[Elecraft] K2: Various Receive Problems

[David Woolley (E.L)]

Jon Perelstein wrote:
> 

> 1.  Receive sensitivity is not good.  Using the same antenna, and with 
> AGC on: 

The K2 is somewhat short on overall gain.  However that is not the same 
as receiver sensitivity, which is related to noise, rather than gain. 
Sensitivity is the minimum signal that will exceed the internally 
generated noise.

>  
> It seems as if the AGC is having too much impact since I have to crank 
> the AF Gain almost all the way clockwise to get decent audio volume with 
> the AGC on (both headphones and speaker)?

R1 adjusts the AGC threshold.
>  
>  
> 2. On receive, stations are either there or not there.
>  
See below.

> Along with this, there is no interference from adjacent signals.  I'm 
> always hearing the strongest station and only the strongest station at 

That's good. If there were a way of achieving that which wasn't being 
used, it would be considered a fault.  There is no capture effect with 
SSB, so the only way of achieving this is good selectivity and good IMD 
performance.

> smaller (to be expected with a tighter filter).  At FIL3 I can hear 
> only the strongest of stations, and then across an extremely narrow
 > signal bandwidth. Finally, at FIL4 I cannot pick up even the strongest
 > signals.

Note that FL1,2,3,4 are selections from a memory.  You need to set 
sensible filter parameters for each of these.

> 3.  As I tune across a CW station's signal, there is no change in audio 
> frequency.

Combined with (1), this indicates that the reference oscillator 
frequency isn't being modified.  You should be able to confirm this by 
using the frequency counter on it.

However, there is an explicit check for this during the assembly process 
and the VFO calibration would fail if it wasn't working.  I don't know 
what happens if you never run the calibration.

>  
> Note that I do not have the SSB module installed, and I'm not sure if 
> I'm supposed to be able to hear SSB in a bare-bones K-2 without the SSB 
> module installed (although it is my understanding that I should be 
> copy SSB).

You do not need the SSB module to receive SSB, and, in fact, if you use 
the standard SSB setup, FL3 and FL4 settings on SSB do not use the SSB 
module for receive.


-- 
David Woolley
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