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Old Jun 03, 2011, 07:20 AM
Kiwi in Germany
whakahere's Avatar
Germany
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Originally Posted by Coyote64 View Post
Yeah we have seperate receivers, immersion duo and i use RC305`s

Im begining to think i`d take the db loss of the airwave units and have a much better picture tbh, but then it might not be the rx but the vtx instead
Blue angle filtered his vRX and it seems he has come out with a much better picture. He has a wiring diagram somewhere on FPVlabs. I might have to look into that myself although at this time I am pretty happy how clear the picture is looking.

How is it looking different? What diferences are you seeing? (back to work... shouldn't be on RCgroups)
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Old Jun 03, 2011, 07:21 AM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by Coyote64 View Post
Yeah we have seperate receivers, immersion duo and i use RC305`s

Im begining to think i`d take the db loss of the airwave units and have a much better picture tbh, but then it might not be the rx but the vtx instead
Maybe my eyes are in the menatime so bad, but I really think that the picture of the Foxtech/Bev/SkyRf/... (man, we finally should name thins thing) is pretty good. I do not observe graininess at only 1km out. That comes much later.

I think whakahere's aproach is the way to go. We blindly build those antennas and have to trust we did a good job. Verifying the parameters of the antenna is what's needed. Too bad that test equipement to do this propperly is so extremly expensive.

Markus
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Old Jun 03, 2011, 07:23 AM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by whakahere View Post
Blue angle filtered his vRX and it seems he has come out with a much better picture. He has a wiring diagram somewhere on FPVlabs. I might have to look into that myself although at this time I am pretty happy how clear the picture is looking.

How is it looking different? What diferences are you seeing? (back to work... shouldn't be on RCgroups)
Filtering the Rx? Hmmmm, I think most of us power the Tx with the ESC, and thus I think filtering the Tx is more important. At least that's what I did by building my own Tx.

Markus
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Old Jun 03, 2011, 08:05 AM
Engineer for Christ
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Amherst, VA
Joined Jun 2006
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Quote:
Originally Posted by markus123456 View Post
I think whakahere's aproach is the way to go. We blindly build those antennas and have to trust we did a good job. Verifying the parameters of the antenna is what's needed. Too bad that test equipement to do this propperly is so extremly expensive.

Markus
Not as expensive as you might think if you're willing to deal with a "close enough" estimate. Get a 10GHz directional coupler (4 terminal) and use it as an SWR bridge. Place a dummy load on one side and the antenna on the opposite side. At the junction terminal, use a high frequency microwave diode. Measure the voltage at this terminal. This will correspond to the difference in impeadance between your two loads.

-Alex
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Old Jun 03, 2011, 08:20 AM
Kiwi in Germany
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Germany
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Originally Posted by IBCrazy View Post
Not as expensive as you might think if you're willing to deal with a "close enough" estimate. Get a 10GHz directional coupler (4 terminal) and use it as an SWR bridge. Place a dummy load on one side and the antenna on the opposite side. At the junction terminal, use a high frequency microwave diode. Measure the voltage at this terminal. This will correspond to the difference in impeadance between your two loads.

-Alex
whoosh .... that is the sound of something going over my poor little head I hope to find the best channel to run my current gear on just to see how clear that picture really can be at range. I hope that I can go to this club this tuesday and throw my antennas at them and they can tell me. My plan at this point is to take in a 5.8ghz cloverleaf, SPW, helical and a 2.4ghz clover and spw .. that is if I find time to hack some together tonight. I am meant to be finishing these damn reports today. I just don't have the motivation. (10,000 words written and half way still)!!!
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Old Jun 03, 2011, 09:01 AM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by IBCrazy View Post
Not as expensive as you might think if you're willing to deal with a "close enough" estimate. Get a 10GHz directional coupler (4 terminal) and use it as an SWR bridge. Place a dummy load on one side and the antenna on the opposite side. At the junction terminal, use a high frequency microwave diode. Measure the voltage at this terminal. This will correspond to the difference in impeadance between your two loads.

-Alex
Alex,

It was yesterday when I browsed website of microwave equipement manufacturers for exactly this very purpose. :-)

Markus
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Old Jun 03, 2011, 11:09 AM
Flying like an Angel.
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Austria
Joined Sep 2007
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Originally Posted by whakahere View Post
Blue angle filtered his vRX and it seems he has come out with a much better picture. He has a wiring diagram somewhere on FPVlabs. I might have to look into that myself although at this time I am pretty happy how clear the picture is looking.

How is it looking different? What diferences are you seeing? (back to work... shouldn't be on RCgroups)
FPVlabs
I am not there.

Yes, i use filtering on both VRX and VTX.

On the plane because of noise of the ESC and motor.
On the ground because of noise of the BEC for the DVR and servos for the tracker.
I am a filter junkie.
but thats improves my video quality very much. No lines,.....
Very important when you fly only with 10mW at 2,4Ghz and 15-25mW @ 5,8GHz.

Measuring equipment would be cool.
There are so many factors, why our ranges are not equal.
Building the antenna is a big factor, but the flying field too.
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Old Jun 03, 2011, 11:57 AM
Kiwi in Germany
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Germany
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Originally Posted by BlueAngel2000 View Post
FPVlabs
I am not there.
So that is why I couldn't find you lol. i knew I had seen your wire diagram somewhere. It might of been on fpv-community.de ... but I don't post there cause my german writing sucks.

Oh I know I should be running with less power too. I know I am running the fine line at the moment.
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Old Jun 03, 2011, 01:57 PM
Praying for better weather
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Where is this illusive diagram, im very interested
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Old Jun 03, 2011, 02:03 PM
Flying like an Angel.
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Austria
Joined Sep 2007
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mh, don't know which one exactly.
maybe this post?
http://www.rcgroups.com/forums/showp...5&postcount=13
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Old Jun 06, 2011, 04:27 AM
Flying like an Angel.
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Austria
Joined Sep 2007
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Quote:
Originally Posted by BlueAngel2000 View Post
small quadro copter with 16mW TX:
@CH1 to safe 250m (not much more to go)
@CH8 to safe 350m (i think i could have gone further)
Okay, i did a short test yesterday with the Airwave system to compare with the SKY-RF system.

25mW AWM661TX with CL
AWM682RX with SPW

I flew 500m with my quadro copter, with much better picture than the SKY-RF system:
here is the picture at a distance of 500m:


With a foam plane i could go for sure much longer.

For comparison, i flew with foam plane with the 16mW TX 500m, instead of 350m with the quadro copter.
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Old Jun 06, 2011, 04:34 AM
Praying for better weather
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We tested the rf-sky vs the airwaved based units over the weekend.

Same plane, same antennas, same cameras. The difference was like chaulk and cheese, the Immersion ( airwave ) system won hands down, the rf-sky was that much of a let down im not going down the airwaves route and loosing the extra gain from the rf-sky.
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Old Jun 06, 2011, 04:37 AM
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Switzerland, LU, Buchrain
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Quote:
Originally Posted by BlueAngel2000 View Post
Okay, i did a short test yesterday with the Airwave system to compare with the SKY-RF system.

25mW AWM661TX with CL
AWM682RX with SPW

I flew 500m with my quadro copter, with much better picture than the SKY-RF system:
here is the picture at a distance of 500m:


With a foam plane i could go for sure much longer.

For comparison, i flew with foam plane with the 16mW TX 500m, instead of 350m with the quadro copter.
Very strange results from you guys. You motivate me to grab out my old Sky-Rf tx and do tests as with my transmitter (which uses the same chipset like the Sky-Rf) I definately get the same picture quality like you post here at 1km and beond.

Markus
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Old Jun 06, 2011, 04:45 AM
Flying like an Angel.
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Austria
Joined Sep 2007
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Markus,

i compare 25mW Airwave with 16mW SKY-RF.

The 200mW SKY-RF system gives me the same picture quality much longer beyond the 500m range.
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Old Jun 06, 2011, 05:15 AM
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Originally Posted by BlueAngel2000 View Post
Markus,

i compare 25mW Airwave with 16mW SKY-RF.

The 200mW SKY-RF system gives me the same picture quality much longer beyond the 500m range.
Ok, thanks for clarifying.

Seems like I have to bite the bullet and "waste" a transmitter of mine by mounting a 16mW module onto it and try....

Markus
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