DX-100B Neutralizing


Neutralizing the DX-100 - Following an October 1956 CQ magazine article as described on a web posting.
Original CQ article by Lloyd Jones W6DOB.

Click link for text of Web Posting:     DX-100 text

Heathkit DX-100B transmitter

DX-100 B PA prior to Neutralizing.

On this particular transmitter, on all bands 40 meters and above,
tuning the PA out of resonance would cause
the PA grid current to change toward either a low value
approaching 1 ma or to a high value approaching 8 ma or more.

Schematic indicating the addition of the
Neutralizing capacitor wire.

Neutralizing wire installed. A 1/4 inch hole was drilled
through the RF shield in line with the unused left hand
lug of the 5763 driver plate tuning capacitor stator.
A four inch piece of #12 TW insulated wire
is soldered to the left hand lug
and oriented thru the hole and toward the plate RFC.

Final positioning of Neut wire.

Final adjustment of the wire is accomplished by bending the wire toward or away from the RFC. Following adjustment of the wire, with grid current set at 4ma, and transmitter loaded to 200 ma plate current at resonance, tuning the PA Amplifier tuning out of resonance by 100 ma CW or CCW, the grid current varies less than 1 ma on all bands.