RX Noise with no antenna connected

[Bob Harvey - K2PI]

Hi:  I've been noticing s2-s3 receiver noise on my K3 (SN:2195) with the antenna's disconnected.  I have read the posts about the very sensitive receiver and properly calibrated S-meter, but this noise remains at the same level even with the attenuator engaged.  I have tightened all screws, checked other possible noise sources (I have the rig plugged into a non-switching supply that is itself plugged into an ICE line filter) and still no reduction in noise.  I thought at first this might be an S-Meter calibration issue, but not responding to attenuation strikes me as counter to that.  I don't have access to a signal generator, so cannot do much further right now.  Does anyone have any ideas what this could be?  The rig is working very well otherwise.

73,

Bob Harvey
K2PI

[wayne burdick]

Hi Bob,

I have a spare XG1 I can send you if you want to do gain calibration,  
but don't have any other means of getting an S9 and S1 signal source.

This is almost certainly a simple calibration issue. You should start  
by running K3 Utility's "RF GAIN Cal" routine, selecting factory  
defaults, which doesn't require a signal generator. You can follow  
this with tweaking of CONFIG:SMTR OF and SMTR SC until a no-signal  
condition gives you no bars.

73,
Wayne
N6KR

On Oct 13, 2009, at 10:11 AM, Bob Harvey - K2PI wrote:

>
> Hi:  I've been noticing s2-s3 receiver noise on my K3 (SN:2195) with  
> the
> antenna's disconnected.  I have read the posts about the very  
> sensitive
> receiver and properly calibrated S-meter, but this noise remains at  
> the same
> level even with the attenuator engaged.  I have tightened all screws,
> checked other possible noise sources (I have the rig plugged into a
> non-switching supply that is itself plugged into an ICE line filter)  
> and
> still no reduction in noise.  I thought at first this might be an S-
> Meter
> calibration issue, but not responding to attenuation strikes me as  
> counter
> to that.  I don't have access to a signal generator, so cannot do much
> further right now.  Does anyone have any ideas what this could be?  
> The rig
> is working very well otherwise.
>
> 73,
>
> Bob Harvey
> K2PI

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