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qnzkrew

best way to improve video range?

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i recently made two flights which resulted in the farthest i've flown out about 1.25 miles .i have a 1000 mw tx from futurehobbies and a 14 db patch antenna from rangevideo. my video quality is mostly clear up until 1.25 miles and then it suddenly craps out :blink: . im looking for the best way to improve my range until i save money for a diversity receiver. would a ground plane antenna give me more range . i want to get max range out of my setup. thanks

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1 Watt with a 14dBi Rx antenna should give you range of > 10 miles in ideal conditions, so something doesn't make sense here.

See this post for how to do a rough calculation of range: http://www.rcgroups.com/forums/showthread.php?t=554037

One thing to remember is that the 14dBi antenna is very directional, so if you are 'dropping off the side of the beam' then the range you have seen makes sense.

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One more thing... looking at your satellite image, it looks like you flew over a forest. Remember that if there is not a direct line-of-sight path between the plane and the ground, the range will be dramatically reduced (trees are a pretty good absorber of microwave energy).

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One more thing... looking at your satellite image, it looks like you flew over a forest. Remember that if there is not a direct line-of-sight path between the plane and the ground, the range will be dramatically reduced (trees are a pretty good absorber of microwave energy).

is there a a better antenna for the tx that would improve range? i did notice that i was flying relatively low so that may have had soemthing to do with my range since i coulnt tell the position of the plane compared to the antenna on the ground . im still getting used to flying fpv and the flying site. i think iwill wait for the ORACLE so i can have a better setup.... i must say the think that i will not fly without is the inspire OSD becuase all i do is put my starting waypoint as my last and nomatter where i go the direction pointer always points me home :rolleyes:

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how are you controlling your plane ?

be aware that normal RC radios are not designed to work at ranges beyond visible contact to the plane !

More video range: use a yagi and have a helper pointing the antenna towards the plane all the time, give the helper a TV screen also, so he can uptimize the signal constantly

what happens if you loose video contact ?

you will crash and loose your plane.

Edited by ThomasScherrer

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On the opposite, I'd switch to an antenna with less gain. with 1W you wave WAY enough TX power to go very far without using that much gain. The problem is that the 14dBi antenna will indeed amplify your signal 14dB if pointed perfectly towards the plane, but as soon as you're about 30° off the best axis either vertically or horizontally (both add), you get the same as if you just had a stupid whip. A lower gain allows more veering off the straight line before the gain drops too low.

i coulnt tell the position of the plane compared to the antenna on the ground .

The above sounds like you have to work on that. The higher the gain the more you need to know where you are.

Edited by Kilrah

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how are you controlling your plane ?

i am using a jr 9303 for radio signal and i only got one hit flyign around for over 2o minutes and it was at close range .i havent had any porblems with the rc range yet. and i use my girlfriend as a spotter all times she keeps visual contact with the airplane. i have gps with imspire osd and hopefully if my plane ever went down that can help me find it . i also bought a tinytrack for realtime tracking but i am having problems making that work because iim not an expert with electronics. im waiting to see how the dzl modem your working on comes out so i can buy one... and KILRAH thanks for the tip on using a lower gain antenna with more width i will be getting one.i follow you projects faithfully. i am acutally dying to get one of those headtrackers now that i have my pandora kit from mr. rc cam but since i bought a jr 9303 i don t wanna go out and spend money on another radio that is compatible with the headtrackers. thanks for your input

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-AT-qnzkrew: I am using both DZL and TinyTrak, switchable on the plane. It depends on what Visualization software you would like to use (APRS or anything else which requires straight NMEA input), and on the behaviour of your video TX/RX equipment as well.

If you are interested in details regarding setup of the TT or DZL, feel free to contact me.

Cheers,

Hartwig

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>i am using a jr 9303

since your location is not given ??

we have to guess the frequency ??

it does matter if it is 35, 40, or 72 MHz

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i live in rhode island on 72 mhz.. like somebody noted i think i just ept goin out of my antenna path since i am using a 14 db patch from range video i am goin to use a 8 db next time and also get a little bit more altitude .

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great 72Mhz have normally a nice long range

(when all parts of the installation is perfect)

but please update your profile with the location, it really helps us,

and you might even get lucky meeting up with a local FPV friend :-)

Edited by ThomasScherrer

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yes thanks ... i updated my info with my location so if anyone is is near rhode island or in rhode island and wants to meet up to do some fpv let me know lol :ph34r: thanks for the replies

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i recently made two flights which resulted in the farthest i've flown out  about 1.25 miles .i have a 1000 mw tx from futurehobbies and a 14 db patch antenna from rangevideo. my video quality is mostly clear up until 1.25 miles and then it suddenly craps out :blink: . im  looking for the best way to improve my range until i save money for a diversity receiver. would a ground plane  antenna give me more range . i want to  get max range out of my setup. thanks

:o Hello, i am a newbee in this area of telemetry. I want to build a project in a first stage: Getting an airplane (uav with live video capability) to do fly a normal fly path (example after take off just stay around the circuit). My ideas consist on getting some kind of gps device small enough, a microprocessor to process the NMEA data an transmit mechanical out put to the servos for altitue, heading and perhaps rotation for the video camera.

Start mission

step 1:It should airborne in manual mode

step 2: stwich to auto pilot (gps and microprocessor based on pre defined waypoints)

step: In step 2 the uav should make the rest of the climb to a defined altitude and maintain a holding flight pattern over the field.

step 4: Get good live video images

step 5: make a landing procedure (End of mission)

can you put me on the right track, forums, topics etc

Thanks in advance

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i recently made two flights which resulted in the farthest i've flown out about 1.25 miles .i have a 1000 mw tx from futurehobbies and a 14 db patch antenna from rangevideo. my video quality is mostly clear up until 1.25 miles and then it suddenly craps out :blink: . im looking for the best way to improve my range until i save money for a diversity receiver. would a ground plane antenna give me more range . i want to get max range out of my setup. thanks

Hi, do you have videos of your flight? I am very interested to see the qulity and the overall flight.

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Late entry. I have found out for best video and less drop outs was to mount the TX antenna 3 DBI horizontally. This gave best results. The RX has a 15 DBI patch antenna horizontally mounted to match. This is the old camera TX and RX not as good as future hobbies. Here is a video of so called beater plane out over 2 miles with futaba 4 YF 72 MHZ radio. Very high altitude at out in distance too. TX & RX From booster vision. Patch antenna from black widow av. I tried whip antenna on RX and picks up urban RF say cordless phones. The patch screens out because focus on sky only. So here is the video. Mainly check out 2nd half of video. Not too clear of video on the you tube. :)

Edited by lvsupertech

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Oh by the way, for the best control range, I routed the RX antenna wire out behind wing, through 4 inch silicone fuel tubing as for a strain relief. toward vertical. Using a "T" pin and a piece of serevo horn and a rubber band to attach antenna wire to vertical fin. Also keep the control RX away from Video TX, or you may get servo chatter on the control surfaces. ;) PS can take picture and post.

Edited by lvsupertech

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I have found out for best video and less drop outs was to mount the TX antenna 3 DBI horizontally

I have concidered this but feel it may cause more problems than it solves. If you only have 1 dipole mounted on the aircraft then you must have 2 dead areas of transmission either front and back or to the sides. You could use a turnstyle type aerial as some have used in the past or 2 transmitters on different frequencies.

I am interested to hear more from guys that have tried horizontal polarization.

Terry

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>I am interested to hear more from guys that have tried horizontal polarization.

YES, me ! it looks like an overall video range improvement in my case,

and I then have the possibility to zero out the location of the GPS,

so I will get max sat count even with TX on,

I also place my RC-RX in a location far away from video tx and in a location

where I think the radiation will be lowest.

I am also using an LNA on the video receiver side, this gives me futher 4dB link buget gain, same as if I changed my 500mW tx to a 1.2W tx, but with out the interferrience and more current and more heat problems.

my RX antenna is a homemade improved patch:

http://www.webx.dk/rc/video-wireless/patch5.pdf

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Hi Thomas, what aerial did you use on your TX? how did you avoid the nulls at each end of the aerial ?

Terry

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I use the black stiff plastic whip that came with the TX,

you see I have pointed the antenna backwards horizontally on the plane,

so the nullings will come when flying towards and away from me,

but only when doing so at a low angle/altityde, where it does not matter for me,

since my hoppy is to fly as hi as possible, up there I never see any of the two ends of the tx antenna ! smart eh ?

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I got a Low Noise Amplifier for my setup, its the Hi IP3 2.4 GHZ 25 dB preamp from Down East Microwave. I mounted it right at the antenna, it helps a bit, but does not seem to help to much, definately not 25 dB worth :angry: Anyone had good luck with LNA 's ???

There is also one advertized to be available on Intelligent Flight's website, they say up to a 4 X range increase. Does anyone know anything about that ?

JetPilot

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Edited by JetPilot

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I have had a good improvment using one in the past when my receiver was a bit deaf (the old days) but it dose very little when used with a good modern receiver.

I think Thomas is quoting the theoretical 4x but I don't think you will see it IMO.

Terry

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