[Elecraft] Elecraft : K2 SSB audio quality

[Don Wilhelm]

Martin,

You may be driving the internal ALC too hard.  With the MH2 mike, it is 
rare to have to use SSBA higher than 1.  Try bumping up the compression 
to 3, I think you will like it better. 

A HiCur message only relates to the base K2, not the KPA100, and means 
the current set in CAL CUR is being exceeded.  Make certain CAL CUR is 
set to 3.50 and if the HiCur messages persist, check the windings of T4 
and the LPF in the base K2 for any problems.
Of course, the LPF of the KPA100 is also in-line, so there could be a 
possibility of a problem in that LPF too.
If it is a LPF problem, the HiCur problem will only occur on one or two 
bands.  If it is on all bands, look to the power supply and the cable(s) 
and connectors.  Everything should be tight.  On SSB, the instantaneous 
current change can be higher than with CW and if there is too much 
resistance in the power supply system, the voltage could drop for an 
instant and create a HiCur situation.

If you are setting the power control to "full right" instead of 100 
watts, that could also be the cause of the occasional HiCur messages and 
power overshoot.  In the full right position, there is not as much 
control headroom, the K2 is trying to drive "flat out".

73,
Don W3FPR

Martin.Evans at costain.com wrote:
> Hello, I've recently started to use my K2/KPA100 on SSB running 100W
> with an MH2 mike mostly on 80m. I use 2:1 compression and mic preamp is
> set to 2. The antenna is an 120ft doublet, 30ft of 300ohm ribbon feeder,
> remote mounted z match tuner right under the centre of the doublet and
> approx 70ft RG58 coax to the rig. I have no RF earth but neither do I
> get much RFI in the house. One end of the antenna is about 10m above the
> operating position and I'm on the ground floor. I've had varying reports
> on the audio quality. Here are a few things I have done/found:
>  
> Every now and then I would get a high current message after which my RF
> peaks (as shown on the K2 bargraph) would drop right down. My remote
> mounted z match tuner uses old broadcast receiver variable caps and I
> think one of them might have been flashing on speech peaks. I have
> backed off the power to 90W and it seems a lot better. The funny thing
> is that when I run at 100W on CW I don't have any probs (ie no high
> current messages). Is there something about the RF peaks on SSB, do they
> overshoot sometimes or is it something to do with rate of rise of the RF
> voltage?
>
>