Monday, June 11, 2012

Another antenna! 2m mobile for home use

So I had my HF antenna built, but I needed something for VHF and UHF so that I could participate in local nets on my repeater without sitting in my truck all night.  However, I live (for now) in a community with a restrictive HOA.  My solution was the same as with my dipole, hide it behind my house.  The quickest option was to purchase a small magnet mount antenna, but those require something metallic to attach the magnet to.  This also serves as a groundplane to help with the RF gain of the antenna.  My solution was to get a sheet of galvanized metal from my local Home Depot, and with a quick use of my tin-snips and some self-tapping screws, build a small shelf for the mag mount antenna to sit on.  However, this didn't give quite enough of a metallic surface to act as a groundplane, so I added what is called a counterpoise to the shelf to help with having a sufficient groundplane to allow the antenna to function with as much efficiency as possible.

My Parts List:

  • 1 sheet of galvanized sheet metal
  • 20" of 12AWG stranded wire

Time to Completion:

  • One hour or so.

Here is a pic:

I need to add a piece of 2x4 inside of the box part to make it a bit stiffer, but it works well as it is.  One note of interest, before I added the counterpoise, I was not able to hit the repeater that I prefer to frequent, after adding it, I am able to make contact.  Proper RF grounding is important!


Richard, KK4JDO

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