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Old Oct 05, 2012, 08:20 PM
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guaglione87's Avatar
United States, TX, Arlington
Joined Apr 2012
687 Posts
many might recommend a futaba 72mhz transmitter, 7cap or 9cap. Then I dont know which rx to recommend. I just bought my pnp and got a spektrum rx, and am getting around a kilometer, which is probably enough for short range fpv... in any case, i would not go with the rtf setup if you want to pursue the hobby, get a programmable rx
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Old Oct 06, 2012, 05:47 AM
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Norway, Hordaland, Årstad
Joined May 2009
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Quote:
Originally Posted by Martin. View Post
In fact they are! But in the vertical plane, not the horizontal plane. It depends on what your goal is. If you want to fly in all directions, 360 degrees around, high & low then a low gain is better. But if you want to go for distance, a high gain is needed (and/or a sensitive receiver).

To understand it better, have a look here:

http://www.rcexplorer.se/Educational/gain/gain.html

The amount of 'clay' corresponds with your vtx power.
btw, even with a patch you can fly behind or aside the antenna, but not as far as in front of the patch.

Martin
----------------------

Thanks a lot for a very informative reply. To me it seems like maybe the patch antenna can be good for some flights then, if planned right.
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Old Oct 06, 2012, 08:06 AM
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Joined Mar 2012
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Will i be able to power up my fpv system, http://www.bevrc.com/mulitirotor-wir...bo-1_p461.html , with this battery: http://www.bevrc.com/t80-stock-batte...lipo_p417.html ?
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Old Oct 06, 2012, 12:14 PM
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United States, VA, Virginia Beach
Joined Aug 2005
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Just buy a UHF and be done

Today's experience reaffirmed my decision not to fly FPV with a fixed wing plane until I buy a dragon link or similar system.

One of my fellow fliers at the local flying spot came out with his FPV ship to fly under goggles for the first time. He is flying 900mhz with a 1.5Mw Tx. His radio is a Futaba 2.4.

Flying directly overhead under goggles at about 300 M he was doing great. Me and another flyer were spotting and BSing with him. The wind was picking up and he was getting blown down wind so I suggested he put the nose down and give it some throttle. He kept drifting further away and higher to the point I could hardly see it LOS. Then it happened. I watched the plane start diving straight down and the spiraling and the pilot said he lost radio link. I lost Sight of it behind the trees but he managed to recover it after regaining radio link. This happened a few times more on the way back to us each time I thought he had lost it. He managed to fly low to keep the radio link locked.

The only thing that saved him is the fact he had solid video the whole time. after landing we discussed buying a UHF system and he agreed. Crazy...
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Old Oct 06, 2012, 03:29 PM
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Mike,

Thanks for the story. I definitely don't want that to happen to me! What radio should I buy to be able to go with UHF? I'd like to order as much as possible from one place, but if HK isn't the place to get my tx/rx from that's fine. I basically need someone to say "buy this" so I don't get a piece of crap that will do what this guy's radio did to him.

Craig in PA
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Old Oct 06, 2012, 03:57 PM
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United States, VA, Virginia Beach
Joined Aug 2005
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Quote:
Originally Posted by mp43sniper View Post
Mike,

Thanks for the story. I definitely don't want that to happen to me! What radio should I buy to be able to go with UHF? I'd like to order as much as possible from one place, but if HK isn't the place to get my tx/rx from that's fine. I basically need someone to say "buy this" so I don't get a piece of crap that will do what this guy's radio did to him.

Craig in PA
I'm by no means a FPV expert but ill try. The radio in the story was a standard Futaba 2.4 but not a POS. The problem is 2.4 is intended to be LOS and nothing more. On top of that he's transmitting 900 MHz at 1.5 watts in close proximity to the radio Rx. His radio did much better then my DX6i the week before. MY Tx is only 200 Mw and I never regained control of the plane. Went for a swim to get it.

The UHF systems are basically add on's to a standard Tx. You could go with a 72 MHz system but I prefer 2.4 for standard RC so ill most likely get one of these.
http://www.dragonlinkstore.com/v2/node/1
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Old Oct 06, 2012, 04:09 PM
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ror1's Avatar
Canada, ON, Carleton Place
Joined May 2011
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or this:
http://www.rangepiloting.com/index.p...38b021f31d54d5

will work with Spektrum DX6i,DX7,DX7s,DX8 etc
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Old Oct 06, 2012, 04:36 PM
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United States, VA, Madison Heights
Joined Aug 2011
771 Posts
Look for a Module based radio like the Futaba 9C or a Hitec Aurora 9. These will allow you to keep your 2.4 LOS planes but give the option for 72MHz as well. Obviously you need the modules but this is the best option IMO. They also work with all LRS transmitters.

Price breakdown in general terms could be +/- a few dollars

Futaba 9C $150 to $200 with FM module (there are a lot of guys that like the Turnigy 9x from HK as well but it requires a firmware update as I understand and I prefer to just turn it on program my mix and go)
Spektrum or Futaba 2.4GHz module $89
Rangelink LRS $185 (you could get this later down the road if running 72Mhz)

I don't fly UHF on all my FPV planes in fact it is only on 1. 4 are on 72MHz and only my Tricopter is on 2.4GHz. I fly the 72MHz planes the most, I like 72MHz because with no OSD you have indications your control is going, because 72MHz glitches as it nears the end of the link. 2.4GHz locks out no warning. My UHF planes have OSD so I can monitor the link quality. One of my 72MHz planes has osd, the others don't but when I get glitching I know its time to climb and turn around. A lot of guys put pan servos on the camera for this reason when flying 72MHz when the pan starts twitching turn around and RTH.

The reality is most pilots don't NEED an LRS they want one.
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Last edited by MASHTON; Oct 06, 2012 at 04:42 PM.
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Old Oct 06, 2012, 06:09 PM
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Mucho thanks. I'm learning a lot and haven't spent any money on things I really can't use which is a first for me. I can't find a source for the Futaba, but if this is the right Turnigy setup:

http://www.hobbyking.com/hobbyking/s...Firmware_.html

...........then I can order it with the plane and have everything come in one shipment.

Thanks again.
Craig
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Old Oct 06, 2012, 10:29 PM
VOLTS > AMPS
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United States, MN, Buffalo
Joined Jul 2011
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So what is the range of 72mhz compared to uhf?



Also still looking around at stuff
Bixler2 x5 and skywalker 168. The skywalker can haul a ton of crap, fly for a long time, also has yaw control, but can get blown around and you have to assemble at the field, bixler 2 is cheaper smaller can't haul as much and still have to assemble the wings at the field. x5 is all ready assembled but can't haul as much.

Both the bixler and the skywalker can utilize pan and tilt and from and the skywalker has the efficiency to stay up longer. The big advantage of the x5 is its size and portability.


is this correct?
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Old Oct 06, 2012, 11:01 PM
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United States, VA, Madison Heights
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Well UHF has better range, but 95% of pilots don't fly over about 2 miles this is within reach of 72mhz. IMO it is better to learn on 72mhz then move up to UHF later. It is not a good idea to start with UHF because it gives the new user a false sense of security so they push beyond their capabilities. Gotta start at the beginning, like learning to drive in a Honda Civic vs Ferrari.
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Old Oct 07, 2012, 12:15 AM
FPV in Hawaii
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United States, HI, Kailua
Joined Feb 2012
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Alex, I picked up a cheap 13db Yagi on eBay, but it turns out to be 1150-1250 centered on 1200mhz.
What quantifiable loss do you think I'll have on 1280?
Thank you.
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Old Oct 07, 2012, 01:41 AM
KG5AWQ
guaglione87's Avatar
United States, TX, Arlington
Joined Apr 2012
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Well, I watched Andy video "Antennas 101". Very well done.

Here is an interested question - what happens to the linear polarized range when you put a windsurfer style parabola on the rc transmitter? I can figure what happens to the spread, the gain becomes higher, but does the range increase with that?

It in essence turns your omni directional antenna into a directional, but hopefully with the advantage of adding some range, in the case that you fly out of it with 2.4g.
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Old Oct 07, 2012, 01:43 AM
FPV in Hawaii
iskess's Avatar
United States, HI, Kailua
Joined Feb 2012
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Quote:
Originally Posted by MASHTON View Post
Well UHF has better range, but 95% of pilots don't fly over about 2 miles this is within reach of 72mhz. IMO it is better to learn on 72mhz then move up to UHF later. It is not a good idea to start with UHF because it gives the new user a false sense of security so they push beyond their capabilities. Gotta start at the beginning, like learning to drive in a Honda Civic vs Ferrari.
I have to respectably disagree. The only reason to hesitate buying a LRS system is if you can't afford it. The beginner has enough variables to worry about. After getting a DragonLink I never worried about my RC link again. Now I can focus my attention on my video link and all the other little issues the pop up when designing a reliable system. I almost lost my plane using 72, and I was within a mile. Yes it is possible to get 3 miles, but not reliably. I was stuck with RTH turning on and off repetitively which really made the plane fly out of control. In retrospect I should have just turned off the transmitter, but that isn't what comes to mind when you are fighting to keep your plane from getting blown out to sea.
I lengthened the Rx antenna to 1/2 wave and mounted it on the wing. I followed all the advice here, but the technology just doesn't favor 72, it's easy to get shot down someone or something. I wish I had bought the LRS right out of the box and never hassled with 72, but I'm a real cheap ass and didn't want to jump into FPV without dipping my toe in. I've learned. Just get it! You can always sell it. It's certainly a better investment than RTH which is often hard to set up reliably in all conditions.
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Old Oct 07, 2012, 10:14 AM
Engineer for Christ
IBCrazy's Avatar
Amherst, VA
Joined Jun 2006
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Quote:
Originally Posted by iskess View Post
Alex, I picked up a cheap 13db Yagi on eBay, but it turns out to be 1150-1250 centered on 1200mhz.
What quantifiable loss do you think I'll have on 1280?
Thank you.
Buy a really cheap N to SMA adapter. The cheap ones have an impedance mismatch that puts the antenna right on 1280MHz. The cheaper, the adapter, the better. Check EBAY.

-Alex
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