[Elecraft] K3 receiver noise questionable test results

[Don Wilhelm]

Mike,

That could easily happen if you have the AGC on.  That would be 
especially true if you have the preamp on when it is not needed and are 
running the RF Gain at its full setting.  With a signal present, the AGC 
is acting to keep the receiver gain low, but when the signal is no 
longer present, the receiver bounces back to full gain.

Try the same test with the AGC off and the preamp off (even with the 
attenuator on) and the RF Gain backed down so the no-signal noise with 
your vertical connected is just perceivable.  Then tune in a signal, 
note its strength and remove the antenna.  The noise level should be 
absent (unless you have the AF Gain set really high).  If you still get 
noise with no antenna, you have a receiver fault that needs attention.

73,
Don W3FPR

K2MK wrote:
> One test that I have performed leaves me scratching my head as to its 
> results. Maybe someone can enlighten me. I tune to a medium strength CW 
> signal and press my ANT button to switch between ANT 1 and ANT 2. I have 
> nothing connected to ANT 2. The signal disappears but the background noise 
> level remains the same.
>
> 73,
> Mike K2MK 
>   
>