Who remembers Johnson Messenger "Black Tube"

[NightOwl3261]

Curious if anyone remembers from the 1970's the "BLACK TUBE" that was available to supposedy increase radio output?

I never really knew what this replacement tube did or what increase in Watts out it was capable of, but I remember licensed CB operators sneaking the black tube into their beloved Johnson Messengers. I had seen it in ads / catalogs back then along with such things such as Sonar amplifiers all with disclaimers at the time as "for amateur radio use only".

 

[OldTech03]

It was simply a bridge rectifier inside a black shell it increased the plate voltages which increased power.

 

[unit_399]

It was a solid state full wave rectifier that replaced the 6BW4 or 12BW4 rectifier tube. This raised the plate voltage slightly. More importantly, it eliminated the heat generated by the tube and also eliminated the current draw of the tube filament. Another common mod was to bridge a wire across the 3900 ohm resistor in the B+ line to the final tube. the result of these two mods raised the transmitter output to about 8-10 watts. This was commonly referred to as the "STRAP AND DIODE" mod.

- 399

 

[Recon]

Curious if anyone remembers from the 1970's the "BLACK TUBE" that was available to supposedy increase radio output?

I never really knew what this replacement tube did or what increase in Watts out it was capable of, but I remember licensed CB operators sneaking the black tube into their beloved Johnson Messengers. I had seen it in ads / catalogs back then along with such things such as Sonar amplifiers all with disclaimers at the time as "for amateur radio use only".

I don't know about the "black tube" but I had a Johnson mobile CB radio (1971-1973?) which resembles a telephone. It was sort of a beige color but I cannot remember the model name.