Difference between revisions of "4A"
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| − | This | + | This Transmitter was introduced to the amateur radio community in the October 1933 issue of QST. |
It is a crystal-controlled CW-only transmitter capable of 20 watts RF output. | 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 crystal and associated band-changing coils were plugged from the top of the unit. | ||
| + | However, the production units were a bit different than the Museum's artifact. | ||
| + | The Power Amplifier Neutralization control was moved to the front panel as well as the crystal module. Notice this particular unit did not have a manufacturer’s plate - that we can see. | ||
[[File:4A front m.jpg|center|This unit is now in the UTC museum.]] | [[File:4A front m.jpg|center|This unit is now in the UTC museum.]] | ||
[[File:4A upper-left m.jpg|center|Internal View]] | [[File:4A upper-left m.jpg|center|Internal View]] | ||
| + | == Construction == | ||
The 4A was a kit, all parts included, however, you were responsible to purchase the tubes separately. | The 4A was a kit, all parts included, however, you were responsible to purchase the tubes separately. | ||
| − | + | Like many home-assembled projects of the day - this unit had no top cover, sides or back. | |
| − | Like many home-assembled projects - this unit had no cover | ||
== As Advertised == | == As Advertised == | ||
<center><b>The 4A was first introduced in the April-August issue of <i>Collins Signal</i> magazine.</b></center> | <center><b>The 4A was first introduced in the April-August issue of <i>Collins Signal</i> magazine.</b></center> | ||
Revision as of 21:02, 30 March 2020
This Transmitter was introduced to the amateur radio community 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. However, the production units were a bit different than the Museum's artifact. The Power Amplifier Neutralization control was moved to the front panel as well as the crystal module. Notice this particular unit did not have a manufacturer’s plate - that we can see.
Construction
The 4A was a kit, all parts included, however, you were responsible to purchase the tubes separately. Like many home-assembled projects of the day - this unit had no top cover, sides or back.
As Advertised
The 4A transmitter marks the entry of the COLLINS line in the extremely low-priced field. The 4A uses a 47 crystal oscillator and parallel 46's in the power amplifier permitting an output of 18 to 20 watts on 1.7, 3.5 or 7 me. The power amplifier is operated on the crystal frequency in each case. Despite its low cost, the 4A embodies the mechanical and electrical refinements found in the larger COLLINS transmitters. A separate power supply is used for the oscillator to reduce frequency "chirp." Standard COLLINS plug-in coils are employed. A single Weston meter is provided with a switching arrangement to read plate and grid currents. The 4A is ideal for an amateur who wants to start out with a minimum investment and yet have a transmitter which will deliver a high quality C. W. signal. The 4A can also serve as a stand-by transmitter in a high-powered station to be used when full power is not required. Really surprising results can be obtained and amateurs who are accustomed to think in terms of kilowatts can get a great deal of service and amusement from one of these little transmitters.
