[CW] Telegraph Sounder Decoding Practice

[Richard Knoppow]

    A note about sounders: There are basically two kinds, a "main line 
sounder" and a "local sounder", the difference is in the resistance and 
operating voltage/current. The most usual arrangement is to have a relay 
and local sounder. The relay works off of the main line, the line that 
goes from place to place, and will have several volts on it depending on 
the length. Main line sounders have fairly high resistance, anywhere 
from about 40 to 150 ohms, sometimes more for special purpose ones. This 
is similar to the resistance of a main line relay. The idea of the main 
line sounder is to operate without a relay, directly from the telegraph 
line. In some cases a relay combines both purposes with a resonator as 
part of the relay. These are sometimes called "box" relays and are 
intended to work in simple set ups.
     A local sounder generally has a resistance of about four ohms. They 
work from the relay on the main line, with an individual battery, 
usually a single cell with about 1.5V. The idea of a local relay is to 
be independent of the condition or voltage of the main line. A main line 
relay or sounder may need constant attention during bad weather while a 
local relay is always just the same. The usual arrangement in all but 
the smallest telegraph offices is for the relay and key to be in line 
with the telegraph line and its batteries, and the local sounder to work 
from a contact on the main line relay. The sounder has no direct 
connection with the telegraph line or key.
     This is all explained in old books on the telegraph but can be 
confusing.
     I don't have any hints about learning to read from a sounder. I 
began learning many years ago but was interrupted and have always had 
difficulty in getting back. Its not the same as tone even if you are 
learning the same code on both. Takes lots of practice.

On 3/26/2025 9:30 PM, D.J.J. Ring, Jr. wrote:
> Re: Telegraph Sounder Decoding Practice???
> 


-- 
Richard Knoppow
Los Angeles
WB6KBL
SKCC 19998