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Old Sep 18, 2014, 03:50 AM
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FPV combo not working as expected

Hopefully somebody would be able to help!

I bough the combo from RMRC after seeing how well it worked on their sample video. Plugged it all and tested it in a field with direct line of sight but after just moving no more than 100 feet away, the image in the screen is almost unusable as I have more static than image.

Tried different antenna positions with the exact same behavior so kinda lost on how to work it out. It's powered by separate 1s lipo so not expecting noise from there and even wrapped with cooper foil both the transmitter and power regulator to avoid further noise reaching either quad or Vtx antenna.

Please check my setup just, possibly doing something wrong??

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Old Sep 19, 2014, 08:26 AM
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Can I see a photo of your ground station? That is likely where the problem resides.

-Alex
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Old Sep 22, 2014, 04:28 AM
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Hi Alex, and thanks for answering.

I'll take a picture this afternoon but it's just a monitor with this:
- Receiver: FOX 0.9Ghz - 1.2Ghz -1.3Ghz Wireless AV Receiver. I have it set on channel 9 which is the only one giving me image.
- Receiver antenna: http://www.readymaderc.com/store/ind...oducts_id=3175 . The four leaves one attached to above receiver.
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Old Sep 22, 2014, 07:56 AM
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Here are the pics...



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Old Sep 22, 2014, 08:10 AM
Aalesund, Norway
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Even I can see that having a circular polarized antenna on the rx side and linear sip on the transmitter is not great. You will have a great loss in distance.
On my mini tx I have soldered a cloverleaf but that was on 5.8ghz. A clover 1.3 ghz will probably be to big for this little thing.
Have you tried a regular 1.3 ghz rubber duck antenna that came with the rx ?
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Old Sep 22, 2014, 02:03 PM
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Quote:
Originally Posted by daggad View Post
Even I can see that having a circular polarized antenna on the rx side and linear sip on the transmitter is not great. You will have a great loss in distance.
On my mini tx I have soldered a cloverleaf but that was on 5.8ghz. A clover 1.3 ghz will probably be to big for this little thing.
Have you tried a regular 1.3 ghz rubber duck antenna that came with the rx ?
I've read before that it's a 27db loss.
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Old Sep 22, 2014, 05:51 PM
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Do not mix circular and linear polarisations, it don't work. as per daggad, Put a duck, co-linear, or Yagi on the rx. Or move to 5.8GHz with Circular Pols.
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Old Sep 22, 2014, 10:53 PM
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Mixing polarizations will cost you 3db which is ~35% reduction in range. This is not your main issue, though. Are you testing inside or outside? if inside, try it outside and see how it does. Your problem might simply be multipathing.

Additionally, your antenna is too close to the screen. If you can rotate your receiver and get that antenna higher in the air it would be a huge benefit.

-Alex
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Old Sep 23, 2014, 12:31 AM
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Many thanks guys and apologies as that has been a noob question . Thought that the better antenna I could use would magnify range. I'll put one of the duck antennas I have, will try with the one that came with the receiver.

Alex, I did test it outside in a field around 500m away from any house.
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Old Sep 23, 2014, 08:47 AM
Aalesund, Norway
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One can not learn without asking questions. I have been doing FPV for some years now but in large areas I feel like a noob myself. And the day we stop learning the hobby will be boring.
And your questions can help others as well !

I think it looks good on the rx side of the setup. With a good 1.3ghz tx that would give you miles of video distance.
What regulator did you foil ?

Edit: I see it is a step up to 5v.

Hmmm..hard to say what is wrong here. Only 30-50mw power but should give more than 100feet I guess.
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Old Sep 23, 2014, 09:41 AM
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As soon as I can give it a go with another antenna I'll put the results... hopefully more than what I have. I was so pissed a month ago about this that I directly bought a 1.3Ghz transmitter rating 1500mw.... hahahaha, then I saw Alex videos and understood that was an overkill. That's another rig I need to test but for that I'll use the Armattan with the huge antenna which is a more serious bird.
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Old Sep 25, 2014, 07:22 AM
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Well... finally tested today and got to the 50 meter mark (around 150 feet) with no issues but using in the receiver the duck antenna.

If I want to improve the antenna side so what would be best? better duck antenna or moving to Yagi / patch? what's best knowing it will be attacked to a DIY googles.... so weight is important?
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Old Sep 26, 2014, 08:48 AM
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Final test done!

This afternoon went to a soccer field where I had more space to check and the further I could get with good image was 113m (around 370 feet) with nothing blocking the signal in between. Possibly could have gone a bit further but not much as image started getting bad... couldn't check anyway as that was the outter limit of the field.

Thanks guys as it was just the mixing of antennas I was using in the VRx and VTx what caused the issue.

Something else to note is that I never lost control of the 200QX during the test, not one fade or hold while last time I did the same at just 70m it went nuts. That must be the change from DX8 to DX9.
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