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headhunter23

How to use your diversity to find your downed plane

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Well was taking the zagi out for a spin, just finished it yesterday and testing out the video link. Worked great till I went too low over a hill, anyways drove to the the general area (just a big farmers field). Looked where I last saw the video breaking up. No luck after 5 mins, used radio to rev motor a couple times, couldn't hear it. Anyways was wondering if I could use my diversity to find the plane as it beeps every time it switches antennas(just stock rubber). Vid 1 was stronger, in fact so strong that it almost always was the chosen video input by the diversity box. So stuck that out the back of my av back and the poorer antenna out the front and started waving around and using the beeps to locate. darn near led me right to it. :D

Still I would like to get the new osd from rangevideo but would have to save up so I can just punch the numbers in from the gps, but this works fine providing your battery doesn`t dissconnect during landing. ;)

Ivan.

Ps if this is wrong forum move this post... I just figured its a good tip

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Ah just came up with another way even if you don`t have a diversity, what about having a very focused antenna and just waving that around. Still the problem would be if battery disconnected from plane. I guess you could embed a backup battery just to the tx on the plane... ideas

Ivan.

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thinking more about this... I`m not the greatest on capacitor sizes, I`m sure that having a capacitor that runs down in say 30 mins would be pretty huge rightÉ (don`t ask me why but vista has replaced my question mark with a E with line on top... I hate vista) anyways have been trying to devise a way that tx will stay on for 30 min after battery disconnects without having to remember to flick a switch or turn off or on something. As eventually I would forget at some point to turn on back up system....

perhaps .... or maybe an automatic switch that arms backup upon disconnect similar to lma from rc-cam, when battery is plugged in and uses a momentary switch to turn off (perhaps with alarm so I know to flick off back up power)... still rolling around. ideas appreciated. :)

will look at lma again closer.

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Ha Ha, you realy must find your ?

I only use a small lipo velcro to my video TX, they stay together pretty good.

Terry

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I had tried fiberglassing this zagi 60 with a light layer(to avoid spar and be lighter than tape), unfortunately it became surprisingly brittle (one bad throw split the wing), but stiff, did use a 2100mah lipo which was nice and light but wanted the zagi a little tougher so taped the whole thing which added enough weight to the back that it needs a 3200mah battery on the front to balance it. The tape works but I`m not a fan of it, plus I try to avoid putting in a carbon fibre spar due to interference concerns. Planning new zagi tonight... how big is yoursÉÉéÉÉéÉÉÉ daaaaaaaaaaaamn it where is the darn question mark!!!!!!!!

I hate rebooting... i hate vista... burn in heck microsoft for making increasingly crappier products!!!!!!!!!!!!!!!! :angry2:

Edited by headhunter23

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I think you may have Vista set to the wrong country keyboard.

How big is my what ?????????? sorry got carried away with the ? just feels so good :)

I use a 600mAh lipo just for the video camera and TX on all my planes, plane sizes from a slow stick to 8ft span home design.

Terry

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Ah just came up with another way even if you don`t have a diversity, what about having a very focused antenna and just waving that around.

I managed to find my plane a couple of times with a simple 8dBi patch. Wave it and walk towards where the image looks best or the missle of the range where it's good. But,

Still the problem would be if battery disconnected from plane.

most times that's what happened.

Regarding the capacitor thing, you don't want that. A cap that can power your TX for 30 mins would be 4 times the size and weight of your flight battery, cost $300, and require a suitable DC-DC converter to get a fixed voltage out of it. But the good? point is that you could recharge it in less than 1 minute. ;)

They're just not meant for the same thing as a battery. They're very good fast energy buffers, but won't be any close from competing in such an application.

Edited by Kilrah

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I managed to find my plane a couple of times with a simple 8dBi patch. Wave it and walk towards where the image looks best or the missle of the range where it's good. But,

most times that's what happened.

Indeed. I got led bargraph displays on my reciever and it's very useful as long as the video TX still transmits, and as long as there are no other TXs on similar frequencies near. In my area, they are :( The last 2 crashes I had got the front half of the plane crushed into pieces, and nothing survived. The lipo was squezzed and I found the videoTX 5meters apart from the plane.

What you really want is a reliable beacon that stilltrasmits when everything else doesn't work anymore. It has to be "crash-proof", needs it's own battery, and has to be totally independent.

The second thing you will love is a simple Lost Model Alarm beeper for the "close range approach".

From my experience :o , I can only recommend this! ;)

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Could use a PIC driving a sonalert or similar that energizes upon signal loss. Package it up with it's own 100, 200 mah battery pack so it's crashproof.

Make a directional mic with amp & headphone to locate it from a distance.

Edited by W3FJW-Ron

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Just curious is there a little chip that shuts off power if lipo gets bellow so many volts? Yes I know the esc will do this but wondering if there's a standalone chip or whatever that would be between battery and esc or whatever draws power.

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Among R/C stuff I've seen devices that go between the receiver and ESC, and have a battery connection. When the battery is empty the devices cuts the throttle signal to stop the motor, but without cutting the battery supply itself. Wouldn't be cool to have the battery completely disconnected and thus lose R/C that was powered through the BEC...

Haven't seen one that cuts the battery, might be able to find some in other application fields...

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You can probably Google up a chip but it won't handle the current for a motor. You'll still need FETs and drivers. Best to use the type Kilrah suggested.

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You could use what I made the other day to let me check the capacity of my cells. I used it to stop the discharge when any cell got too low so I could take the capacity reading from my Astro Watt Meter but it could be used to cut the power from anything realy.

I used a standard 12F675 and a power FET but I guess you could make it in SMT if you need it small and light.

Terry

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Interesting... just was thinking about it after doing a bunch of searches on how to find your airplane otherwise. Seemed a lot of people that hadn't found their plane the first night needed to replace the lipo, so I figured even still it would be a good idea to have battery disconnect at some point. Perhaps you could have your esc shut down at a high point and a chip that cuts power right out at it's lowest safe point for lipo... just thinking is all.

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I think the best way to ensure you don't loose your plane is good preparation. If this fails then knowing where your plane is at all times, this often means flying a flight plan of some sort.

This should bring you close enough to hear a good loud lost model alarm, also a bright colour plane will help if you spot from the air.

I find 2.4ghz can be lost if the plane lands with the aerial in the dirt, range then can be as little as 100m and the beep from a good LMA is much easier to find.

If you realy want to find a plane lost in the wild then a radio beacon of some sort has to be the way to go. A lower frequency will travel best but this all adds weight so may not be the best option for the smaller aircraft.

Terry

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I think the best way to ensure you don't loose your plane is good preparation.

Guess what I did for the first time today ?

Yep I lost my plane, I saw no wind this morning and went out to make use of it, we don't get much good flying weather here.

The lipo's were charged a couple of days ago so I thought all would be well. I took off and flew the first 600mAh out of my 1200mAh battery went so I thought just one more pass across the building site and head back when it gets to 800mAh used. So at 800mAh I pointed the plane back to me but after 2 min I had made little progress, whats going on ? 1000mAh clocked up and the motor died, Ahhhh. The nose dropped and I found I was looking at fields that I didnt recognise, OMG !

I looked up to see if I could see the plane but no. I flew circles thinking I must see something I recognise soon but no again. So I just flew it down until the video cut out, I thought I had a good idea of where it was and that veiwing the video would clinch it but when I got home the video file was corrupted, dam !

So there you go, broke my own rules and payed the price.

I was a bit unlucky too as it seems the wind started blowing from the North which is very rare here, nine times out of ten it blows from the s/w and blows my plane back to me.

So maybe I too will have to find some way to find a lost plane.

Terry

Edited by Terry

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Couldn't swing ur antenna around while using the googles to walk away from where it breaks up? If you have a yagi, and the video is still broadcasting you might have a chance at finding the plane.

Ivan.

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I lost the video at 50ft so I drove to where I thought the plane landed I swung a patch around looking for a signal but found nothing. The video battery would only last about an hour so time soon ran out.

Terry

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OOOPS! Where's that %&*%@# delete button.....

Edited by W3FJW-Ron

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One thought to keep in mind is that surface winds below about 50, 60 feet are much less due to friction with the surface. It might be wise in cases like this to fly home as low as you comfortably can. Too late this time of course.

It might be practical to use a 900 mhz transmitter transmitting a tone rather than video and using a Rx with a directional antenna to track it. You will find a lot of info on DF with a Google search.

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