Most radio receivers made in the 1920's controlled the volume by attenuating the signal to the grid of the first RF amplifier by means of a variable resistor in the antenna input. This resistor (usually 2 - 3K) was a heavy duty wire-wound rheostat!

I'm sure some of you may wonder why a 4 watt wire wound pot is needed for a volume control. If any of you have attempted to replace this control with a conventional pot of the same value, then you know a typical carbon pot works poorly. Why is that? Well here are my thoughts on this issue:

• Carbon pots were not common in the early days and those that were available did go low enough in resistance to attenuate the signal adequately when dealing with a strong signal.

• The wire-wound pot with it's loop arrangement served also as a variable inductor that was more efficient at attenuating the signals as it tracked well at the low resistances needed on a strong signal.

• Considering that lightening was always an issue when the typical antenna of the day was high in the air and about 100' long. So even a mild static discharge into the antenna would destroy a low power, carbon rheostat.

I've not read anything about this issue, these are my thoughts and I stand to be corrected. If any of you have something to add or wish to disagree, please do so, I will appreciate any input.