|
The theory behind the "height gain" observed
using small LF active antennas at different heights has to do with compression
of the near-earth LF potential gradient caused by the grounded "mast" holding
the antenna.
The essential bit is that there is a grounded
connection between the antenna and receiver, which may be just the outer of the
co-ax cable. It would be an interesting experiment to repeat the "height gain"
experiment without any connection to ground. This could be done by building
an active antenna with a little transmitter to re-radiate the received LF signal
(on 2.4 GHz?) and poking it up using a fibreglass mast. If the theory is
right then there wouldn't be any height gain. Might do it myself sometime but
anyone else interested?
Walter G3JKV.
| 