On 24 feb, 00:13, TOF wrote:
I have a (home built) 40 m ground plane with the base elevated about 8
feet and with 7 elevated sloping radials. *The 50 Ohm feedline drops
straight down the 8 feet and then runs on the surface of the ground.

Would *a choke balun at the feed point be advisable?

W0BF

Hello,

When that 7 radials don't touch ground and are about 1/4 lambda in
size, you have a very good floating ground. It will depend on the
length of the radiator whether you get significant voltage between
your floating ground and Earth.

When using a 1/4 lambda radiator (or longer with a series capacitor
and transformer) in my opinion you don't need it. During JOTA we use
a 0.4 lambda radiator over 6 elevated quarter wave radials (7..8 ft).
Last year we only used three of them. Moving high impedance cores
(for 7 MHz) along the coaxial feeder did not change VSWR. Also a good
diode probe with whip didn't show common mode issues with the coaxial
feeder.

Best regards,


Wim
PA3DJS
www.tetech.nl
without abc you have a functioning email address.