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Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

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Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Old 11-01-2006, 12:57 PM
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twinturbostang
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Default Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

I'm looking to gather some information on what you guys are running as far as RC receivers, and the layout of the components on your plane. I flew FPV the other day out to about 1/4 mile away from the launch point, and started to get glitching in the RC receiver. Video was crystal clear though. Here's my current combo...

GWS E-Starter
400F brushless, 6x4 APC, TP 2S 2000 mAH

Receiver: Berg 4L

Video Tx: BW 600mW w/ standard whip antenna
Camera: KX-131

The Berg is supposed to be a very good receiver, and I have had no problems with them (I have several). However, the video transmitter is mounted probably no more than 6" away from the receiver. I'm concerned that the minimal sepparation is causing a reduced RC range. Because the E-Starter is a small park flyer, there's not a whole lot of room to move the two components any farther away than they are. The receiver antenna is mounted horizontal with it following underneath the fuselage and continuing past the tail. The video transmitter is on top of the wing, near the CG, with the antenna mounted vertically.

So what are you guys running for receivers? And how far away are they from your video transmitters? I know two of you guys (lvspark, 2thdr) are running the exact same 600mW Tx as I am. And I know you guys have been able to fly to over 1 mile away. Jett, I know you have a rather customized setup. I have an FS8 Co-pilot like you have, but that is destined for my 56" platform. I'm looking for a good solution for the typical 35"-40" parkflyer size plane. I would like to improve my setup so that I can get larger range without fear of RC glitching.

Thanks!
Brian
Old 11-01-2006, 01:10 PM
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lvspark
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

I have hitec single conversion FM rx, and futaba FM rx. No range probs with either one although futaba glitches more than my cheap hitec..

SS set-up:
Rx's are usually around CG, and I put the AVTX out on the tail boom (maybe 12-14" away from rx) with stock whip antenna. I route the rx antenna out to the tip of wing at LE and let the extra trail behind.

EZ set-up:
Rx in pod, AVTX in front of pod maybe 2" from rx with AVTX antenna pointing down.. rx antenna goes in stock location down bottom of fuse towards tail. The AVTX case is grounded and I make sure the AVTX case is between the AVTX antenna and the rc rx. Don't know if it helps, but do it as a precaution.

ShakerAp set-up:
AVTX up front with antenna pointing down, rx maybe 5-6" away with antenna wire going out to a wingtip.


1/4 mile sucks! Have you checked your rc tx's battery or range tested it without your avtx turned on? Joe bennett uses the berg I think, and seems to do pretty good??
Might be your AVTX sending out spurious RF signals????
Old 11-01-2006, 06:30 PM
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twinturbostang
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Hey Mike. Thanks for the detailed info! Yeah, I know, 1/4 mile stinks. Although that IS pretty far away. When I normally fly my planes (not FPV), I know I don't ever go that far away. That probably is out of visual range for small park flyer's. I couldn't hear the plane at all, so I knew it was out there. A full mile is just nuts!!

Anyway, there are a couple of possible sources of the glitching that I need to explore. When I say "glitching", I didn't actually "feel" any glitching in the control surfaces. Instead, I could "see" it. I have the video camera mounted on a pan servo, which allows me to pan the camera around during flight via a spare RC channel. What I saw was the camera jittering side to side a little. When you think about it, it's possible to experience a small amount of glitching in the control surfaces, and not see a reaction in the plane's attitude. But with a camera right on top of a servo, it's immediately obvious.

However, having said that, one of the possible sources of "glitching" is the ServoMax module I have installed on that servo. This is a small electronic gizmo that plugs in-line and doubles the rotation angle of the servo. So instead of only being able to pan over approx. 90 degrees (typical motion of a servo), it now goes a full 180 degrees, which is very handy for panning. Anyways, it could be that this thing is putting out RF noise, or it's also possible that it's very sensitive to pulse width changes coming from the receiver. And the fact that it doubles the motion also accenuates the apparent "glitch". So I think my next thing to try is to remove the module and see what happens. I'll go from there, depending on the outcome.
Old 11-01-2006, 07:20 PM
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lvspark
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

I didn't mean 1/4mile flying was lame, your right, it is far away for sure. What I meant was a properly working hobby grade RC control should work for a couple miles LOS no problem. I do get small bumps now an then but they are minor.
Old 11-01-2006, 11:38 PM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Yep. I understood what you meant. I definitely *should* be getting farther range without glitching. I've got several possible sources of noise that I have to explore. So I need to dig into those. I was just curious what other people were running too. If I make any headway with it, I'll let you know. BTW, I've got a couple of videos I should be able to post soon.
Old 11-03-2006, 02:34 AM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please


ORIGINAL: twinturbostang

Jett, I know you have a rather customized setup. I have an FS8 Co-pilot like you have, but that is destined for my 56" platform. I'm looking for a good solution for the typical 35"-40" parkflyer size plane. I would like to improve my setup so that I can get larger range without fear of RC glitching.

Thanks!
Brian
Funny you should mention it. I have been playing around with some much smaller and easier to deal with planes recently, and I have been using my standard JR PCM 10X transmitter with its standard antenna. I am running a 1 Watt 2.4 GHZ video transmitter and with the FMA CP8 I am getting around 1.5 miles range before I start getting into a lot of failsafes the edge of its range. The edge of range is when it starts getting into continuous failsafe holding the Transmitter in a normal flying position. I regain control by holding the transmitter vertical and high as I can.

Using a JR 770 receiver and the same JR PCM10X setup I am getting 3 miles range easy , that is not even the edge of the range but I have some work to do on that plane before I let it get to the edge of its range.

I will post some videos and pictures of the setup as soon as I get a chance.

JettPilot
Old 11-03-2006, 09:46 AM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Thanks for the info Jett. Sounds like receiver design is very important for long range operation.

Had another question... For those of you with electric planes, how are you powering your video Tx and camera? I'm currently running mine off the flight pack. I know... I know... Shouldn't do that due to possible interference issues. And that may be the case here. But let me explain the setup. I tap into the main flight pack before the speed controller and run to a DE 5V switching regulator. Then the power feeds from there to the video Tx and camera. So the hope is that the switching regulator isolates the video power from the RC system. I can try running it off a 2 cell lipo instead (which I have done in the past). Bunch of things to test though. Weather has not been great lately (very windy). So it's going to take me a while to get to the bottom of this.
Old 11-03-2006, 11:56 AM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

There is no reason to carry around two battery packs. That is a lot of weight and room, especially in an electric airplane. Sometimes intereference will be an issue, sometimes not.. It will become appearant and can be easily solved with a filtering circuit

A tantilum (10 mfd ) and electrolytic capacitor (330 MFD) in the line to your radio equipment will clean that power right up. If there is really bad RF, I would put a round Ferrite core in the power line, wrap the power wires through it.

JettPilot
Old 11-04-2006, 04:06 AM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

I always use a second smaller battery for my video equipment. Does help with interference, but I use 2 batts more for when I run the main battery down on long flights, I don't want to loose video. Call me paranoid, but some if my 12v cameras start getting freaky around the 9-10v range and sometimes I run my main li-po down more than I want to...
Old 11-04-2006, 05:29 PM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Jett,

I always use two batteries.........for the same reason lvspark said.


Rich

ORIGINAL: JettPilot

There is no reason to carry around two battery packs. That is a lot of weight and room, especially in an electric airplane. Sometimes intereference will be an issue, sometimes not.. It will become appearant and can be easily solved with a filtering circuit

A tantilum (10 mfd ) and electrolytic capacitor (330 MFD) in the line to your radio equipment will clean that power right up. If there is really bad RF, I would put a round Ferrite core in the power line, wrap the power wires through it.

JettPilot
Old 11-04-2006, 06:54 PM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

TwinTurboStang,

LVSpark and ToothDoctor have a lot more experience with Electric planes than I do, so I would go with what they recommend on the batteries. All my planes are Gas or glow powered... I use a 15 volt battery and have various switching regulators to run everything from the Video, to Radio, to the GPS. That way I only have one battery to charge and monitor But adding an electric motor to the works obviously changes things. One day I will build an electric airplane, when the cost of LIPO batteries go down so I can have enough to fly for hours like I do with gas

JettPilot
Old 11-05-2006, 12:32 AM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Thanks guys. Ok, well I will work on figuring this stuff out over the next couple of weeks. If I make any progress, I'll let you know.

In the mean time, here's a peak at one of the FPV videos I've been doing. This video was done for the Aerial Video contest over on rcgroups. The theme was "air to air". Some of you guys may have already seen the video. Anyway, a buddy and I went up and I chased him around the field. It was a lot of fun!

http://www.twinturbostang.com/rc/Air...bs_480x360.wmv 37MB
Old 11-06-2006, 02:24 PM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Wow. I tried to fly today but there was no way it was going to happen. I had SEVERE glitching in the RC system, even with the plane only 2 feet away. I turned the video system off, and it was clear out to 100' or there abouts with the RC Tx antenna collapsed. So something in the video system is causing severe interference with the RC system. This is with a Berg 7p now. I can't say for sure if the 4L was better or not. I've got to do something though.

Mike, I went back and re-read your descriptions above. What do you mean by the video transmitter case is grounded? Are you running a wire from the ground on the RC system to the video tx case?
Old 11-06-2006, 04:09 PM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

I do not have a common ground wire from my rc gear to my av gear.
The case is grounded to the power supply ground. Meaning that the transmitter case acts like a wall the rf will not pass through very well. The transmitter case is probably grounded by the nut that holds the power connector to the case, and also probably soldered in several places at the circut board level, and at the internal voltage regulators if yours has them.. You could connect you main li-po ground to your AVTX li-po ground. Probably won't make much difference since the rc Rx case is probably plastic, and I have never had to do this with avtx stuff??? Would just add to the wire mess as well.

2 different rx's and same type problem would point me to bad rx design, or avtx malfunctioning. Although, if you are using the same rc tx, that could also be the problem.

I would change out the RC gear to different brand tx and different brand rx and try that with the avtx in opperation. If you still glitch, all fingers would be pointing at the avtx as the problem.

Alternative would be if you are using the same rc tx, try a different one rc tx with the same rx and see what happens. Its either the rc tx or a bad av transmitter.. Process of elimination will eventually find the problem if you don't have proper test equipment.

Good luck!
Old 11-07-2006, 02:19 PM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Ok, I've learned a couple of things through some testing. First, my RC transmitter (Futaba 9C) appears to be working fine. I tried a buddies Hitec Eclipse 7, and it exhibited the same behavior (if not worse). Second, the proximity of the video tx (and orientation) to the RC receiver AND servo leads is very important. By moving the video tx closer to the receiver, I got worse and worse glitching. Holding it next to the receiver antenna did not result in terrible glitching. But closer and closer to the receiver itself was substantial. Also, and this was really bizarre, was when the video tx antenna was held next to or close to servo leads. The servo would actually rotate proportional to distance and orientation of the video tx with respect to the servo lead! Very strange. It must somehow be energizing the servo, or altering the signal to the servo.

So here are some things I'm going to try...

1) Move the video tx farther away from the electronics
2) Wrap the receiver body (not the antenna) in aluminum foil
3) Wrap servo leads in aluminum foil

The foil should hopefully isolate the electronics and wires from stray RF generated by the video tx. And moving the video tx farther away from everything should also help. I tried powering the video system from it's own pack, instead of through the flight pack, and that didn't seem to affect things. So I think I'm going to continue to power everything from the flight pack and monitor performance. This plane is getting so heavy now that I just don't want to add that second pack back on there.
Old 11-09-2006, 01:25 AM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Here is what I would do.... I would try these and see which works.

1. Try a different receiver. Every receiver design handles stray RF differently. Some receivers might be fine with 2.4 tx nearby while other receivers hate it and will not work. Same is true for the way that the RF gets into the servo leads. Some receivers will let it in, while others will not.

2. Try a JOMAR 8 channel OPTO ISOLATOR. That will stop RF that gets in through the servo leads, and will also solve any problems with long servo leads if you use them. I use the JOMAR opto isolator in all my planes because they have super long servo runs....

3. Move the video TX away from everything else on the plane. I already do this. If you notice in the picture below, all video equipment is on the wingtips, well away from the RC radio stuff which is in the fuselage. Everything in this plane runs off one 15 volt battery through switching regulators. See Picture below.


4. Wrap the receiver in foil could not hurt, but I doubt it will help..

RF is a biatch and seems to do different things in every case. Trail and error is needed many times to fix a particular situation. Good Luck

JettPilot
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Old 11-09-2006, 09:20 AM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

Thanks Jett. Cool, I haven't seen that plane before. I take it you like yellow.
Old 11-09-2006, 10:36 PM
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Default RE: Question about Long range FPV flying. lvspark, 2thdr, JettPilot ... help w/ glitching please

ORIGINAL: twinturbostang

Thanks Jett. Cool, I haven't seen that plane before. I take it you like yellow.
Yes, yellow stands out very well is easy to find if the plane lands in trees, grass, or even water [sm=drowning.gif] As you know, when flying miles away, its always a possibility that my plane may end up very far from me. I had to land on a dirt road 1/2 mile away yesterday [X(] My wife was flying, we lost track of time, camera fogged up from temperature changes, and next thing I know it is out of gas, and it is way downwind [:@]

Here is a picture of the bottom so that it will stand out against the sky, and I can easily tell if I am looking at top or bottom.

JettPilot
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