RadCom Basics May 2022, Edition 28

RadCom Basics 27 will cover more than one band at once, with elements for both 2m and 70cm, or 6m and 4m. Others are single band. Yagis are typically setup,so they’re horizontally polarised for SSB/CW/ Data and are the choice if you want to work longer distances. You can also use a Yagi vertically polarised, but this is only typically used for FM. Serious contesters, Earth Moon Earth (EME) enthusiasts and DXers will all choose a Yagi on the VHF/ UHF bands. If you want to increase the gain of a Yagi, you typically have two options; either increase the number of elements and/or stack more than one Yagi together.There is a point of diminishing returns though. BigWheel This is an unusual variation and allows a bit of gain, while giving you near omni-directional radia- tion and horizontal polarisation. It looks like a big wheel, with three folded elements pointing in each direction. Wimo sells one for 2m [3] which provides 3dBd gain. These are good if you want to ra- diate an equal SSB/CW/Data signal in all directions at once and re- ceive the same. They also dispose of the need for a rotator. Conclusion This article isn’t intended to be ex- haustive or particularly technical, but rather an initial primer on the major types of VHF antenna avail - able for your home QTH.Antenna theory and construction is a hob- by in itself! Many new amateurs may start with a simple collinear for FM work and then move onto Yagi’s. Some will even use both to work local stations using FM on the collinear and SSB/CW/Data for DX on the Yagi. Antenna choice is always a bit of a constrained choice within the UK, you have to balance performance against what you can get away with! Web links [1] Diamond V2000 collinear for 6m/2m/70cm https://www.hamradio. co.uk/aerials-antenna-manufactur- ers-diamond-antennas/diamond/ diamond-v-2000-pd-2592.php [2] PowAbeam 15 element Yagi for 70cm https://thedxshop.com/ product/powabeam-ukac-432-15- 432mhz-antenna/ [3] Wimo Big Wheel antenna for 2m https://www.wimo.com/en/big- wheel-2m