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Sep 13, 2014, 06:34 PM
Hobbyzone.Au's Avatar
How about if tx in placed on the ground via wireless 2.4g link vs up on a 4m pole?
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Sep 13, 2014, 10:53 PM
Registered User
Daemon's Avatar
If you mean the UHF Tx on the ground, then yes that would definitely affect
your range. Tx antenna anywhere below about knee level will be pretty bad,
due to multipathing. There's a difference between flying sitting down, versus
standing up, especially when you're far out and low. If it were up on a 4m pole,
then there should be no practical limit to how far you can fly.

Mobius is known to be a little Rf noisy, but would think only if you had it very close
to Rx or Rx antennas.
Sep 13, 2014, 11:10 PM
Hobbyzone.Au's Avatar
Tks. I 'll test that scenario next flight.

Also the 12v can seems to have noise around the 433 mhz at -78 db
The cam is 2 inches away from the uhf rx. Is that too close ??
Latest blog entry: Custom Tuned Yagi Antennas
Sep 13, 2014, 11:18 PM
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Daemon's Avatar
My guess is your 12V cam *is* the problem. They're not all bad, but there
are some *really* bad ones out there. If the cam is spewing at
-78db, what's your noise floor? -90?
Sep 14, 2014, 12:38 AM
Hobbyzone.Au's Avatar
Noise floor is -90 yes
Latest blog entry: Custom Tuned Yagi Antennas
Sep 14, 2014, 12:55 AM
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Daemon's Avatar
And yes, if the camera is the culprit, then it's way too close to the Rx.
There are some 12V cameras that are too close if they're anywhere on the aircraft.
If Rlink had a more useful micro-power range mode this would be a lot easier to
demonstrate.
Sep 14, 2014, 01:12 AM
Hobbyzone.Au's Avatar
You can see how far the cam is from the rx.

Lowest noise base us everything off.
2nd lowest is everything on with cam unplugged.
Worst noise cam plugged in.

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Latest blog entry: Custom Tuned Yagi Antennas
Sep 14, 2014, 01:19 AM
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Daemon's Avatar
Ya, the noise from that camera looks pretty brutal. I'd say that's your problem.
Sep 14, 2014, 01:40 AM
Hobbyzone.Au's Avatar
Roger that! Brutal eh? Lol
Latest blog entry: Custom Tuned Yagi Antennas
Sep 14, 2014, 11:22 AM
Hobbyzone.Au's Avatar
Quote:
Originally Posted by Daemon
Ya, the noise from that camera looks pretty brutal. I'd say that's your problem.
Just back form tinkering around for the last 2 hours..... (2 am now)

found out a crazy issue..

I know the camera is noisy at the 433 band... but i found a distance where the noise drops, approx 15 cm.. for me its useless... i will get rid of this cam.

but then i kept on testing:

as my RX is behind the Camera as prevs post has the photos. i decided to move the rx away... after moving the RX away as far as i could... 30 cm plus... guess what the noise was still blasting!

This was done with my canopy totally removed from the PLANE and unconnected to any power, i powered the 12 V cam with a 3S battery directly.


So why is 15 cm a safe distance, yet my RX when moved 30 Cm away still blasting with noise from the cam??


I realized the cable of the camera all the way to the battery was emitting noise at a very high level just like the camera itself was. which didn't make sense as the camera DOES NOT connect to the RX.... so was is my RX board is full of this noise? and at the same high level as the camera itself even though the RX is 30 cm away.


I realized after much troubleshooting.... the PAN and tilt servos which are essentially makes the mount for the CAM, is absorbing the RF noise and which then its servo leads become a ANTENNA.... and carries the noise at the same high level as the cam itself right down to the RX no matter how far u put it.... i believe u can have it 5 metres away... it will still have that level of noise.


I tested this with all types of wire... on one end of the wire the RF meter was reading ZERO noise.... (3 meters away) then i take the other end.... and hold it next to the camera.... or the servo lead... dont even need make physical contact... the Noise jumps across to the wire.... (acting like antenna) and then carries it to the other end... its a loosing battle if u had to work it out!

anyways.... thought to share my findings... there is prob a professional explanation out there but it had me

I tried torroid wraps... even had shielded cable... makes no difference ... as it will use any metal as a ANTENNA... even if u wrap in foil the length of cable... its used the foil!

The main thing that surprised me was the fact No physical contact needed... just approximate in the area... it carries it... and all along the line... its Transmitting the Noise at a constant level...
Last edited by Hobbyzone.Au; Sep 14, 2014 at 11:28 AM.
Sep 14, 2014, 12:24 PM
Registered User
Arxangel's Avatar
Hmmm... may be try using CAT7 network cable to do the wiring. It is very good at keeping noise inside the cable.
Sep 14, 2014, 08:35 PM
Registered User
Daemon's Avatar
Just out of curiosity, what specific 12V camera is it?
The one I know that spews that much noise is the KPV VSN500 (550tvl) also known as the SN777.
It will do all the things you describe. It doesn't need to be physically
connected to anything on the plane to introduce noise, and no amount of external
filtering will fix it. Use it on a mini with 2.4Ghz Rc, or throw it in the trash.
Sep 14, 2014, 09:29 PM
Hobbyzone.Au's Avatar
Its a 4g mini Cmos camera, very tiny square box like 15mm x 15mm with a 170degre wide lens, being so small! it works so well! and wide view!

note photo is for reference only... the lens here is not a wide angle one.
Latest blog entry: Custom Tuned Yagi Antennas
Sep 15, 2014, 09:50 PM
Hobbyzone.Au's Avatar
Fyi. . I just gave it 5 v of power and it seems much quieter. This camera accepts 4v to 24v.
Latest blog entry: Custom Tuned Yagi Antennas
Sep 16, 2014, 03:21 AM
Registered User
Arxangel's Avatar
Quote:
Originally Posted by Hobbyzone.Au
Fyi. . I just gave it 5 v of power and it seems much quieter. This camera accepts 4v to 24v.
I always try to power my cameras with the lowest voltage they would accept. I use a similar micro camera with a 170 degree lens, and I power it with 3.3v and it works flawlessly!!


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