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Old Oct 17, 2010, 10:53 AM
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FPV system setup philosophies by Team BlackSheep

I'm getting sick and tired of constant discussions filled with superstitious and non-factual contributions about issues that are plain and simple and not even worth a 2nd thought. There is so much misinformation being spread on the FPV section of this forum I feel the need to put all of the things that have been tried & tested in countless environments and situations by myself and other experienced FPV pilots into a nice little list. Follow these simple rules and regardless of what everyone else is saying, you will have success in FPV. This does not mean that not following this list means your FPV system will not work at all, but it does mean it will not work as safely, as reliably and as well.

Before we get to the list, let me just point out that while these points reduce the possibility of technical failures resulting in the loss of your aircraft, they do not account for stupidity on behalf of the pilot. If you want to fly into a tree and you consequently lose your plane, well, you shouldn't have flown into the tree.
  • Start with the bare essentials and add equipment one step at a time. after each new equipment was added do proper range- and stress tests.
  • Do not fly with a video system that is capable of outperforming your R/C system in terms of range
  • Do not fly with a R/C frequency higher than the video frequency (e.g. 2.4GHz R/C, 900MHz video).
  • Monitor the vitals of your plane (R/C and battery). Flying with a digital link without RSSI is dangerous.
  • Do not use 2.4GHz R/C unless you fly well within its range limits, in noise-free environments and always within LOS. since this is most likely never the case, it is recommended to not use 2.4GHz R/C systems.
  • Do not fly at the limits of video. if you see noise in your picture, turn around and buy a higher-gain antenna before going out further.
  • Shielded wires or twisted cables only. anything else picks up RF and can cause problems
  • When using powerful R/C transmitters, make sure your ground station equipment is properly shielded
  • Adding RTH to an unreliable system does not increase the chances of getting your plane back. Work on making your system reliable without RTH first, then add RTH as an additional safety measure if you must. At this point you will most likely realize RTH is not required.
  • Avoid powering the VTx directly. step-up or step-down the voltage and provide a constant level of power to your VTx, otherwise make sure your VTx runs reliably until the battery dies. Try to avoid 12V VTx on 3S systems.
  • Do not power your camera directly unless it works along the complete voltage range of your battery. step-up or step-down the voltage and provide a constant level of power to your camera. make sure your camera runs until your battery dies.
  • A single battery system is safer. 2 batteries in parallel to mitigate further sources of failure. reverse current protection is recommended, but usually not feasible
  • For maximum video range, use 2.4GHz video with high-gain antennas
  • When flying with R/C buddies that fly on 2.4GHz, or when flying in cities, it is perfectly possible to use 2.4GHz video provided you stick to the channels that do not lie in their band (ch5 & 8 for lawmate)
  • Do not use diversity as a replacement for pointing your antennas. diversity should be used to mitigate polarization issues
  • Improving the antenna gain on the receiver end is better than increasing the output power (except in RF-noisy areas). 500mW is plenty of power, more tx power causes more issues with RF on your plane.
  • Do not buy the cheapest equipment unless it is proven to work reliably (e.g. capacitors falling off, multitudes of bugfix firmware updates, community hacks and mods are a good indicator of poor quality and something you do NOT want to buy). Saving $50 is simply not worth losing your plane.

Phrases in italics are my opinion and should be taken as such - opinions can evolve over time and are subject to change. The rest is fact, don't even bother discussing it

I will respond to questions and I'm happy about suggestions to add to this list, but I will not respond to the usual "well, it depends" criticism. flame away!
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Last edited by trappy; Nov 01, 2010 at 07:24 AM.
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Old Oct 17, 2010, 11:06 AM
RC = FUN
Fort Wayne, Indiana
Joined Aug 2008
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What do you mean by step up or step down for camera and VTX? Thanks, -Tyler



BTW, great idea for a thread! This should be a sticky...
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Old Oct 17, 2010, 11:06 AM
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I think I'd have to disagree about using 2 lipos in parallel being better for redundancy. Unless you have some sort of reverse current protection between the batteries to stop them charging each other then you're just asking for trouble. If one cell of a 3s lipo fails, then you essentially have a 2s lipo being charged at 3s voltage and we've all seen the lipo fire videos of when people charge them at the wrong voltage.
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Old Oct 17, 2010, 11:11 AM
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Quote:
Originally Posted by flyboy321 View Post
What do you mean by step up or step down for camera and VTX? Thanks, -Tyler
Let's say you have a 3S battery and you run a 12V camera. the extremest voltage range supplied to the camera when the battery is connected directly is 12.6V to 8.5V (or thereabout). if your camera does not work along this range, you should add a component that works at 8V - 13V and provides a constant 12V out. for the video TX, this is even more critical as VTx usually decrease in output power (=range) with voltage.

Quote:
Originally Posted by lovegroove View Post
I think I'd have to disagree about using 2 lipos in parallel being better for redundancy. Unless you have some sort of reverse current protection between the batteries to stop them charging each other then you're just asking for trouble. If one cell of a 3s lipo fails, then you essentially have a 2s lipo being charged at 3s voltage and we've all seen the lipo fire videos of when people charge them at the wrong voltage.
doesn't work that way in practice. it is absolutely fine to fly your plane with a damaged cell, you will probably damage both batteries but there should be sufficient time to land your plane in the event that happens (you will notice, voltage drops immediately, power to your motor is reduced significantly). having said that, using redundant batteries does not exclude a reverse current protection.
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Last edited by trappy; Oct 17, 2010 at 11:24 AM.
Old Oct 17, 2010, 11:23 AM
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Hey Trappy, that really is a good list and I def agree with most of it. I think the reason people have so many disagreements is cuz everyone does things slightly different, or likes a different way of flying, etc.

What's interesting about this hobby is that two people can have identical setups, but get completely different results.
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Old Oct 17, 2010, 11:27 AM
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ashdec87, maybe. but this list was made with all that in mind. given a smart pilot, following this list to the letter will give you the best results over all the alternatives. if there was a "it depends" thing, it wasn't included in the list (e.g. "bigger batteries equal more range" or "pushers are better for FPV")
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Old Oct 17, 2010, 11:28 AM
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When something is working, that's doesn't mean it's the only way to do it !

Are we all end with exactly the same plane/setup/etc... ?? Sounds boring...

I'm flying on 2.4ghz rc link, 1.2ghz video, 2 separate battery and only with cheap chinese equipement . Each system has limitation, you just need to know it...
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Old Oct 17, 2010, 11:28 AM
RC = FUN
Fort Wayne, Indiana
Joined Aug 2008
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Wow! I never even thought about it like that. That makes a lot more sense now. Another question:

If you have a long servo extension going to the tail of the plane, is it better to put the ferrite ring closer to the servo or the receiver? Thanks! -Tyler




Quote:
Originally Posted by trappy View Post
Let's say you have a 3S battery and you run a 12V camera. the extremest voltage range supplied to the camera when the battery is connected directly is 12.6V to 8.5V (or thereabout). if your camera does not work along this range, you should add a component that works at 8V - 13V and provides a constant 12V out. for the video TX, this is even more critical as VTx usually decrease in output power (=range) with voltage.
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Old Oct 17, 2010, 11:29 AM
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CrashAndFix: I never said it's the only way to do it. I just said it's the best way to do it and there is no better way. if you want to get the maximum out of your FPV experience, this list is for you. just because you don't follow the list doesn't mean your system won't work, but it will not work in as many cases, as reliably and as safely as the ones that follow this list.

flyboy321: next to the servo (receiving end). for cameras it's the other way around (next to the camera).
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Last edited by trappy; Oct 17, 2010 at 11:37 AM.
Old Oct 17, 2010, 11:37 AM
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Useful points, particularly:

Quote:
When flying with R/C buddies that fly on 2.4GHz, or when flying in cities, it is perfectly possible to use 2.4GHz video provided you stick to the channels that do not lie in their band
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Old Oct 17, 2010, 11:57 AM
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This thread can only end in tears.
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Old Oct 17, 2010, 12:03 PM
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Quote:
Originally Posted by BushmanLA View Post
This thread can only end in tears.
Why? Because someone is bound to use a near depleted second battery for the Vtx and hasn't set a home location on his RTH enabled OSD and sees it fly away over the horizon when the OSD detects a battery low condition on the Vtx battery and engages the RTH? Although unfortunate you've got to appreciate the irony in that

Cheers,

Sander.
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Old Oct 17, 2010, 12:17 PM
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That is a near perfect distillation of success! Thanks Trappy!

I still use a video battery so the video system isn’t subject to throttle induced voltage drops (especially at the end of a flight i.e. battery capacity) and so that I have running video long after that plane has “landed”. But I have concluded that the one battery system is equally valid given a different set of design considerations so I see this one as 50%/50%. Not worth the ad nauseum “one or two” battery discussions.

Jeff
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Old Oct 17, 2010, 12:39 PM
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You forgot to mention what plane is best to use ?
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Old Oct 17, 2010, 12:46 PM
RC = FUN
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Quote:
Originally Posted by liteglow View Post
You forgot to mention what plane is best to use ?

Read...



Quote:
Originally Posted by trappy View Post
If there was a "it depends" thing, it wasn't included in the list (e.g. "bigger batteries equal more range" or "pushers are better for FPV")
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