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eHam Forums => Antenna Restrictions => Topic started by: CTHAM on April 24, 2009, 09:20:39 PM



Title: Would this work? (J-pole antenna)
Post by: CTHAM on April 24, 2009, 09:20:39 PM
I live at a apartment in which I can't mount any antenna onto the brick surface also I'm on the first floor and my window is about 11 Ft off the ground.

I was thinking about since I need to get a window A/C unit I can mount some type of antenna so I can use a antenna without me having to hang myself out the window just to use my HT. This building is concrete and metal so very little if anything is able to reach outside.

However one issue I have is my screen is a swing out screen.. I'd like to use 2 meter J-pole for APRS but how can I mount it without it risking falling over? I was thinking drilling the new window A/C and using U-bolts?

Or maybe some type of Mag mount antenna?


Title: Would this work? (J-pole antenna)
Post by: VY1DM on April 25, 2009, 03:53:05 PM

If the case of the AC is steel, and the size is bigger than ~18" square, a 1/4 mag mount should work off it directly.

If it's smaller than that, but has a steel case, what about two mag mounts on the side of the AC case, one above the other, to the 'cold' end of the J pole?

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Title: Would this work? (J-pole antenna)
Post by: CTHAM on April 25, 2009, 05:37:00 PM
hmmm well the height of the unit is 12.5" and the width is 18.5" I have to double check to make sure the body of the A/c will clear the swing out screen or that would be a issue of the A/C not being wide enough so the antenna would never clear the screen.

And for the mag mount what is keeping the j-pole secure? it has to at least pass a 25mph gust.


Title: Would this work? (J-pole antenna)
Post by: K4JC on May 04, 2009, 11:08:54 AM
As long as the case of the AC unit is metal (steel or other material a magnet will stick to) just put a 5/8 wave mag mount on it. Even a small window AC unit should provide enough of a ground plane for the antenna to work. Plus a 5/8 wave will give you a bit of gain. You won't set any VHF distance records, but at least your antenna will be outside!


Title: Would this work? (J-pole antenna)
Post by: WB4LFC on May 06, 2009, 12:21:41 AM
I would go with K4JC's suggestion.I have tried this while on vacation in a condo and it worked great.


Title: Would this work? (J-pole antenna)
Post by: K4CAV on May 06, 2009, 08:04:12 PM
I agree with K4JC. Ditch the J-pole and go with a 5/8 wave mag mount. I don't understand the screen issue. Can you do away with the screen now that you have a window AC unit and mount the antenna on top?
If not, you mention that the window is 11' above ground, you could just mount the antenna to the bottom of the AC unit.

K4CAV / Jim


Title: Would this work? (J-pole antenna)
Post by: CTHAM on May 07, 2009, 07:03:51 AM
The screen is not a up/down screen it's one that swings out..

the screen would be resting on the back part of the AC unit

I was going to get the arrow jpole