[Canberrauav] radio test results

Matthew Ridley mridley at velocitynet.com.au
Sun Dec 4 21:10:45 EST 2011


Great results!

Plenty of cloverleaf available here:

http://videoaerialsystems.com/products/

There is a video on youtube that shows you how to make one.

Search for ibcrazy and cloverleaf.

My 900Mhz Helical is half made, Just need to mount the helical now.

Matt

On Sun, 2011-12-04 at 20:28 +1100, Andrew Tridgell wrote:
> We got some great results testing Johns cloverleaf antennas today!
> 
> What we tested was:
> 
>  - ubiquity 5.8GHz bullet radios
>  - 20dBi patch antenna at RedHill
>  - 2 cloverleaf and 2 'rubber duck' omni antennas at Mt Ainslie
>  - tested the cloverleaf with and without Amitays amplifier
> 
> The range of the test is approximately 8km, which is more than enough
> for the OBC competition.
> 
> All of the tests were performed with the same setup at RedHill. Jack
> kept the 20dBi patch antenna pointed at Mt Ainslie. Both radios were set
> to minimum bandwidth (a bit over 1MBit) for maximum range.
> 
>   http://photos.tridgell.net/v/CanberraUAV/RadioTesting/IMG_20111204_180302.jpg.html
> 
> At the Mt Ainslie end, John, Brett and Tony operated the other radio and
> swapped between plane antennas. They had the Axis IP camera attached to
> the radio so Jack and I were able to watch a video stream from the
> camera at the other end of the link. The video test allowed us to judge
> the quality of the network link quite well.
> 
> We monitored the signal strength at each end using a script talking to
> the SNMP server on each radio.
> 
> For the tests with the amplifier enabled, we configured the radio at Mt
> Ainslie to assume 20dB TX gain from the amplifier, plus 1dB of cable
> loss. We assumed the cloverleaf antennas had a notional gain of
> 3dB. Thus the radio was configured to transmit at 14dBm, keeping the
> EIRP at 36dBm (ie. 4W).
> 
> ---------------------------
> test1: 4 element cloverleaf
> 
> amplifier was enabled at Mt Ainslie
> 
> antenna in 'normal orientation':
>    - sig level at Mt Ainslie: -82 to -84dB
>    - sig level at Red Hill:   -79dB
>    - good video quality
> 
> antenna at 90 degrees roll:
>    - lost approx 2dB of signal
> 
> antenna at 45 degrees roll:
>    - lost approx 3dB of signal
> 
> antenna pointing directly away from RedHill
>    - lost approx 8dB of signal, link became unstable, very poor video
> 
> 
> ---------------------------
> test2: 3 element cloverleaf
> 
> amplifier was enabled at Mt Ainslie
> 
> antenna in 'normal orientation':
>    - sig level at Mt Ainslie: -83dB
>    - sig level at Red Hill:   -81dB
>    - good video quality
> 
> antenna at 90 degrees roll:
>    - lost approx 1dB of signal
> 
> antenna at 45 degrees roll:
>    - lost approx 1dB of signal
> 
> antenna pointing directly away from RedHill
>    - lost approx 4dB of signal, link still good
> 
> 
> 
> 
> ---------------------------
> test3: 5dBi 'round' omni
> 
> amplifier was enabled at Mt Ainslie
> 
> antenna in 'normal orientation':
>    - sig level at Mt Ainslie: -79dB
>    - sig level at Red Hill:   -72dB
>    - good video quality
> 
> antenna at 90 degrees roll:
>    - lost approx 9dB of signal at RedHill
>    - lost link completely at Mt Ainslie
> 
> antenna at 45 degrees roll:
>    - lost approx 9dB of signal at Mt Ainslie
>    - lost approx 9dB of signal at RedHill
>    - poor video
> 
> antenna pointing directly away from RedHill
>    - lost approx 13dB of signal at RedHill
>    - lost link completely at Mt Ainslie
> 
> 
> ---------------------------
> test4: 5dBi 'flat' omni
> 
> amplifier was enabled at Mt Ainslie
> 
> antenna in 'normal orientation':
>    - sig level at Mt Ainslie: -86dB
>    - sig level at Red Hill:   -80dB
>    - OK video quality
> 
> (antenna roll not tested)
> 
> ---------------------------
> test5: 3 element cloverleaf
> 
> amplifier was disabled and removed at Mt Ainslie. Radio at Mt Ainslie
> was reconfigured for TX power of 27dBm (max available on radio)
> 
> antenna in 'normal orientation':
>    - sig level at Mt Ainslie: -86dB
>    - sig level at Red Hill:   -87dB
>    - patchy video quality
> 
> antenna at 90 degrees roll:
>    - kept link, but very poor video quality
> 
>    
> The clear winner is the 3 element cloverleaf. While it doesn't have as
> much gain in the optimal orientation as the round omni does, it is much
> more robust when we have roll in the plane. We still need the amplifier
> for video link at 8km.
> 
> Next steps:
> 
>    - find out where we can get a couple of these 3 element cloverleaf
>      antennas
>    - build a housing for the cloverleaf so it doesn't get damaged/bent (at
>      least in transport)
>    - the the 900MHz cloverleaf as well (we didn't test it as we didn't
>      have a SMA -> RP-SMA adapter)
>    - see if we can source a 5.8GHz amplifier without the heavy inline
>      power supply. Amitay, can you tell us the make/model of this
>      amplifier?
>    - build a better antenna mount for the 20dBi patch
> 
> Thanks to everyone who helped today!
> 
> Cheers, Tridge
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> Canberrauav at canberrauav.com
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