Posted by
Don Wilhelm-4 on
Jan 17, 2011; 2:07am
URL: http://elecraft.85.s1.nabble.com/NG0R-KSB2-low-audio-level-tp5930478p5930545.html
John,
To answer your question, I suggest getting the transverters out of the
equation - there are too many variables right now. Let's try to take it
one step at a time.
Do you have an oscilloscope? If so, try 40 meters into a dummy load -
note the amplitude of a CW signal on the 'scope. Then switch to SSB and
speak into the mic - are the SSB peaks as great as the CW amplitude?
They should be. If they are, then the K2 is delivering the full PEP
requested by the power control and you need to look for problems other
than the K2, and your wattmeters may be indicating something other than
the peak power.
If you do not have an oscilloscope, do you have a peak reading
wattmeter? What does that meter say about the SSB peak power?
What I am trying to discover is whether the problem is related to the
base K2 or some problem with the transverters. Taking the transverters
out of the picture and getting a reading on the behavior of the K2 on 40
meters will be revealing.
Please include the vintage (or serial number) of the K2 and when was the
KSB2 option purchased?
73,
Don W3FPR
On 1/16/2011 8:10 PM, John Hoaglun wrote:
> I need some help troubleshooting an issue.
>
> K2+KSB2+K160RX+KIO2+KAT2+K60XV+XV144+XV222+XV432+IMA rework module
>
> I have not spent much time using this rig on SSB but I plan to use it to
> drive the transverters. So as part of the setup& checkout of the system
> I am noticing that my SSB power level seems pretty low compared to my CW
> power level. Specifically when I test my transverters I am getting my
> expected power on all of them with CW. (The transverter power level on
> each unit is setup for driving the input power level for the brick for
> that band.)
>
> 144: 25w CW --expected
> 222: 10w CW --expected
> 432: 10w CW --expected
>
> When I change over to SSB the power level is almost nothing
> 144: 1-2w SSB
> 222: less than 1w SSB
> 432: less than 1w SSB
>
> I am using an Icom HM-36 mic (and have tested with two Heil headsets
> with similar results). SSBA=3 and SSBC=4-1
>
> Initially I was thinking that I had an issue with Mic bias but I am not
> so sure now. I configure my computer to send modulated CW over SSB to
> compare the output level against a native CW signal. The spread matches
> the info above.
>
> It appears that my SSB audio level is attenuated for some reason. (The
> audio reports are good with no distortion.)
>
> Any suggestions for where to look on the KSB2 or an adjustment that I
> might have missed?
>
> 73 de NG0R
>
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