LaPaglia's IPAQ/GPSr

Reradiating Antenna 

My version of the Reradiating Antenna for my Co-Pilot GPSr. 

This is constructed in a small project box. The smaller box contains 2 AA batteries as the 3 volt power source. I used the same design as brdad. I am currently using a .0068mf cap as this is the smallest one I have. The BNC connector on the left is for the powered antenna and the one on the bottom is for the transmitting antenna.

Basic internal view. its hard to see but the coil is located at the end of the red wire.

The transmitting antenna is 190 mm piece of steel coat hanger. I am going to change it for a piece of 12ga copper wire. It works great as is but is a little too stiff. 

My IPAQ/GPSr jacket sleeve with the transmitting antenna hooked around the Quad-Helix antenna. I secure the cable to the belt clip on the back of the GPSr.

The transmitting antenna cable is 3 feet long. The powered antenna cable is 16 ft long. If you buy one I suggest getting the 3 or 9 ft length. I place the box in my pocket and the 3 ft. cable is more than long enough for any where I use the GPSr.  I have run this constantly for 253 hours on 2 AA batteries before it stop working, That is more time than I will ever use on one day or even one week of geocaching. For all the important information please see. brdad's page. This is a very good page with all the needed information.

The above pic is modified from a drawing done by Dave Martindale <davem@cs.ubc.ca>

Above is the basic circuit. L1 is a hand wound coil, 6 turns of #26 wire wound on a 3/32 drill bit. each coil is separated by the width of the wire, The entire coil section is about 6mm long. keep the leads as short as possible on the end that connects to the in connector. C5 is a .0068 uf ceramic cap. As you can see from the pictures above I kept the distance between the center conductors of the in and the out as short as possible. 

All I have left to do is change the box so I can put the batteries inside. My results have been as good or better than the ones shown by brdad, Do look at his page the graphs are quite informative.

End result. if you have a GPSr what does not allow for an external antenna, build one of these. For the $30.00 it cost me its a great tool