On 6 ene, 09:55, "Norbert M." wrote:
When matching a very short whip one gets a big reading but
further down the road is could all be dissapeared.

Can a closeby fieldstrenght measurement be done ?
The magnetic field is also great with a short whip.
Hello Norbert

A similar question appeared some days ago in a Dutch amateur radio
newsgroup.

As Roy also mentioned, when you do not change the antenna (inclusive
any ground system) and also not change the E-field meter position and
orientation, but only change the matching, every dB increase in the
near field, will give the same dB increase over distance. Assuming
that your matching network does not produce significant E-field.

Determining the radiated power from near field measurements is
theoretically possible, but not easy in real world for most
amateurs.

You might measure the field strength at a certain (near field)
distance. Run an EM simulation for your antenna construction
(inclusive ground system if present). Compare the simulated (near
field) E-field with the measured value. From the radiated power (in
the simulation) you can calculate the radiated power from your
antenna.

Best regards,

Wim
PA3DJS
www.tetech.nl