For those list members who read Bob Gunderson's Braille Technical 
Press, do you remember the advertisement for Grand Central Industries?

One of the items this company sold was a brand of solid state gadgets 
such as very low power audio amplifiers, AM broadcast band part 15 
transmitters, etc. The manufacturer was Round Hill Industries.

This was long before single chip circuits. These devices were 
assembled from individual components, and then fully sealed in epoxy, 
with bare wires protruding from the edges for connection to the power 
sourse, speakers, etc.

They were literally the size of an ice cube, which for the late 
1960's, was indeed minuscule. While I never confirmed it other than by 
hearsay, someone told me that the company did in fact use ice trays as 
the mold for the sealed units.

One of the gadgets this company made was a "CW Monitor." The purpose 
of this monitor was to provide the side tone which we now take for 
granted, but which did not come with most rigs of the day, and was an 
add on option for only a few transceivers.
You connected two wires to a small speaker, two others to a single D 
cell, and another to a few feet of hook up wire, which served as the 
antenna.

Then, when you transmitted CW, the thing would squawk, thus giving you 
a means of monitoring what you were sending.

Yesterday, I discovered a box of odds and ends left from the equipment 
of my late friend, K5ZFM.

In the bottom of that box was one of the Round Hill CW Monitor 
modules, still attached to an old portable radio speaker and battery 
holder. I will clean it up and try it out later this week.

The one that I bought on his advice as a Novice in 1969 gave up the 
ghost many years ago.








Mike Duke, K5XU
American Council of Blind Radio Amateurs