RadCom Basics May 2022, Edition 28

20 RadCom Basics the coiled coax balun table for HF by Roy Lewallen, W7EL originally from theARRLAntenna Handbook. There’s even a RSGB Useful practical skills video on YouTube detailing how to build a simple HF balun https://www.youtube. c om / w a t c h ? v =WI we lWoD - T7w&list=PLmtHS6LSBybZimFeIe- jq4nsPmY4VkZiZh&index=2 The ferrite core based balun is probably more effective over a wider fre- quency range than the simple coiled balun. RadCom has recent- ly featured two very good articles on baluns, one by Mike Parkin, G0JMI and the other by Andy Nehan, G4HUE. Another article was found using the RSGB main site Search byTony Preedy, G3LNP. See references. There was some great work done by Steve Hunt, G3TXQ (sadly SK) that’s still available at http://karin- ya.net/g3txq/ He also put together an excel- lent paper on research- ing methods of testing different types of baluns with his results. Whichever balun you decide to install, fit it at the feed point, mak - ing sure of good mechanical and weather-proof connections. It may well add some weight to the centre of the antenna and ensure the wire used for the dipole can withstand it. Only a few years ago, I made my first HF coiled coax balun from the W7EL table for my 20m half–wave Figure 4: Coiled coax balun for 40/30m inverted-V dipole ready for installation