[Elecraft] K2 SSB Alignment

[Don Wilhelm]

DW,

When adjusting the carrier balance, you are adjusting for minimum 
transmitted carrier - you want that to be at the lowest level possible.

Yes, if you have something sensitive enough to measure a low RF output 
level - then run the K2 into a dummy load and connect the sensitive RF 
meter across the dummy load - I use an oscilloscope set to the highest 
input sensitivity, the RF voltage level at the correct adjustment point 
may be somewhere between 50 and 100 millivolts so your 'meter' must be 
able to respond to a signal that low (an RF Probe is not likely to be 
sensitive enough on the low end of the scale).  An external receiver 
(set for SSB or CW) can be used to detect the residual carrier signal - 
you ae using it as a 'meter' to tell when the K2 output level is at its 
lowest.

You want to transmit only the SSB carrier and not any sidebands.  Yes, 
you can do as the manual indicates and simply push the PTT button, but 
do not speak into the mic (yes, try to keep it from picking up noise 
too) - any audio into the mic will be converted to RF too and confuse 
your measurement.  You can do it even easier if you remember that the CW 
DOT paddle line and the K2 PTT are one and the same signal - just plug 
your paddles into the K2 and close the DOT paddle (you do not have to 
connect a microphone).

You may have to compromise a small amount between USB and LSB - adjust 
for the smallest residual carrier first in LSB, then switch to USB and 
see if you can make a small adjustment to improve it - re-check LSB and 
bounce back and forth between LSB and USB several times (press the REV 
button to switch sidebands, it is easier than using the MODE button)

I would try it with the stock adjustment trimmer - I do not have any 
trouble adjusting with it and I think a multiturn pot would be overkill 
in this application.

73,
Don W3FPR

DW Holtman wrote:
> Hello,
> 
> I'm trying to align the SSB board on a K2. The manual on page 19 says to do the fine carrier balance adjustment using an external receiver. 
> 
> It says "If you're tuned to a setting that allows you to hear the voice signal, you'll be at the zero-beat frequency of the carrier and will not be able to her a tone."
> 
> What exactly does this mean? Is the receiver tuned to the opposite sideband? Does it matter what sideband the external receiver is on? What is being adjusted? The level of rejection for the opposite sideband? It wants a balance between USB and LSB with as low a signal as possible. Will ambient noise in the room (window air conditioner) be picked up by the mic and affect the readings? Should this be done with the mic disconnected and a jumper to short the PTT pin to ground?
> 
> I ordered a trimmer from Digi Key that will fit in the space of R1, it will have 5 turns to increase the resolution.
> 
> Is there somewhere I can put a high impedance RF Voltmeter and adjust R1 without having to use an external receiver? How would this be done?
> 
> Thanks in advance for any help. I'm a little confused. I know this is a lot of questions, hopefully someone will have some of the answers. The reason I started the alignment is with the 100 watt RF Module installed, when I transmit in LSB, there is power out without talking into the mic?
> 
> Thank you,
> DW Holtman
> WB7SSN
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