[Elecraft] K2 receiver sensitivity on 12 and 10 Meters

[Hans J Rasmusen OZ7BQ]

Dear Don and Matt,Thank you for your comments. I know that being able to hear the antenna noise, should indicate that the sensitivity is OK.Measuring the noise level on the K2 speaker output indicate that the noise level incease 4 to 6 dB on 10 Meters, but barely on 12 M when the antenna is connected. The difference is just audible, and the general RX signal level is lower than on other bands.Peaking the filter does not improve the RX. TX produce full output on both bands.
73 OZ7BQ  Hans Jørgen
 

     Den 0:44 torsdag den 6. november 2014 skrev Don Wilhelm <w3fpr at embarqmail.com>:
   

 Hans,

I would suggest you try re-peaking the K2 bandpass filters using 
Transmit.  Set the power to 2 watts and adjust the 10 meter inductors 
for maximum output (L12 and L13) using TUNE, then switch to 12 meters 
and adjust C44 and C46 for maximum output.  That should produce the best 
setting for both transmit and receive.

If connecting the antenna when tuned to those bands results in an 
increase in noise in the receiver, you have all the sensitivity you can 
use.  You should be using real signals (but weak ones) to compare 
receiver sensitivity - if you are comparing on the basis of the 
'loudness' of the noise heard, that can create a false impression.  What 
is important is the signal that stands above the atmospheric noise.

73,
Don W3FPR

On 11/5/2014 4:41 PM, Hans J Rasmusen OZ7BQ wrote:
> My K2 (ser 04069) appears to lack a bit of receiver sensitivity on 12 and 10 Meters. I can hear stations and the static noise when the antenna is connected, only weaker than on other bands.
> I have full TX power output on both bands, so the filters appears to be tuned correctly.I only noticed the apparent lower sensitivity on 12 and 10 Meters after adding a KX3 to the station.My plan is to rig the K2 up as second receiver for split operation on a special RX antenna using the K2 Rcvr Antenna module.
> If the apparent lower sensitivity on 12 and 10 Meters is normal, so be it. However, I wonder if any one has made the same observations and found a solution.
>
>