Topband: 160m Noise Level

[Jim Brown]

On 11/27/2024 1:44 PM, Roger Kennedy wrote:
> Anyone who says they have a lower noise level these days probably has an
> inaccurate S Meter,

An S-meter measures only the electrical voltage at the antenna terminal, 
and it's only accurate if the electronics driving the meter is both 
properly calibrated and has a linear response over the required range. 
How much voltage is on that antenna terminal quite dependent on the 
antenna that's connected.

In other words, S-meter readings do NOT give any accurate reading of the 
field strength of any signal or noise. Instruments to do that are called 
"field strength meters," use antennas that are designed for that 
purpose, and the two must be calibrated to each other. They are 
expensive. :)

The S-meters in Elecraft rigs beginning with the K3 ARE properly 
calibrated at the factory to the terminal voltage at the antenna input, 
but they know nothing about the antenna. They can also be re-calibrated 
by the user with an accurate signal generator, and Elecraft has sold an 
inexpensive one designed for this calibration.

73, Jim K9YC