Mecworks Photo Gallery :: A j-pole build process for GMRS frequencies (462.550MHz

A j-pole build process for GMRS frequencies (462.550MHz - 467.725MHz)

20 images in this album on 2 pages

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This is a photographic guide to building a GMRS frequency j-pole antenna (462.550MHz - 467.725MHz).

This is now covered in an article located here:http://blog.mecworks.com/articles/2005/02/27/gmrs-j-pole/ There are more picrtures and better descriptions in the article. Thanks!

IMPORTANT: 1) There are two pages to this album. 2) There is a more detailed description of contruction techniques used with the larger images, so click on the thumbnail and take a look at the larger image.

The antenna's radiating elements are made from a single standard car-radio antenna. This makes it easy and cheap to build. The design could easily be adapted to the ham 70cm 420-450Mhz band. Although one might need to use two car antennae instead of one to make the "J" and still have enough antenna material left for the main radiating element.

"So what good is it to me?" you say? Well, this antenna is desinged to work with the GMRS radios you get at sporting good stores (REI, Cabelas, Gallians, etc) and will greatly increase your range (by miles). NOTE: 1) you can only use this antenna with GMRS or GMRS/FRS combo radios which are built with removable antenna (you cannot use this antenna on or modify an FRS-only radio) and 2) you need an FCC license to use GMRS radios in the US (read the packaging on the radios you get for more info) and know your local laws to make sure it's legal to use this!

Feedback welcome...send email to comments _aatt_ mecworks daut com

Standard stainles steel auto antenna.

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Cutting the "J" lenght.

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The first bend of the "J" section.
Last comment 02/21/05.

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Another measurement closeup.

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Final bend in the "J".

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Completed "J".

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Getting ready to silver solder.

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Preliminary silver solder complete.

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Stainless steel wire used to strengthen joint between main antenna radiator and "J".

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Closeup of stainless steel wraped joint, ready for solder.

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Finished solder joint.

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Close up of the joint and my mini-torch.

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The cleaned joint.

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Brass collars used to connect the coax to the j-pole and adjust for best SWR.

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RF choke (5 or 6 turns on 1.75") and brass collars.

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Plexiglass bridge between "J".

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