[Elecraft] Gain calibration

[George, W5YR]

I built two 45 dB pi-network resistive attenuators in a small project box
with double-sided PCB stock for shielding between sections.

Actual attenuation checks out at 91 dB at 20 KHz.

This device is placed on the output of the Icom 756 PRO set for minimum
output of about 1.55 watts. At that level, the signal delivered through the
attnuator to the K2 is S5 on the meter. 

Using that as a "standard input signal" I can compare the output audio
level before and after the crystal changes.

I also have a noise generator I use for alignment and spectral plotting
that will make a good standard input signal for comparison. In fact, I used
it to plot all the spectra for all modes and filters prior to the crystal
installations, and will do so again after the mods are complete.

Now if I can just make enough time to do this and 20 other things!   <:{

I think that we need to keep in mind that all of our K2's differ to varying
degrees in several respects. So, I am not terribly confident that my
measurements would indicate a great deal numerically for another K2. So,
the outcome is likely to be largely subjective.

73/72, George    
Amateur Radio W5YR -  the Yellow Rose of Texas
In the 57th year and it just keeps getting better!
Fairview, TX 30 mi NE of Dallas in Collin county EM13qe
K2 #489      Icom IC-765 #2349     Icom IC-756 PRO  #2121

Don Brown wrote:
> 
> Hi
> 
> DeMaw has a circuit in Solid State Design of a low level signal generator. It uses double sided circuit board to form a shielded box with separate compartments for the oscillator and each section of the attenuator. It uses feed through capacitors for the power and uses a battery to keep the RF from feeding up through a power supply. It has an output of around -100 dbm and he goes into some detail about the shielding requirements to do this without leakage.
> 
> He suggests calibrating it against a commercial generator using a receiver with the AGC off as an indicator. Again not something a lot of people will have access to.
> 
> As I said it can be done but I don't think I would want to try to kit something like this.
> 
> Don Brown
> KD5NDB