Lmst

I won a book. On the right is the 13th edition of the #Rothammel Antenna Book. This is THE antenna book here in Germany; every amateur radio operator I know has at least one copy of it. Almost 1,500 pages of concentrated knowledge.

On the left, for comparison, is my old copy (10th edition, published 1984 by the Military Publishing House of the GDR).

Thanks to DARC-Verlag and the HF-Department of the DARC!

Btw: there is a english edition too: https://rothammel.com/Rothammels-Antenna-Book

Two books on a table. On the left the 10th edition of the Rothammel Antenna Book; on the right the 13th edition.

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