[TenTec] TenTec] TX EQ = -14 dB for PSK31

[Dr. Gerald N. Johnson]

On Fri, 2006-12-29 at 15:06 -0500, K4IA at aol.com wrote:
> I guess my use of the term "non-linearities" is a misnomer.  What  I meant to 
> describe was something like this:  
> 
> If I am operating SSB and I turn down the mic gain and transmit with the  mic 
> gain too low, the audio doesn't sound "full."  It may be totally linear  but 
> it is hard to understand and weak.

So the signal level is reduced until the receive S/N is poor. It
shouldn't matter whether its that way from low audio gain or a poor
propagation path.

> Isn't that the same thing as  turning down 
> the audio drive on PSK to reduce the final output to the desired 25  watts 
> when the transmitter is set to put out  100w?    Wouldn't it give the same 
> result, a thin  under-driven and hard-to-copy signal?

Only when it makes the receive signal to noise ratio poor which is the
same thing as happens with poor propagation.
>  
> The debate is whether it is better to:
>  
> 1.  Set the transmitter at 100w and only supply enough audio to put  out 25w, 
> or
>  
> 2.  Set the transmitter at 25w and use enough audio to drive it to the  full 
> 25w or slightly under.

These two conditions should produce nearly the same result. Just that
the 25 watt ALC setting will do more compression. Linearity outside of
the compression should be the same.
>  
> The fact the Orion's ALC circuit and software are somewhat of a mystery  sure 
> doesn't help answer the question.  
> 
> k4ia
> 
>