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Old Jun 23, 2009, 11:47 PM
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USA, TX, Plano
Joined May 2009
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newbie need help

I did some search and found out that most people will get about 3 miles with 900mhz video . The best I can manage is 600 meter. I check and recheck and I can not find out why my video range is so short( in rural area , no interference). Please help me find out what wrong with my set up

easy star upgraded with turnigy brushless motor hxt 2835
turnigy plush esc 40 amp
spektrum dx7 radio AR9000 receiver with 2 external ant
900Mhz 500mW VTx and receiver from range video
8Dbi patch ant for video receiver
3 DBi rubber duck ant for VTx
pan and tilt for KX 191 camera
2 separate 3s lipo for video and motor

My Spektrum RC link is very solid all the time and 600 meter for video link is the best I get so far with my friend pointing the patch ant directly at the plane. My ESC and VTx is very very close together, could the esc interfence with the VTx ? Please help
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Old Jun 23, 2009, 11:59 PM
reznikvova's Avatar
Miami
Joined Dec 2001
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Which antenna are you using on the transmitter? How do you position it?
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Old Jun 24, 2009, 12:03 AM
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Joined May 2009
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Quote:
Originally Posted by reznikvova
Which antenna are you using on the transmitter? How do you position it?

I have 3dBi rubber duck ant on VTx and it point up directly to the sky
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Old Jun 24, 2009, 12:08 AM
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Quote:
Originally Posted by mwhiteknight
I did some search and found out that most people will get about 3 miles with 900mhz video . The best I can manage is 600 meter. I check and recheck and I can not find out why my video range is so short( in rural area , no interference). Please help me find out what wrong with my set up

easy star upgraded with turnigy brushless motor hxt 2835
turnigy plush esc 40 amp
spektrum dx7 radio AR9000 receiver with 2 external ant
900Mhz 500mW VTx and receiver from range video
8Dbi patch ant for video receiver
3 DBi rubber duck ant for VTx
pan and tilt for KX 191 camera

My Spektrum RC link is very solid all the time and 600 meter for video link is the best I get so far with my friend pointing the patch ant directly at the plane. My ESC and VTx is very very close together, could the esc interfence with the VTx ? Please help
what are you powering the VTX with?
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Old Jun 24, 2009, 12:16 AM
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Quote:
Originally Posted by gundamnitpete
what are you powering the VTX with?
i have a separate 3s 1200mah lipo for VTx and camera, 2200mah 3s lipo for motor
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Old Jun 24, 2009, 12:20 AM
Team White Llama!
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try rotateing your patch 90 degrees. when i build my first GP patch, i thought it didn't work worth a damn.

turns out i just needed to turn it 90 degree's to get relieable video
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Old Jun 24, 2009, 12:25 AM
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Quote:
Originally Posted by gundamnitpete
try rotateing your patch 90 degrees. when i build my first GP patch, i thought it didn't work worth a damn.

turns out i just needed to turn it 90 degree's to get relieable video
I have tried put the 8dBi patch on the ground, on top of my car, pointing directly to the sky, point it at the plane or away from it. So far I only get the best reception by having the patch facing directly at the plane. May be my VTx is defective ?
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Old Jun 24, 2009, 12:38 AM
my karma ranover my dogma
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Edmonton,Canada Eh
Joined Jun 2007
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Does the vid Tx get hot?

Make sure the center pin on the 3dbi antenna is long enough to make good contact with the connector on the Tx.
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Old Jun 24, 2009, 12:49 AM
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Quote:
Originally Posted by galaxiex
Does the vid Tx get hot?

Make sure the center pin on the 3dbi antenna is long enough to make good contact with the connector on the Tx.

the VTx indeed get very hot. I found out that if I keep my lipo voltage between 11.2v to 11.9v , the VTx is still heat up but not very hot. So I always charge my lipo to 11.9v before take off. And I think at this voltage , it is still enough juice for the VTx to function. About the center pin on the ant, I try to screw on the ant as tight as I can but I am not sure if the center pin is connected or not. How could I find that out ?
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Old Jun 24, 2009, 10:30 AM
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Joined May 2009
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I look at my VRx and it is a dual out put from range video. It has button for channel 1, 2, 3, and 4 and right next to it is a turn screw label from 0 to 9. What is this turn screw do. Do I need to mess with it ? Right now it is point at 0 .
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Old Jun 24, 2009, 11:54 AM
reznikvova's Avatar
Miami
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You should use the small dipole antenna which comes with the transmitter. Please try it.
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Old Jun 24, 2009, 01:05 PM
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Quote:
Originally Posted by reznikvova
You should use the small dipole antenna which comes with the transmitter. Please try it.
Ok I will try it that way . Also last night I mount the VTx sideway on my plane and point the ant directly to the ground. This is an effort to get away from the ESC . With this my video reception is a little bit better. I can get a little bit further away from take off point but still may be 700 meter away. I want to get longer distance than this.
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Old Jun 24, 2009, 11:23 PM
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Quote:
Originally Posted by reznikvova
You should use the small dipole antenna which comes with the transmitter. Please try it.
I did try the small whip ant on the VTx today and it is clear working better . So the rubber ant I got is defective. However my range is improve a little bit but not much. Is that the normal range for the stock whip ant ? Do I need to order another rubber duck ant to get longer range ?
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Old Jun 25, 2009, 04:00 AM
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Joined May 2007
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Quote:
Originally Posted by mwhiteknight
I have tried put the 8dBi patch on the ground, on top of my car, pointing directly to the sky, point it at the plane or away from it. So far I only get the best reception by having the patch facing directly at the plane. May be my VTx is defective ?
You still havn't done as gundamnitpete suggested ! ?
ROTATE your patch 90deg. not point it in a different direction, thats not what he meant.


Otherwize, ditch the patch for now if rotating it doesn't make an improvement.
Use a rubber duckie on your Video Reciever, and point it to the sky perfectly vertical, same on the plane.

good luck, but carefull with the Spektrum, ordinarily your spectrum rc link will go off air way before the 900Mhz 500mw video hits its range limit on stock antenaes, lol.

BTW, ive never had issues with the Turnigy plush esc's being close to the VTx.

Oh, and try sitting your Video reciever on the ground in front of you.
I always get better results with the VRx on the ground, and worse results when ive used tripods etc to get the antenaes up high.

Dont use any extension leads on your antenaes either. !


cheers
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Old Jun 26, 2009, 12:44 PM
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[QUOTE=Wobby]You still havn't done as gundamnitpete suggested ! ?
ROTATE your patch 90deg. not point it in a different direction, thats not what he meant.


I not quite follow you , right now I have the patch ant pointing in a gerenal direction that I will fly to. So to rotate the patch 90 degree, is that mean point the patch to the sky or rotate 90 degree away from the plane ?

Otherwize, ditch the patch for now if rotating it doesn't make an improvement.
Use a rubber duckie on your Video Reciever, and point it to the sky perfectly vertical, same on the plane.

I tried that and the patch does improve the signal so I will keep using it for now.


Yesterday I flow at a difference location and wow the signal was a lot better I can get really out of line of sight and still had video. However I stayed inside my flying box and did not venture out any further. I wait until I get the Dragon OSD with RTH installed before I take any risk to fly long distance.

So I guess the location I flew before has some thing inference with my video. I saw a cell phone tower near by, could that giving me problem. So bad, this is a popular location where all my local rc flyer play.
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