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Vertical Antennas for 6M and 2M

posted Nov 7, 2018, 7:45 AM by L Gray   [ updated Nov 7, 2018, 7:46 AM ]
The Squalo antennas for operating on the lower portions of the 6 and 2 meter bands fulfilled a need for inexpensive and easy to build, horizontally polarized antennas. These antennas are not suitable for FM as most stations use vertically polarized antennas on this mode.  With the recent interest in 6m FM there was a need for a vertically polarized antenna. There are several examples on the Internet.  The November Spark Gap article submitted by Jim, WA1GPO and Don. N1JCT, provides information on the construction of 6m and 2m versions

The first antenna presented in the Spark Gap article is a version for 6m ‐ built by 
Don (N1JCT) and Jim (WA1GPO). It is self‐supporting, easy and inexpensive to build. The antenna is fabricated from coaxial cable, hookup wire and PVC pipe.  This is a coaxial half‐wave antenna. The design makes use of the ‘skin effect’ property of RF in a conductor. In this case, RF is flowing to the antenna elements on the ‘inside’ of the coax cable shield; the ½ wave antenna is formed by the ¼ center conductor of the cable and the ¼ current flowing on the ‘outside’ of the coax cable shield. The current on the outside is limited by the RF choke – a spirally wound section of coaxial cable, 20 turns on the 1.25 inch PVC pipe. Each element, shield and center conductor are 50.5 inches in length.

A 2 meter version of the coaxial half‐wave antenna was also fabricated and tested. It was built into a ½ inch (.875 OD) section of PVC pipe about 48 inches long. It also utilizes an RF choke (15Turns) wound on the pipe; the choke is about 3.25 inches long. The ½ PVC can be adapted to a larger 1.25 PVC pipe (see the 6m version) or can simply be hose clamped to a mast. Note – the coaxial choke must be above any metal supports. The lower (coaxial shield) element is 16.75 inches and the upper (center conductor) element is 17 inches. Construction is similar to the 6m version, the pictures in the Spark Gap article tell the story.   Fabrication is easier with a 2 part PVC pipe.

See the November Spark Gap article for complete details.