[Towertalk] 1.7 db gain

[Tom Rauch]

> The argument is that 1.7 db is just noticeable to most human ears,
> however Force12 literature suggests that even that small a difference
> may cause the AGC in the received signal to favor the louder station. 
> Is the effect then greater than just the difference that a 1.7db would
> appear to be?

The mechanisim they describe is not true, but the effect is. 

One dB can mean a large increase in readability when a signal is 
in the presence of QRM or noise, but it has noting to do with AGC. 
It works the same with the AGC off, as long as the receiver is not 
overloading.
 
> >From experience, I know that 1.7 db doesn't amount to much with clear
> channel, S5 or greater signals but how effective is it for weak
> signals?

It is a signal ratio problem, which is entirely different than absolute 
level changes on a clear channel when the signal is far above noise 
level.

it does not matter if the signal is S5 or 20-over-nine, or if you are 
using AGC or manual gain. If you have a signal that is in noise or 
QRM, and increase it one dB, the difference in readability can be 
quite profound. If you have an S-5 signal on a clear frequency 
without any noise, and increase it one dB, you probably won't be 
able to tell anything happened.
73, Tom W8JI
W8JI@contesting.com