Here's a neat little project that will prove useful for portable operation or improving your HT in the fringe areas.
1. Cut a piece of TV twin-lead 55 1/8" long.
2. Clean off 1/2" of insulation at one end. Twist the exposed ends together and solder.
3. Measure 16 5/8" from the shorted end and remove 1/4" of conductor on one side.
Note: You now have a half-wave radiator connected to a 1/4 wave stub. Now a you have to do is connect a piece of 50 ohm coax to the 50 ohm impedance point on the stub.
4. Cut a piece of 1/8" RG174U coax about 6' long. (RG58U is OK but it doesn't fit in your pocket so we.) Put an antenna connector on one end and open up the other end for making connection to the stub.
5. Open the two twin-lead conductors up at a point 1 1/4" from the shorted end and solder the coax braid to the short conductor and the coax center lead to the long conductor. Cover the joint with electrical tape.
6. Punch a small hole at the open end of the twin-lead to permit using a string to support the antenna from any convenient pace.
Results will suprise you. Expect several "S" units improvement over the pull-out whip or even more over the rubber duckie. This version is said to work pretty well on 70 cm also.
Version Two
2 Meter and 70cm J-Pole
A=54.25"
B=15.75"
C=0.25"
1. Follow the general directions above. Cut the overall length to 54 3/4" with the long element being 54 1/4" after striping the 1/2" to short the ends.
2. Cut the notch up 15 3/4".
3. Cut the feed point up about 1/4"
