The Heathkit Virtual Museum Home History Hi-Fi & Stereo Ham Radio Test Equipment Computers Other

DX-20 CW Transmitter


  • 50 watts plate power input to 6DQ6A final.
  • Straight-CW operation—maximum efficiency and clean output signal.
  • Crystal controlled—or may be excited from external VFO.
  • Covers 80—40—20—15—11—10 meters.
  • Single-knob band switching—no coils to change.

Here in the model DX-20 transmitter is a transmitter that has been designed without compromise, exclusively for CW work. It features an entirely new circuit over the preceding model, and is one of the most efficient little transmitters available today. It's the ideal rig for the novice or for the advanced-class CW operator. Just the ticket for any radio amateur interested in CW work who appreciates a good clean signal, and wants the most "watts-per-dollar" in his ham shack.

The plate power input of the model DX-20 is 50 watts, and the rig covers 80, 40, 20, 15, 11 and 10 meters. It is designed for crystal excitation but an external VFO may be used. A pi network output circuit is featured for matching antenna impedances between 50 and 1000 ohms. It employs a 6DQ6A final amplifier, a 6CL6 oscillator, and 5U4GB rectifier. A great deal of thought went into the design of this rig. It features short leads, horizontal tube mounting, a very efficient band change switch arrangement, and many other evidences of careful design. The transmitter incorporates single knob band switching, uses potted transformers, and high quality components throughout. Truly, the CW man's transmitter. Top performance for minimum investment.

Measuring only 13" W. x 8½" H. x 7" D., the DX-20 is enclosed in a tight steel cabinet to minimize TVI. The front panel was designed with full consideration for convenience of operation. The two large knobs at each side of the panel are for tuning the oscillator and the final amplifier. The band change switch is in the center of the panel, just below the meter switch. The easy-to-read meter indicates final grid current or final plate current. Across the bottom of the panel from left to right, are the main "on-off" switch, the "on-standby" switch, the variable "loading control", to match various antenna impedances, the "tune-operate" switch, and the key jack. The "tune-operate" switch provides a means of switching on the oscillator without the final amplifier being on; so the operator can locate his own signal on the band without going on the air, and tune the oscillator stage before the final is on. The crystal socket is located inside of the cabinet, and a "snap-out" plug is provided on the left panel of the case for convenient access while still maintaining "tight" construction. This minimizes radiation outside of the case, lessening the possibility of television interference. The antenna output is on the back chassis apron. In addition to being an attractively styled transmitter, and featuring an "optimized" circuit, the DX-20 is very easy to build. This probably would not be of great concern to the "old-timer" but it is important to the novice or beginning ham. The construction manual contains complete step-by-step directions for assembly. Large pictorial diagrams are referenced all the way through, and it is not necessary to read a schematic diagram. We are sure you will agree that this CW transmitter cannot be matched for over-all quality and efficiency on the market today. Shpg. Wt. 18 lbs.

Specifications—RF Power Input... 50 watts CW. Output Impedance... 50-1000 ohms. Output Coupling... Pi network (coaxial). Operation... Crystal—external VFO. Band Coverage... 80-40-20-15-11-10. Tube Complement... 5U4GB rectifier, 6CL6 oscillator, 6DQ6A final amplifier. Power Requirements... 115 volts AC, 60 cycles, 150 watts. Cabinet Size... 13" wide x 8½" high x 7" deep. Net Weight... 16 lbs. Shipping Weight... 18 lbs.

Tech Resources | Related Sites | Special Features

Home | History | Hi-Fi & Stereo | Ham Radio | Test Equipment | Computers | Other