Originally Posted by careyer

Hi there

i've build one of those Skew Planar Wheel for my 910Mhz 800mw Hobbyking RX/TX Set but the result is extremely bad. ...

That antenna looks too small for 910 Mhz, more like a 1280 Mhz antenna. What dimensions did you use?

OMM

hi OMM ...
if the rx casing is anything to go by (i assume they are the same size as mine) then his antenna size looks about the same as mine

Originally Posted by careyer

Hi there

i've build one of those Skew Planar Wheel for my 910Mhz 800mw Hobbyking RX/TX Set but the result is extremely bad.

Though i tried to keep tolerances as small as somehow possible (<= 1-2mm) it does not give me more than 200m of range in direct line of sight. Tried all channels 1-4 (910-1040 MhZ) and channel 3 ist best. The Standard antennas even give me slighly more range and more robust signal. Any Idea what might be wrong?

Here's a pic of my two antennas:


P.S: 900M Mhz is the primary band for cellphones right over here. Might this affect the range that much? Cellphones are allowed to send 2W .... basestations about 8W.

I have a hard time seeing from the picture, but it looks to me like one is LHCP and the other is RHCP. The interactions between these antennas will be -18 db or so if this is the case.

-Alex

...

just to post also here and say that the "magic combo" CP/SPW work like no other antenna....

CL and SPW antenna on my DIY Delta FPV wing (11 min 43 sec)

is this the future standard antenna in FPV ?

yes with no doubt


Jay

i am currently running 900mhz SPW on my vrx
to prevent wire clutter around myself ... i have gotten a FOXTECH AIO with built in 5.8 vrx
i then placed a 25mW 5.8vtx to relay the video from my 900mhz system to my goggles

question ...
how would performance compare if i just place the 900 CL on a tripod on the ground vs tripod on the roof of my car/van ?
the height of the tripod would be about 5ft or so
my current fly field is asphalt car park with buildings with some curve and flat metal roofs but these buildings are nothing higher than 3-4 storeys

thanks ...

On the ground would be better. Eventhough the Cloverleaf/SPW reject multipath well, placing it on a huge metal reflector will still hurt performance.

-Alex

Originally Posted by IBCrazy

On the ground would be better. Eventhough the Cloverleaf/SPW reject multipath well, placing it on a huge metal reflector will still hurt performance.

-Alex

Not sure i agree Alex.

I have my VRX mounted on a tripod that stands on the roof of my van; 1.2m higher than the roof. I have also tried with the tripod on the ground and have to say it seemed better on the roof.

I have been led to belive that omni antennas work best when they are mounted up as high as possible (up to a point) and this does seem to be the case with my CL, SPW combo.

You can see my setup at the end of this vid (4:52); only close in flying in this clip but i have been out to near my 35MHz range limit and the video was still great

FPV on the beach (5 min 28 sec)

A stand on the roof is fine, but on the ground is better. Well, assuming the Fresnel zone is clear. I guess I figured that there would be no objects he'd be flying over that would disturb the Fresnel zone.


-Alex

i will try both this weekend and let u guys know
there is also a telco GSM 900/1800 200m from where i stand .. hehehehe

Alex, can i put SPW in plastic case with 1mm wall thickness? 5.8Ghz 200mW. I want to build compact ground station and dont want to brake a SPW antenna, so i need to put it in plastic case.

Originally Posted by vipix

Alex, can i put SPW in plastic case with 1mm wall thickness? 5.8Ghz 200mW. I want to build compact ground station and dont want to brake a SPW antenna, so i need to put it in plastic case.

Yes.

How does my SPW look? @ 1280 RH polarized

lobes are not angled vertically enough & you need to pull them around so there's a more even overlap.

otherwise good.

Originally Posted by Toysrme

lobes are not angled vertically enough & you need to pull them around so there's a more even overlap.

otherwise good.

Man you got some mad ability for spacial visualization in your brain! I've only built 2 5.8ghz SPW's and it looks like he's got his 45 degrees going on to me but anything other than an oblique angle and it gets hard for me to tell either way!

Cheers