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 Wimo 2M Big Wheel 
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Post Wimo 2M Big Wheel
Do any of you Guys use the 2M Big Wheel, and if so where is it resonant?
My one is now resonant at 148 MHz with a reasonable SWR, but 1:2.5 at 144.3 MHz.
I took it down to clean/maintain, and may have disturbed something, I don't imagine the matching stub would influence resonance?
I have emailed Wimo, but from past experience they haven't bothered to reply.

Stewart


Tue May 31, 2022 3:16 pm
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 Wimo 2M Big Wheel 
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Post Re: Wimo 2M Big Wheel
It should be 144 to 146 by default.
And around 1.8:1 either end.
The tuning stub will of-course alter tuning / resonance.

This is from a home built one I made before wimo started making them.
Wimo's version shouldn't be dissimilar.
If it worked previously OK, and has gone high, then I would check the stub connection inside the black box.

The major part of tuning with these was with the element lengths.
As far as I remember the three elements are parallel to 35 ohms and the stub transforms to 50.

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Tue May 31, 2022 3:47 pm
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 Wimo 2M Big Wheel 
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Post Re: Wimo 2M Big Wheel
I stripped-down the ant. again, & found moisture in the hub.
I thought I'd sealed it adequately, but obviously not.
Anyone know what sealant they use?


Sun Jun 12, 2022 7:24 am
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 Wimo 2M Big Wheel 
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Post Re: Wimo 2M Big Wheel
Anything that stops water.
I've used silicon sealant , mastic or silicon grease to cover the exposed joints.
Or self amalgamating tape round the outside.

I generally only use the tape on coax connections and the silicon sealant on permanent joints.
The silicon grease is great to smear on anything and is easily wiped off with a rag.

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Sun Jun 12, 2022 10:30 am
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 Wimo 2M Big Wheel 
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Joined: Sat Jul 31, 2010 8:11 am
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Location: Nairn, Highlands IO87bn, or Tenerife IL18qa
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Post Re: Wimo 2M Big Wheel
M1MPW wrote:
Anything that stops water.
I've used silicon sealant , mastic or silicon grease to cover the exposed joints.
Or self amalgamating tape round the outside.

I generally only use the tape on coax connections and the silicon sealant on permanent joints.
The silicon grease is great to smear on anything and is easily wiped off with a rag.


I actually did use Dow Corning 111 silicon grease last time, but moisture still got in. I'll try using a bit more, then maybe use 3M liquid rubber outside the hub. Only problem is the liquid rubber is a bugger to remove if it happens again.

Cheers Mark.


Sun Jun 12, 2022 11:20 am
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