My first #HB9CV #antenna, believe it or not, made from 5mm brake lines and a foot of 15mm copper pipe 🙂
I need it for a 70cm radio #foxhunt event in a couple days - looked different places for design guidelines, some of them came up with quite different results 🤷🏼♂️🤨
Decided to just have go at it, based on a combination of what I could find in the legendary #Rothammel antenna book and some online sources and it turned out quite well 😃
Resonance is a bit low, 431MHz, but it’ll do fine as a direction finding device: what I really want is the characteristic kidney shaped radiation pattern, allowing me to turn the antenna backwards, looking for a minimum in the received signal.
Funny to see how the #smithchart impedance plot has a distinct turn at the resonance frequency 🤓
#rfengineer #hamr #antennadesign #testandmeasurement #electronicsengineering
