Practical_Antenna_Handbook_0071639586

C h a p t e r 1 4 : r e c e i v i n g A n t e n n a s f o r H i g h F r e q u e n c y 361
some form of selectivity is applied at its front end. Even a high-end receiver will benefit
from having a low-power antenna tuner (ATU) inserted in the path between it and a
longwire antenna.
The longwire antenna is covered at length in Chap. 8 (“Multiband and Tunable Wire
Antennas”) as a transmitting antenna, but some of the installation considerations there
are of little importance for a receive-only installation. In particular, when used for transmitting
a longwire must be operated against a good RF ground system, but if used only
for receiving, the grounds associated with the receiver’s power cord are probably sufficient
at all but the highest frequencies.
Because the longwire enters the structure where the receiver is located, it tends to
faithfully pick up signals from any of the incidental radiators nearby: wall adapters,
Ethernet circuits, computer power supplies, etc. In today’s electromagnetic environment,
this may turn out to be its greatest shortcoming.