[Elecraft] Low-Noise Reception: was "new product idea: phasing unit"

[Ron D'Eau Claire]

On the general subject of low noise reception, the K2 with its =
preamplifier
is admirably equipped for an on-the-ground or even an 'underground' =
antenna.


No kidding! These antennas make wonderful low-noise receiving antennas =
that
help weak signals pop out of the background QRN. (And, if you accept a =
three
S-unit drop in signal compared to a typical dipole in the air, you can
transmit on them - see works published by C.H. Targett, G6PG, in the =
RSGB T
& R Bulletin in 1927 or by W0YBF published in QST sometime in 1965 I =
believe
it was).=20

Typically, signals on such antennas are 12 to 18 dB below an in-the-air
antenna, but with a much, much better signal-to-noise ratio on receive. =
The
K2's preamp more than makes up for the loss in receiving signal strength
with most such antennas. If you have the 160 meter option installed, =
you're
all ready to use a separate receiving antenna.=20

Used for receiving, these antennas can be non-resonant: you don't need =
to
cut them to a certain length. Some ops simply lay out old coax on the =
ground
with the far end un-terminated and the receiver end connected to the rig
with a coax connector. If you can lay the wire out in a straight line =
over a
long distance, it will show directivity favoring signals off the "end".
However, few of us can put out a couple of hundred feet of wire in one
direction, so expect it to be "non-directional" - just quieter than your
in-the-air antenna.=20

Of course, precautions to make sure you don't pick up local QRN from =
within
your shack are important if you have lots of noise-sources around the =
house.


Ron AC7AC