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Jan 10, 2010, 12:19 PM
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vic20owner's Avatar
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My first FPV flight today!


Well, I've been busy assembling my first FPV plane. I have the following:

Dual output 900mhz receiver
900mhz 500mw TX
$30 ebay camera
Trimersion Headset, hacked
Parkzone Radian
3s1300 for radio and camera pan
3s1300 for video tx and camera
3s2200 for video receiver
Spectrum DX7
AR7000 receiver

Doing a range test, I found that my range was cut in half when the video was turned on. No motor noise detected in video, everything looks good. Bad thing, wind suddenly kicked up to 15 knots Decide to fly anyway!

My plan was to first fly a few circles while sitting with goggles on my forehead, and then slip them down for a few seconds at a time. Got the plane up, slipped the goggles on and IMMEDIATELY felt confused, removed them and struggled to find the plane. Wow that was not cool. This time I tried again, got the plane fairly high, heading into the wind. Slipped the goggles on and this time I quickly got my bearings and figured out here I was. I began flying slowing at half throttle and then had to turn down wind. When I did this I lost video signal! Quickly removed the goggles and located the plane (not easy, thought I lost it). Tried again... headed into the wind, put on the goggles. This time I was in control, no issues, doing some circles and looking down to see myself sitting on the ground, facing the wrong direction with my goggles on. This was one of the weirdest things I have ever experienced. Sort of like seeing yourself from the eyes of someone else.

Anyway, I made a turn and again lost video signal. I removed the goggles and could not see the plane. The problem is I have to remove my glasses to use the goggles, so when I remove the goggles I am blind!

Out of the corner of my eye I saw something diving towards the ground, and realized it was my plane, it was far down wind, and it took me about 5 attempts to recover before I finally figured out which way it was going.

When I tried to land it took me about 3 tries due to the wind.

So, I got very lucky...almost crashed, decided to quit for the day. But over all it was a successful first test.

I realized the problem was that my receiver was sitting on the ground on top of my backpack, so when I made a turn, I was between the receiver and the plane.

So, I am going to pick up a video recorder and fly normally to get my video range issue sorted out. I am sure 75% of the problem is the receiver sitting so close to the ground.







Last edited by vic20owner; Jan 10, 2010 at 12:45 PM.
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Jan 10, 2010, 12:34 PM
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trappy's Avatar
vic20: that aluminum pan & tilt mount next to the antenna is probably another reason why you're losing signal.
Jan 10, 2010, 12:35 PM
Registered User
Interesting lessons learned. You are extremely lucky. Maybe next time have a spotter?

As for range issues, if you're receiver was sitting on the ground you're definitely right. I would recommend at very least getting antenna 5ft off ground. Also for receiver get a half wave or better antenna. The 1/4 wave antenna you have on your rx and tx both result in negative dbi gains, probably cutting your range in 1/4 compared to 0dbi ideal antenna.
Jan 10, 2010, 12:38 PM
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vic20owner's Avatar
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Great thanks, yes, next time I try flying via the goggles I will have a spotter with me. Thanks for the info. I considered making that camera mount out of plastic instead. Maybe I should go ahead and do that.
Jan 10, 2010, 12:41 PM
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man2000me's Avatar
That is a lot of battery wieght... I'm sure it helped with the wind though. I had the same problem with range and moved the Vtx to the tail boom. It helped alot. I would also upgrade to a di-pole antenna for the plane.
Jan 10, 2010, 03:18 PM
Houba ! Houba !!
rcmonster99's Avatar
I bet you are never going to wear white pants again when flying FPV

I fly my radian with one battery only. My aerial sits on top of a tripod with the legs extended and I put my gear on a camping table while I am sitting on a camping chair.

definitely get a spotter for the first few flights at least until you get your bearings and assess the range of your transmitter. give the spotter some binoculars too

Any metal body close to your transmitter is going to mess up your range , so yes, as the other say I would go ahead and make another pan-tilt. shame you really put some thought on that one

Cant wait for your first report of a new great experience. enjoy the hobby
Jan 10, 2010, 03:58 PM
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vic20owner's Avatar
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rcmonster, what size pack are you flying with? I had considered using only a single 1300, and typically use about 5 minutes of motor time max when flying. I figured using a single 1300 to run both motor and video would cut that down to two minutes of motor time. I was guessing the camera and tx were using about 500mah.

Also, I am concerned that the TX would turn off if I had to run the lipo low to get back should I end up down wind.

I would love to run a single pack if it's safe to do so.
Jan 10, 2010, 04:59 PM
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man2000me's Avatar
I use the parkzone 2200 mah and I get about 10 min of motor time and forever glide time....Never really timed it. Just guessing by how many mah I have when I get back down.
Jan 10, 2010, 05:40 PM
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vic20owner's Avatar
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Hmm, not sure I see much difference in weight between a single 2200 and two 1300s. 1300s are 4 ounces and a single 2200 is 5.6 ounces, so a savings of 2.4oz. That's not much, but I may do it anyway.
Jan 10, 2010, 06:59 PM
Closed Account
Exciting stuff.

Your camera case is a solid chunk of aluminium also btw, (looks like the panasonic cx161 with 2.9mm lense)

Its typical with that configuration you have setup to loose video signal to a degree when the plane is airborne and facing you, as not only is the camera case, servos, and bracket shielding the video signal, so are your LIPOS.

A Single 2200Mah lipo for everything is what i use in a radian, on a day with no wind, flight times are close on an hour, if its windy, can be as little as 20minutes or so, i use a 12x6 prop.
Jan 10, 2010, 07:00 PM
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man2000me's Avatar
how much counter wieght did you have to put on the tail. I guess it would be up to preference. Clean video through it all or lighter setup with clean video only with the enginr off, unless you filtered the power. Once the L1D is avaible agian I will be thermaling with ease and want a lighter stup.
Jan 10, 2010, 07:09 PM
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When running off a single lipo for everything, ive always used the lipo balance lead to power the Vtx/camera.
If its a 5v camera, then i take camera power off a y-lead from the nearest servo avalable.
Ive never seen any interference in any of my video doing it like this, i do not use any ferrites or filters either.

no counter weight, i fly it as it is, cog probably a little forward, doesnt effect its thermalling ability, it still catches thermals at tree top height.
Jan 10, 2010, 07:22 PM
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man2000me's Avatar
I'm sorry Wobby that COG question was directed toward vic20owner. I was wonder how much counter wieght with the camera, transmitter and a 1300 lipo all up front. There has to be some serious counter wieght. I have to use 2 quarters and 2 pennys to counter my dx201. He might save quite a bit of weight that way to. I tried the Vtx in the canopy, the esc, lipo, motor, or what ever else I think blocks the Vtx. Having the TX in the rear will help with COG, Weight, and signal. If i were to do it agian, and I will, I will use CAt5 cable and put the TX in the rudder.
Jan 10, 2010, 07:57 PM
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thomasscherrer's Avatar
cool flight explain, we hear this alot, and we all did exactly this,
some maybe forgot, or is lying :-)
now you learned exactly what we could have told you,
but we need to feel the pain to learn, that is just the way we work. I know I do :-)

I can add a few suggestions :
always locate a transmitter as far away from a receiver as possible,
or at least so long away as you have no longer a shorter range when tx on/off,
same rule apply to a ground stadion where you also have a tx and rx close to each other.

Video receiver antennas directional types patches or yagis will improve the range alot
when pointed to the plane.

Soon you will find out the RC system is stock, and only designed for visual range
when you go a bit futher away, like where you can not see the plane with your eyes,
then you eat your range margin and will loose RC,
this is really bad since a spotter can not help you here.
many solutions for this exist, just ask arround or search the FPV forum.

also, remember to always record your flights, a video can help locating a plane,
or educate your self about things you could have done better,
or be used to entertain us :-)
Jan 10, 2010, 07:58 PM
Closed Account
Yes i see what you mean.
I see in his photo, that red lipo is pretty much where my single lipo sits.
And the front area where the green lipo is, would normally be pretty empty, except for the tiny esc.

I guess his green battery is also blocking airflow to the esc, poor little thing is probably all squashed up under that lipo, lol.

Yes putting the Vtx in the tail certainly will narrow the amount of sheilding by components.

cheers


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