentioned that he observed a lot of the outages/failsafes seems to occur on either Spektrum or FrSky equipped aircraft when the oil well pump at the West end of Furey field is running. He mentioned that he's aware of a wireless telemetry system on these pumps based on WiFi, which can run on 2.4GHz.

I think that this, coupled with the WiFi network setup for "FliteTest Info" which is a dedicated onsite network to allow people to view build videos without using their mobile data plan, as well as the FT Store and Registration WiFi and whatever other mobile WiFi access points people setup at their campsites and that neighbors in the area have all combines to make even the remote FliteFest location a fairly noisy environment for 2.4GHz.

At any rate, we were speculating on all this, but ultimately, when I returned to my gear, I put a voltage checker on the battery's balance lead and quickly identified the culprit to the "early" landing in my case was a 3S battery that was pushed down to about 10.0V

Here's some information on what oil wells have for wireless networks: https://new.abb.com/network-managem...tworks/solutions/oil-gas-field-communications

 

[Hai-Lee]

A poorly setup and fully subscribed/utilised AccessPoint could be a bit of a problem but I would have thought that a sector antenna system setup so that the AP Transmissions were directed away from the flying area would be part of the FliteFest Kit. With the antenna gain the client transmission powers would be reduced power under instruction from the AP or WLC.

As for oil gas field communications it is a low bandwidth device and so whilst it may transmit often its transmissions are brief and unlikely to cause a LOS event which could extend beyond the lost packet tolerance on modern RC equipment.

My rule on batteries is to use a timer AND NEVER fly without a battery monitor/alarm.

Have fun!