Ham Radio Forum

I have installed a 40m endfed antenna with a 9:1 balun, in form to transform the high impedance down to abt. 50 Ohms. Does it make sense to implement a set of radials?
If yes, what length?
Tkx for support.
Kind regards, Mauro

Is the antenna vertical or horizontal to earth? A vertical antenna could benefit from radials because they reduce radiated signal ground losses even though an antenna feed impedance is high enough that resistance losses from feed-line currents into a ground rod wouldn't be significant.

Ideally, if you want to reduce ground radiation losses into the earth as much as possible the ground radials should be a half-wave or more long. However, radials are rarely made the long, because there is little additional benefit after the first 1/8 wavelength or so. That happens because the velocity-constant of burried radials is so much lower than for a free space antenna wire that an 1/8th wave long length of burried wire may be nearly quarter-wave resonant.

Tom

Many thanks Tom
The antenna is placed horizontal. I will dig the garden for 1/8 wavelength (middle of bands) and make some measurements.
txs and best rgds, Mauro