[Elecraft] K3_P3_160_CW

[Alan Bloom]

The P3 keeps track of the preamp/attenuator status reported by the K3 so
that the dBm or S-unit display reads accurately.  That can lead to some
non-intuitive behavior.  For example, turning on the K3 preamp typically
makes the noise level on the P3 go down rather than up.  The reason is
that the P3 is turning down its gain to compensate for the increased
gain in the K3.

However this doesn't always work correctly when switching the RX antenna
on the K3.  Currently the K3 does not send an update to the P3 if
switching antennas causes the preamp or attenuator status to change.
This is on Wayne's bug list.

Alan N1AL


On Sun, 2011-04-17 at 12:21 -0700, Ken Roberson wrote:
> Wayne,
> 
> While working 160M DX last winter I noticed that when I
> Switch from RX antenna (Beverage) and back to TX antenna
> That the base line (Noise floor) on the P3 was about 2 S unites
> Less than when I changes to the RX antenna.
> 
> With the default antenna ( TX antenna ) PreAmp = off and ATT = ON
> Switch to RX antenna (with the preamp off) turn the preamp on and switch back to normal antenna.
> Now if you switch the preamp on and off, the base line will return to normal.
> Hard for me to explain.
> 
> Thanks Ken K5DNL
> 
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