[ARC5] CW/MCW

[Kenneth G. Gordon]

On 11 Nov 2013 at 20:07, Fuqua, Bill L wrote:

>   I recall now, instead of "Distance" the term was "Range" on the
>   switch.

Yes. "Range" "Phone" and "Both". The word "Range" stood for the so-called 
airways ranges which were specifically designated frequencies and 
transmitters used to delineate the airways paths. Those "range" transmitters 
are now called NDBs. These sounded the (MCW) letter "A" on one side of 
the beam, a letter "N" on the other side of the beam, and a steady 1020Hz 
tone if the pilot was "riding" the beam correctly. The Morse letters A and N 
exactly "filling" one another in so that a steady tone resulted.

The entire system was, to my mind, ingenious, and required no great 
technical knowledge by the pilot: all he had to do was move his plane to one 
side or the other (once he found the correct beam) until he got a steady tone, 
then follow it.

This is why they were called "Range Filters". In one position of the switch 
(Range) they cut out all the audio EXCEPT the enhanced 1020 Hz "Range" 
tone so one could DF or follow the beam easier. In another position, they 
CUT OUT the 1020 Hz "Range" tone so the pilot could more easily copy any 
audio on the signal. And in the last, "Both", the filter was essentially cut out 
of the circuit.

> I need to find one and double check.

Not necessary. You are correct.

> They are very sharp audio
> filters. Don't know what was inside, my filter was potted. But I do
> know it was a passive LC ckt.

Yes. Exactly. I have at least two different types of those. One like yours and 
a smaller squarish green one used by the Air Force.

They work extremely well. I use the black one which has the sloping front 
and the two phone plugs with my AN/GRC-109. It really helps with a receiver 
that is broad.

Ken W7EKB