[HamWAN PSDR] Official azimuth radiation patterns published

Bart Kus me at bartk.us
Sat Feb 9 12:10:17 PST 2013


Hello,

Stayed up way too late last night running radiation pattern measurements 
in the great anechoic outdoors.  The new patterns look much healthier 
than the echo-ridden indoor measures.  I was also able to test 2 new 
antennas.  Not sectors, but the 21dBi and 27dBi grids from Laird.  All 
the results are linked at the top of the Antenna Analysis 
<https://www.hamwan.org/t/tiki-index.php?page=Antenna+Analysis&structure=HamWAN> 
page, but here are the direct links:

  *
    ARC ARC-VS5818SD1
    <https://www.hamwan.org/t/tiki-index.php?page=ARC+ARC-VS5818SD1&structure=HamWAN>
  *
    Laird SAH58-120-16-WB
    <https://www.hamwan.org/t/tiki-index.php?page=Laird+SAH58-120-16-WB&structure=HamWAN>
  *
    Laird GD5W-21P
    <https://www.hamwan.org/t/tiki-index.php?page=Laird+GD5W-21P&structure=HamWAN>
  *
    Laird GD5W-28P
    <https://www.hamwan.org/t/tiki-index.php?page=Laird+GD5W-28P&structure=HamWAN>


A few conclusions can be drawn from this official data:

1) The ARC sector is complete nonsense.
2) The Laird sector is lookin fine!  The F/B is not as bad as I had 
feared.  Although the "120 deg" beamwidth claim looks to be based on 
-6dB points, not your typical -3dB points.  Strange.  I'm still 
concerned about its -3dB FR @ 5.885GHz.
3) For the $25 price premium over the 21dBi model, I'd say the 27dBi 
Laird grid is well worth it.  I have a 31dBi grid on the way which would 
only cost $6 more than the 27dBi Laird.  4dB for $6 is a no-brainer.  
We'll see how it measures though.

Next up, before the new antennas arrive for testing, I wanna re-run the 
frequency response measurements using the outdoor environment and verify 
that there are no changes in the curve shapes.  That will confirm the 
indoor FR measurement process is not suffering from echo effects.

--Bart

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