ABSTRACT
The basic superhet receiver shown in Figure 3.11
has an intermediate frequency (IF) of usually
either 455 kHz, 1.6 MHz or 10.7 MHz. In order
to achieve an acceptable degree of image channel
rejection (recall that the image channel is spaced
by twice the IF away from the wanted frequency)
a 455 kHz IF will generally be satisfactory for the
reception of frequencies up to about 5 MHz,
whilst an IF of 1.6 MHz (or greater) is often used
at frequencies above this. At VHF, intermediate
frequencies of 10.7 MHz (or higher) are often
used.
