4A

This Amateur Radio Transmitter was introduced in the October 1933 issue of QST. It is a crystal-controlled CW-only transmitter capable of 20 watts RF output. The crystal and associated band-changing coils were plugged from the top of the unit.

The 4A was a kit, all parts included, however, you were responsible to purchase the tubes separately.

Construction

Like many home-assembled projects - this unit had no cover, top, sides or back.

As Advertised

The 4A was first introduced in the April-August issue of Collins Signal magazine.

The production units were a bit different than the Museum's artifact. The Power Amplifier Neutralization control was moved from the interior to the front panel. The crystal was moved from inside to a socket on the front. Notice this particular unit did not have a manufacturers plate - that we can see.