Since citizens band is operating at about 27 MHz, the standard i.f. of .455
MHz allows an image of twice the i.f. frequency (.91 MHz). This image is
not rejected by the tuned circuits of the cb rig. So, double conversion is
used. In this specific case, the selectivity is not increased, but the
image rejection is. Often the first i.f. is in the 5 to 10 MHz range.
Recently, with the use of low noise mixers, the first i.f. can be at 40 MHz
or higher, which provides excellent image rejection.

Bottom line is that most cb radios that are average or better use double
conversion. In the case of your GE unit, the marketing department decided
to add a little hype to an rather ordinary cb unit and called it a Double
Super Hetrodyne. Is your radio a special radio? No. Is it worth more? No.

Colin K7FM