Hello Paul,
Noise received on your TX antenna is re-transmitted and this is responsible for
the increase
in noise level on your RX antenna. One way to get rid of it is to detune your
TX antenna on
receive.
I have been using an active E-probe antenna since 2004 with very rewarding
results on LF / MF,
albeit mounted just 6 meter from my house. The band noise from the antenna at
477 kHz is 14 dB
over the noise floor of my PERSEUS, so sensitivity is more than needed.
There is no need for a good radio earth with this type of antenna, due to the
small
capacitances involved, typical 3 pF.
This antenna is prone to common mode problems. I have solved this by connecting
the shield of
the coax to a ground stake at the bottom of the mast and near the house.
Requirements for this
ground are modest. On poor soil one square metre of chicken wire will work
already. A suitable
common mode choke, e.g. 20 turns RG174 on a FT-140-77 toroid can help as well.
To achieve best results some experimentation is on order, which is time well
spent!
73,
Roelof Bakker, pa0rdt
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