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Author Topic: The PAR OA144 2m Omnidirectional Antenna.  (Read 4640 times)

gil

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The PAR OA144 2m Omnidirectional Antenna.
« on: July 24, 2017, 01:36:41 PM »

Gil.

cockpitbob

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Re: The PAR OA144 2m Omnidirectional Antenna.
« Reply #1 on: July 24, 2017, 02:55:50 PM »
Nice vid Gil.

I see what you mean about the U-bolt not having threads that go down far enough.  Of course you always have the option of using a stack of washers under the nuts.  I had to do this once and I glued the washers together so I wasn't always fumbling with them.

At first I thought it was a Moxon and wondered what the Omni part was since a Moxon has a big front-back ratio.  I never gave much thought to the difficulty of doing a horizontally polarized omni, but it can't be done with something as simple as a ground plane vertical or J-pole like you can use for a vertically polarized omni.  This is clever, and small.   Then I thought "I wonder how hard it would be to convert it to a Moxon.", but I looked it up but the square pipe would need to be about twice as long. 

BTW, in the background I think I see several masts ranging from about 3M to 6M tall on houses.  Are there a lot of radio operators there or are they for TV or something else?

caulktel

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Re: The PAR OA144 2m Omnidirectional Antenna.
« Reply #2 on: July 24, 2017, 06:55:05 PM »
Great video Gil,

I contacted Dale Parfitt about your antenna after watching your video and to get pricing and some info. He got right back to me with this:

These antennas are an entirely different design from the classical
  shortened  half wave loops.
   Omniangles use an electrical length LONGER than a half wave and an
  isosceles  triangle shape to synthesize a perfect omnidirectional pattern
  (within +/-
   0.5dB). The square and round loops have an elliptical pattern with front
  to  side ratios of 5dB and more! We hope to soon have plots taken at the
  Florida  Motorola anechoic chamber of all of the commercial "omnis" on our
  site
   Our largest clients are commercial and military. As a result, all of our
   hardware is stainless, all metal surfaces are either polished or
   jitterbugged. The connectors are silver/teflon. The Omniangles are the
  only  commercial series that have a built in balun and do not require an
  insulated  mast in order to prevent mast/feedline radiation.

I think I will be buying one of these as soon as I can afford it. I just bought a HF Mag Loop, so I have to recover from first.

Joel
N6ALT

gil

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Re: The PAR OA144 2m Omnidirectional Antenna.
« Reply #3 on: July 24, 2017, 08:01:05 PM »
Thanks Bob, washers are on my shopping list! I need butterfly nuts too, but can't get standard threads in France. Thankfully there is the Internet!

Joel, make sure you tell Dale P. Where you heard about it ;-) maybe he'll send me another antenna to test! I bought this one...

Gil.

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htfiremedic

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Re: The PAR OA144 2m Omnidirectional Antenna.
« Reply #4 on: July 24, 2017, 09:18:56 PM »
Nice!  Thanks for the info!


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