|National SW-3 Plug In Coils|
| Unlike more
modern radio's which allow you to change bands at the turn of
a single bandswitch, the National SW-3 changes bands by
plugging in a pair of coils.
The operator turns off the radio, lifts the hinged top lid,
and replaces the coils with the desired frequency set.
There are two kinds of coils, a "general coverage" coil which
provides a full dial over a wide frequency range, and the
"bandspread" coil set which provides a full dial over a narrow
frequency range for fine tuning the ham bands.
|SW-3 coils are identified by several possible ways. Earlier coils had a colored dot applied to the bottom of the coil form, in-between the pins. It may or may not have the coil number stamped on the bottom. Along the top edge of the coil form, there is an indentation that may also be colored in. Later coils had a number stamped on the bottom and may or may not have a colored bottom dot and the top edge colored in. See the table below for coil frequency identification.|
|Coil information from an article by William Fizette K3ZJW, titled "Those National 6-Prong Plug-in Coils"|
|Back to National SW-3 Thrill Box|
Last Update: 11/25/2020
Web Author: Scott Freeberg WA9WFA
Copyright ©2020 by Scott Freeberg WA9WFA - ALL RIGHTS RESERVED