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Old Feb 09, 2012, 04:42 AM
Chris R
United Kingdom
Joined Dec 2009
713 Posts
No only changed rx antenna first. then tested tx antenna's once stock rx antenna was fitted.
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Old Feb 09, 2012, 12:47 PM
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Daemon's Avatar
Lakewood, Colorado
Joined Aug 2002
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Ok. So changing Rx antennas seemed to be the greater of the two improvements if you went from having full failsafes at 2km to none.. while changing Tx antenna seems to have a small effect on RSSI that still seems to be a bit hard to explain.

ian
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Old Feb 16, 2012, 06:39 AM
KISS
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Joined Oct 2009
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Measured numbers:

at 11.24V

0.14A 1.5W
0.23A 2.5W
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Old Feb 17, 2012, 12:43 AM
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Australia, NSW, Picnic Point
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Hey Sid,

Can rangelink work with the Hitec Aurora 9?
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Old Feb 17, 2012, 12:50 AM
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Lakewood, Colorado
Joined Aug 2002
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Flew my Rangelink system yesterday and today, and both days experienced fairly significant
video interference at times. If I turned to put my body between the UHF Tx antenna
and the 1.3Ghz video antenna, the noise would go away or at least be reduced.
The visible noise *looks* like packet based external interference, consistent with
a UHF control signal. It was my understanding that RL Tx was supposed to have a low
pass filter already installed. It does not appear to be sufficient.

ian
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Old Feb 17, 2012, 01:53 AM
Chinglish-funny
Joined Mar 2011
786 Posts
Quote:
Originally Posted by Teamsherman View Post
Hey Sid,

Can rangelink work with the Hitec Aurora 9?

yes, and you can use the same pnp cable 2( for your dx8)
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Old Feb 17, 2012, 02:01 AM
Look outside the Square
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Gosford, Australia
Joined Jan 2006
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Sid, how long before you have stock in again. Sorry if you have stated it earlier.

Bx
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Old Feb 17, 2012, 02:05 AM
Chinglish-funny
Joined Mar 2011
786 Posts
Quote:
Originally Posted by Daemon View Post
Flew my Rangelink system yesterday and today, and both days experienced fairly significant
video interference at times. If I turned to put my body between the UHF Tx antenna
and the 1.3Ghz video antenna, the noise would go away or at least be reduced.
The visible noise *looks* like packet based external interference, consistent with
a UHF control signal. It was my understanding that RL Tx was supposed to have a low
pass filter already installed. It does not appear to be sufficient.

ian
Inside a LPF,It will reduce the noise,Even with this, it is highly recommended to separate the A/V RX, and UHF TX antennas physically as much as possible. and try use the HPF on vrx. of course uhf system will reduce the range, use the LPF/HPF just improve this. like 1.3GHZ(vrx/vtx) with 2.4GHZ (control),it also reduce the range.

RL TX comply with all applicable FCC requirements 2-3 harmonics less than tx power -40dBm.

Sid
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Old Feb 17, 2012, 02:18 AM
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All I can say is my TLRS Tx does not produce interference like this, at same separation,
from same video Rx and antenna... even at higher power levels (1-2W).
Using Comtech based video Rx with SAW filter mod. It generally has excellent selectivity.
If the noise is from the 3rd order harmonic then HPF on video Rx won't have any effect.


ian
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Old Feb 17, 2012, 03:43 AM
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Quote:
Originally Posted by sid.huang View Post
yes, and you can use the same pnp cable 2( for your dx8)
Awesome!
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Old Feb 17, 2012, 03:48 AM
Registered User
Italy
Joined Jun 2010
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Quote:
Originally Posted by Daemon View Post
All I can say is my TLRS Tx does not produce interference like this, at same separation,
from same video Rx and antenna... even at higher power levels (1-2W).
Using Comtech based video Rx with SAW filter mod. It generally has excellent selectivity.
If the noise is from the 3rd order harmonic then HPF on video Rx won't have any effect.
ian
Are you using linear polarized antenna on Vrx?
Exact same experience here, very noisy video when RL tx is within 1-1.5 meters with LP antenna..
With Vrx on the tracker, at least 5-6 meters way from the RL TX, no problem.

With CP antennas, no problem even if RL is next to it.


Sid, any news on the Futaba 12ch PPM compatibility? Looking forward to test it, even with reduced resolution and latency for the last channels, won't be a problem.
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Old Feb 17, 2012, 05:27 AM
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Lakewood, Colorado
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Using CP antennas on both ends of video link. Have used this exact combo with TLRS without significant video noise for about a year. Have other issues with TLRS though, which is why I'm testing RL. I think RL Rx may have better input filtering thus more reliable in my high Rf environment, but what I'm seeing in the video could be a show stopper, if I can't find a filter to fix it.

ian
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Old Feb 17, 2012, 05:54 AM
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Locko's Avatar
Australia, WA
Joined Oct 2011
555 Posts
Ian, are you talking about this type of video problem:
Videoproblem (2 min 33 sec)
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Old Feb 17, 2012, 10:54 AM
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United States, TX, Brenham
Joined Jul 2011
229 Posts
You guys are running into some of the same issues I've had with 1280 Video. When I first got the RangeLink and tried to use an omni antenna sitting 3 feet from the vrx....this happened:
1280 Mhz Interference (1 min 34 sec)

(Note: this happened to be a particularly noisy RL that Sid took care of for me)

That being said, I set out on a mission to figure out how to use this. I threw the 600mhz crystek lpf from digikey on the RangeLink and that helped quite a bit. If I want to go far, I have to sit a good ways away from my directional 8dbi patch. My best results have been sitting ~25ft behind the patch and have been 4.25 miles without any trouble. The further you can get away the better it seems. I just ordered the improved SAW filter for my VRX to see if I can improve things on that end some. I have yet to try 2.4ghz video with it.

4.25 Mile flight with digikey lpf sitting 25ft behind 8dbi patch. 4 mile mark is ~2:00 so you can see there aren't problems with the video.
Bixler FPV 4.25 Mile Flight (4 min 44 sec)
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Old Feb 17, 2012, 11:03 AM
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Lakewood, Colorado
Joined Aug 2002
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Yep, both videos are representative of what I'm seeing.
I can't fly standing 25ft from my ground station, and never have had to before.
There is a way to fix this.

ian
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